Report number NordFoU EAN number NordTyre Part 3 Noise from Truck Tyres

Transcription

1 Report number NordFoU EAN number NordTyre Part 3 Noise from Truck Tyres

2 Project NordTyre Part 1+2 Report number NordFoU Date December 2017 Project manager Jørgen Kragh, Danish Road Directorate Members of the project group Jørgen Kragh (project leader), Danish Road Directorate Rasmus Holck Stahlfest Skov, Danish Road Directorate Jens Oddershede, Danish Road Directorate Hans Bendtsen, Danish Road Directorate Financial partners Norwegian Public Roads Administration (NPRA) (Vegdirektoratet) Danish Road Directorate (Vejdirektoratet) Swedish Transport Administration (Trafikverket) Project Steering Committee Espen Andersson (Chair) and Jannicke Sjøvold, Norwegian Public Roads Administration Jakob Fryd, Danish Road Directorate (Vejdirektoratet) Martin Hellung-Larsen, Danish Transport Authority until 2016 Peter Smeds, Swedish Transport Administration until 2016 Julia Bermlid, Swedish Transport Administration from 2017 Report title NordTyre Part 3 Noise from Truck Tyres Abstract The main objectives of the project were to: Clarify the real influence of the new tyre noise labelling of C3 truck tyres Establish scientific evidence on the tyre/road contribution to traffic noise emission from roads in the Nordic countries Generate a basis for qualified decision making concerning actions to mitigate traffic noise in the Nordic countries To define realistic new tyre noise limits for use in a future revision of the EU tyre labelling and the tyre noise limits, including rolling resistance and supplementing the labelling of wet grip with labels of snow grip and ice grip Demonstrate the usefulness or necessity of a second roughly textured ISO reference test track for tyre noise testing and labelling, hence creating scientific arguments for a short term revision of EU tyre noise regulation Measurements of noise from 30 different truck tyre sets have been carried out by M+P at Twente Proving Ground in The Netherlands. The 30 tyres were: 8 steering axle, 12 drive axle (9 original, 3 retreated) and 10 Trailer axle tyres (6 original, 4 retreated). Measurements were performed at four different surfaces: ISO surface, Stone Mastic Asphalt (SMA 11), Thin Surface Layer (TSL 8) and Dense Asphalt Concrete (DAC 16). The analysis of the noise levels from the tyres illustrates big differences between labelled noise levels, and measured noise levels in this project. Dependent of the tyre type the measured noise levels on an average were 2.3 to 3.1 db higher than the labelled levels. However, when using the method described in UNECE R117 with up to 0.9 db truncation and 1 db deduction from the measurement results, the measured levels on an average were 0.8 to 1.5 db higher than the labelled levels. 9 out of 17 tyres after truncation and deduction of 1 db had measured levels over the labelled levels. It can be concluded that the measured noise levels were higher than the labelled noise levels for half of the tested tyres. The range of the noise levels measured on the ISO surface is 6 db for Drive and Steer tyres and just 1 db for the Trailer tyres whereas for the SMA surface the range is only 1 to 2 db for all three tyre types. This shows that the smooth ISO surface is more sensitive to different tyre lines than the rougher SMA surface. The measurements performed at the retreaded tyres show that the retreaded tyres are noisier than the original tyres. If the retreaded tyres were subject to regulation as the new tyres are, the potential for noise reduction would be bigger. The measurements show that there are big differences in the potential noise reductions at the four surfaces. The noise levels at the SMA surfaces were higher than at the other surfaces. Since the Nordic countries are mainly using SMA surfaces, the potential tyre/road noise reductions from using SMA 8 pavements rather than SMA 11 or SMA 16 are bigger than from regulating the use of truck tyres. The potential when changing from SMA 16 to SMA 11 is 1.3 db and from SMA 11 to SMA 8 is 0.7 db.

3 Analysis of the potential noise reduction obtained if regulating the use of the different tyre types on different pavement types were carried out. To describe the influence of regulating the tyres the background was a typical truck configured with different types of tyres. The truck was configured by the following axles and tyres: 1 steer axle, 1 drive axle (50 % retreaded tyres), and 4 trailer axles (50 % retreaded tyres). The potential from regulating the new tyres to only using the % least noisy (measured on the ISO surface), and configuring the truck as described above, is a 0.8 db reduction of the tyre/road noise at the ISO surface (used for labelling) but just 0.2 db for the SMA surface type used in the Nordic countries. If the surfaces were changed together with regulating the tyre use, a potential reduction of tyre/road noise in Norway would be 2 db by using SMA 8 instead of SMA 16, and in Denmark 0.7 db by using SMA 8 instead of SMA 11. As the trucks are not responsible for all of the traffic noise, the potentials of the reducing the noise from the trucks have been weighted with the share of the noise which they are responsible for. Scenarios of the impact on noise annoyance experienced by the populations in Norway and Denmark have been developed on the background of national noise mapping. For the Norwegian case the Noise Annoyance Index (Støyplageindeks - SPI) is reduced by 1 % by reducing the new tyres to the 25-33% least noisy tyres and lowering the noise by means of the surface. For the Danish case the Noise Annoyance Number (Støjbelastningstal SBT) is reduced by 2 %. Overall the investigations show that the potential reduction of the noise from truck tyres is much smaller at the Nordic surface types SMA than on the ISO test surface used in the tyre noise labelling system. The reduction potential is especially affected by the fact that retreaded tyres are not a part of the labelling system. Keywords Truck tyres, noise measurements, noise labelling, Nordic road surfaces, scenarios for noise annoyance Language English Number of pages 78

4 NordTyre Part 3 Noise from Truck Tyres Date 1 January 2018 Contact Hans Bendtsen Mail hbe@vd.dk Phone Document 15/ Page 1/78

5 1 Preface This report documents the results of an investigation into noise from new truck tyres based on a large series of measurements. One of the purposes of the report is to analyse the potential effect of the latest EU noise limits and noise labels for type approval of truck tyres. The target group for the results of the NordTyre project is road administrators. The present report should be considered a background report documenting technical aspects concerning truck noise in a way similar to the way noise from cars was dealt with in the final report on Part 2 of NordTyre [Kragh, 2015]. The present report is the main deliverable from Part 3 of the NordTyre project initiated by NordFoU, which is a research and development framework for the Nordic state road administrations (see: www/nordfou.org/). This truck tyre project is a follow up on a similar NordFoU project on passenger car tyres [Berge, 2012; Kragh, 2015]. The NordTyre project was funded by NordFoU with contributions from: Danish Road Directorate, (DRD) (Vejdirektoratet) Norwegian Public Roads Administration (NPRA) (Statens Vegvesen, Vegdirektoratet) Swedish Transport Administration (Trafikverket) In a companion report, a summary will be given focussed on regulatory aspects of tyre/road noise. Steering group members were: Espen Andersson (Chair) and Jannicke Sjøvold, Norwegian Public Roads Administration (Statens Vegvesen, Vegdirektoratet) Nina E. Landvik, Climate and Environmental Directorate, Norway (Klima- og forurensningsdirektoratet), (observer) until 2016 Jakob Fryd, Danish Road Directorate (Vejdirektoratet) Martin Hellung-Larsen, Danish Transport Authority (Trafikstyrelsen) until 2016 Peter Smeds, Swedish Transport Administration (Trafikverket) until 2016 Julia Bermlid, Swedish Transport Administration (Trafikverket) from 2017 Advisory group members were: Luc Goubert, Belgian Road Research Centre, BRRC Ulf Sandberg, Swedish National Road and Transport Research Institute, VTI Ingunn Milford, Multiconsult, Norway Roger Williams, independent tyre expert, United Kingdom until 2015 Jan Boe Kielland, independent noise expert, Norway Project group members were: Jørgen Kragh, Danish Road Directorate until May 2016 when he retired Rasmus Stahlfest Holck Skov, Danish Road Directorate until fall 2017 and then DELTA/FORCE Technology Jens Oddershede, Danish Road Directorate until October 2017 and then DELTA/FORCE Technology Hans Bendtsen, Danish Road Directorate The main authors of the report are Jørgen Kragh and Rasmus Stahlfest Holck Skov with contributions from other members of the project group. The report has been finally edited by Hans Bendtsen and Rasmus Stahlfest Holck Skov. Measurements performed in NordTyre part 3 were carried out by M+P Consulting Engineers, The Netherlands and by SINTEF, Norway. Side 2 af 78

6 2 Forord I denne rapport dokumenteres en undersøgelse af støj fra nye dæk til lastbiler. Undersøgelsen er baseret på en stor serie målinger. Et af formålene var at analysere potentielle effekter af EU s støjgrænser og mærkning samt typegodkendelse af nye dæk til lastbiler. Målgruppen for resultaterne af dette NordTyreprojekt er vejadministrationer. Denne rapport skal ses som en baggrundsrapport, der dokumenterer de tekniske aspekter vedrørende støj fra lastbiler herunder lastbildæk, på samme måde som støj fra personbiler og dæk blev behandlet i den afsluttende rapport fra del 2 af NordTyre-projektet [Berge, 2012; Kragh, 2015]. Herværende rapport er hovedleverancen fra del 3 af NordTyre-projektet, som er startet af NordFoU, der er en ramme for forsknings og udviklings samarbejde for de statslige nordiske vejadministrationer (se: www/nordfou.org/). Der vil blive udarbejdet en rapport, som sammenfatter resultaterne fra undersøgelserne af dæk til henholdsvis lastbiler og personbiler. Dette NordTyre-projekt blev finansieret af NordFoU med tilskud fra: Vejdirektoratet i Danmark Statens Vegvesen i Norge Trafikverket i Sverige Projektets styregruppe havde følgende medlemmer: Espen Andersson (formand) og Jannicke Sjøvold, Statens Vegvesen i Norge Nina E. Landvik, Klima- og forurensningsdirektoratet i Norge, (observatør) indtil 2016 Jakob Fryd, Vejdirektoratet i Danmark Martin Hellung-Larsen, Trafikstyrelsen i Danmark (indtil 2016) Peter Smeds, Trafikverket i Sverige (indtil 2016) Julia Bermlid, Trafikverket i Sverige fra 2017 Projektets rådgivende ekspertgruppe bestod af: Luc Goubert, det belgiske vejforsknings center, BRRC Jan Bo Kielland, selvstændig støjekspert, Norge Ingunn Milford, Forsvarsbygg future i Norge Panu Sainio, Aalto Universitet, Finland Ulf Sandberg, Det nationale svenske väg- och transportforskningsinstitut, VTI Roger Williams, selvstændig dækekspert, England (indtil 2015) Projektgruppen havde følgende medlemmer: Jørgen Kragh, Vejdirektoratet i Danmark, projektleder (indtil maj 2016 hvor han gik på pension) Rasmus Stahlfest Holck Skov, Vejdirektoratet i Danmark indtil efteråret 2017 og efterfølgende DEL- TA/FORCE Technology Jens Oddershede, Vejdirektoratet i Danmark indtil oktober 2017 og efterfølgende DELTA/FORCE Technology Hans Bendtsen, Vejdirektoratet i Danmark Side 3 af 78

7 Rapportens hovedforfattere er Jørgen Kragh og Rasmus Stahlfest Holck Skov med bidrag fra de andre medlemmer af projektgruppen. Den endelige redigering af rapporten er foretaget af Hans Bendtsen og Rasmus Stahlfest Holck Skov. Målingerne i NordTyre del 3-projektet blev udført af M+P Consulting Engineers i Holland samt af SINTEF i Norge. Side 4 af 78

8 3 Summary The main objectives of the project were to: Clarify the real influence of the new tyre noise labelling of C3 truck tyres Establish scientific evidence on the tyre/road contribution to traffic noise emission from roads in the Nordic countries Generate a basis for qualified decision making concerning actions to mitigate traffic noise in the Nordic countries To define realistic new tyre noise limits for use in a future revision of the EU tyre labelling and the tyre noise limits, including rolling resistance and supplementing the labelling of wet grip with labels of snow grip and ice grip Demonstrate the usefulness or necessity of a second roughly textured ISO reference test track for tyre noise testing and labelling, hence creating scientific arguments for a short term revision of EU tyre noise regulation Measurements of noise from 30 different truck tyre sets have been carried out by M+P at Twente Proving Ground in The Netherlands. The 30 tyres were: 8 steering axle, 12 drive axle (9 original, 3 retreated) and 10 Trailer axle tyres (6 original, 4 retreated). Measurements were performed at four different surfaces: ISO surface, Stone Mastic Asphalt (SMA 11), Thin Surface Layer (TSL 8) and Dense Asphalt Concrete (DAC 16). The analysis of the noise levels from the tyres illustrates big differences between labelled noise levels, and measured noise levels in this project. Dependent of the tyre type the measured noise levels on an average were 2.3 to 3.1 db higher than the labelled levels. However, when using the method described in UNECE R117 with up to 0.9 db truncation and 1 db deduction from the measurement results, the measured levels on an average were 0.8 to 1.5 db higher than the labelled levels. 9 out of 17 tyres after truncation and deduction of 1 db had measured levels over the labelled levels. It can be concluded that the measured noise levels were higher than the labelled noise levels for half of the tested tyres. The range of the noise levels measured on the ISO surface is 6 db for Drive and Steer tyres and just 1 db for the Trailer tyres whereas for the SMA surface the range is only 1 to 2 db for all three tyre types. This shows that the smooth ISO surface is more sensitive to different tyre lines than the rougher SMA surface. The measurements performed at the retreaded tyres show that the retreaded tyres are noisier than the original tyres. If the retreaded tyres were subject to regulation as the new tyres are, the potential for noise reduction would be bigger. The measurements show that there are big differences in the potential noise reductions at the four surfaces. The noise levels at the SMA surfaces were higher than at the other surfaces. Since the Nordic countries are mainly using SMA surfaces, the potential tyre/road noise reductions from using SMA 8 pavements rather than SMA 11 or SMA 16 are bigger than from regulating the use of truck tyres. The potential when changing from SMA 16 to SMA 11 is 1.3 db and from SMA 11 to SMA 8 is 0.7 db. Analysis of the potential noise reduction obtained if regulating the use of the different tyre types on different pavement types were carried out. To describe the influence of regulating the tyres the background was a typical truck configured with different types of tyres. The truck was configured by the following axles and tyres: 1 steer axle, 1 drive axle (50 % retreaded tyres), and 4 trailer axles (50 % retreaded tyres). The potential from regulating the new tyres to only using the % least noisy (measured on the ISO Side 5 af 78

9 surface), and configuring the truck as described above, is a 0.8 db reduction of the tyre/road noise at the ISO surface (used for labelling) but just 0.2 db for the SMA surface type used in the Nordic countries. If the surfaces were changed together with regulating the tyre use, a potential reduction of tyre/road noise in Norway would be 2 db by using SMA 8 instead of SMA 16, and in Denmark 0.7 db by using SMA 8 instead of SMA 11. As the trucks are not responsible for all of the traffic noise, the potentials of the reducing the noise from the trucks have been weighted with the share of the noise which they are responsible for. Scenarios of the impact on noise annoyance experienced by the populations in Norway and Denmark have been developed on the background of national noise mapping. For the Norwegian case the Noise Annoyance Index (Støyplageindeks - SPI) is reduced by 1 % by reducing the new tyres to the 25-33% least noisy tyres and lowering the noise by means of the surface. For the Danish case the Noise Annoyance Number (Støjbelastningstal SBT) is reduced by 2 %. Overall the investigations show that the potential reduction of the noise from truck tyres is much smaller at the Nordic surface types SMA than on the ISO test surface used in the tyre noise labelling system. The reduction potential is especially affected by the fact that retreaded tyres are not a part of the labelling system. Side 6 af 78

10 4 Sammenfatning Projektets hovedformål var følgende: At klarlægge den reelle betydning af den nye dækstøj mærkning af C3 lastbil-dæk Foretage en videnskabelig undersøgelse af dæk/vejbanestøjens bidrag til den samlede støjemission fra vejtrafik i de nordiske lande At udvikle en platform for kvalificeret beslutningstagen om tiltag til at mindske trafikstøjen i de nordiske lande At definere realistiske nye støjgrænser for dæk som vil kunne anvendes i en fremtidig revision af EU s dækmærkningssystem og støjgrænser, også inklusiv rullemodstand samt en supplering af mærkningen for vådt vejgreb med en mærkning af sne vejgreb og is vejgreb At demonstrere nytten og behovet for en ekstra ISO-testbelægning med en grov overfladetekstur til brug ved støjtestning og mærkning af dæk for dermed at skabe en videnskabelig argumentation for en revision af EU's dækstøjregulering på kort sigt Målinger af støj fra 30 forskellige sæt dæk til lastbiler er blevet udført af firmaet M+P på "Twente Proving Ground i Holland. De 30 sæt dæk bestod af 8 dæk til styreakslen, 12 dæk til drivakslen (9 originale og 3 regummierede) samt 10 til trailerakslen (6 originale og 4 regummierede). Støjmålingerne blev udført på 4 forskellige vejoverflader: ISO-testbelægning, skærvemastiks (SMA 11), tyndt slidlag samt tæt asfalt beton (AB 16t). Analyserne af støjniveauerne målt på de forskellige dæk viser store forskelle mellem de på mærkningen angivne støjniveauer og de målte niveauer. Afhængigt af dæktype ligger de målte niveauer som gennemsnit 2,3 til 3,1 db over de mærkede niveauer. Men når man bruger den metode, som er beskrevet i UNECE R117 med op til 0,9 db trunkering og fratrækning af 1 db fra måleresultaterne, ligger de målte niveauer som gennemsnit kun 0,8 til 1,5 db over de mærkede niveauer. Det kan samlet set derfor konkluderes, at de målte støjniveauer lå over de mærkede niveauer for halvdelen af de testede dæktyper. Det totale interval for støjen målt på ISO-testbelægningen er 6 db for dæk til driv- og styreaksel samt blot 1 db for dæk til trailerakslen. Målingerne på SMA-belægningen viser derimod, at for dæk til de tre forskellige aksler er det totale interval for støjen blot 1 til 2 db. Dette viser, at den jævne ISO-testbelægning er mere følsom for forskellige dæktyper end SMA-belægningen med en grovere overfladetekstur. Målingerne på de regummierede dæk viser, at disse dæk er mere støjende end de originale dæk. Hvis de regummierede dæk blev reguleret i forhold til støj på samme måde som de originale dæk, ville potentialet for støjreduktion være større. Målingerne viser, at der er en stor forskel I potentialet for støjreduktion på de fire vejoverflader. Støjniveauerne for SMA-belægningen er højere end for de øvrige 3 belægninger. I de nordiske lande anvendes ofte SMA-belægninger. Potentialet for støjreduktion er større ved at anvende en SMA 8-belægning i stedet for SMA 11 eller SMA 16 end ved at regulere brugen af lastbildæk. Potentialet for lastbildæk ved at skifte fra en SMA 16 til en SMA 11 er 1,3 db og fra en SMA 11 til en SMA 8 0,7 db. Der er foretaget analyser af det støjreducerende potentiale ved at anvende de forskellige dæktyper på de 4 forskellige vejbelægninger. For at beskrive betydningen af at regulere dækkene er der defineret en typisk lastbil konfigureret med forskellige dæktyper. Lastbilen var konfigureret med de følgende aksler og dæk: en styreaksel, en trækaksel (med 50 % regummierede dæk) samt fire traileraksler (med 50 % regummierede dæk). Potentialet var en 0,8 db reduktion af dæk/vejbane støjen på ISO-testbelægningen Side 7 af 78

11 som anvendes til støjmærkning ved kun at anvende de % mindst støjende dæk (målt på ISO testbelægningen). For SMA-belægningen, som typisk anvendes i de nordiske lande, er potentialet for reduktion af dæk/vejbane støjen blot 0,2 db. Ved både at udskifte vejbelægningerne samt regulere brugen af dæk, er der et potentiale for reduktion af dæk/vejbane-støjen. I Norge er det beregnet til 2 db ved at anvende SMA 8 i stedet for SMA 16 og i Danmark er det på 0,7 db ved at anvende SMA 8 i stedet for SMA 11. Lastbiler er ikke årsagen til al støj fra vejtrafik, da personbiler ligeledes har betydning. Derfor skal den potentielle støjdæmpning fra lastbiler vægtes med den andel af støjen, som de er ansvarlige for. Der er udviklet nogle scenarier for indvirkningen på støjgenerne oplevet af befolkningen i Danmark og Norge. Disse scenarier er baseret på brug af de nationale støjkortlægninger. I Norge kan Støyplageindekset (SPI) reduceres med 1 % ved at reducere brugen af dæk til lastbiler til de % mindst støjende dæk kombineret med at reducere støjen ved brug af andre belægninger. For Danmark kan Støjbelastningstallet (SBT) reduceres med 2 % Samlet set viser undersøgelserne, at potentialet for reduktion af støjen fra lastbildæk er mindre på nordiske SMA-belægninger end på den ISO-testbelægning, som anvendes i mærkningssystemet for dækstøj. Reduktionspotentialet påvirkes specielt af det faktum, at regummierede dæk ikke er en del af mærkningssystemet. Side 8 af 78

12 Contents 1 Preface Forord Summary Sammenfatning Abbreviations Background and aim Regulation of tyre noise Method applied Limitations Selected tyres Selected pavements Noise measurements Measurement results Data analysis Measured noise levels and noise limits Measured noise levels and tyre labels Noise levels from S, D and T tyres New vs retreaded tyre noise levels Measured noise and labelled fuel efficiency Measured noise and labelled wet grip Relation between L AFmax and L AE Potential noise reduction Principle and Procedure Pavement regulation Tyre regulation Truck configuration Reduction of tyre/road noise from trucks Pavement regulation Tyre regulation Reduction potential for tyre/road noise from a truck Reduction of total noise from trucks Annoyance scenarios Noise annoyance indicators Noise mappings Limitations Definition of scenarios Effect of regulation on annoyance Tonality Discussion and conclusions References Side 9 af 78

13 Appendixes A.1 Tyres, their labels and measured noise levels A.2 Test pavements and their representativity A 2.1 Surface texture A 2.2 CPX noise levels A.3 Truck tyre noise levels on SMA 16, SMA 11, and SMA A 3.1 Noise Levels from SMA 16 vs. SMA 11 pavements A 3.2 Noise levels from SMA 8 vs. SMA 11 pavements A.4 Measured truck tyre noise levels per type of tyre A.5 Tyres sorted according to measurements at TPG ISO surface A 5.1 Distribution of noise level of tyre types A 5.2 Graphical illustration of distribution of noise levels A.6 Noise level potentials for individual tyre types on different pavements A.7 Energy average and reduction potentials for tyre types A.8 Potential from truck based on different tyre sorting A.9 Weighting the share of the total traffic noise A 9.1 Traffic composition A.10 Annoyance scenarios A 10.1 Number of noise exposed dwellings A 10.2 Effects of regulation on the value of overall noise indicators A.11 Effect of regulation on the value of overall noise indicators A.12 Tonality of track tyre noise A.13 Close up photos of the four test surfaces Side 10 af 78

14 5 Abbreviations Abbreviations used in the report A G Classes of fuel efficiency and wet grip for tyres C1 Tyre class for car tyres C2 Tyre class for light truck tyres C3 Tyre class for heavy duty vehicle tyres CB Coast-By Method, UNECE R117 CEDR Conference of European Directors of Roads (see: CPX Close-Proximity method, ISO/DIS DRD Danish Road Directorate (in Danish: Vejdirektoratet) EEC The European Economic Community ERGA Evolution of Regulation Global Approach (EU Commission ad hoc group on a method for measuring tyre/road noise) EU European Union FFT Fast Fourier Transform ISO International Organization for Standardization DTL Dansk Transport og Logistik; Danish association of transport entreprises L AFmax Maximum noise level L AE Sound energy recorded over a time period normalized to a duration of 1 second MPD Mean Profile Depth (see ISO ) M+P M+P consulting engineers in the Netherlands SEL Sound Exposure Level, same as L AE SINTEF Independent Norwegian Research Institute TPG Twente Proving Ground, also denoted Twente Test Track in the Netherlands Side 11 af 78

15 1 Background and aim The steadily increasing traffic noise has caused administrations in Denmark, Norway and Sweden to set national targets for reducing noise annoyance, including working internationally to influence decisionmaking in CEDR/EU/ERGA on noise from vehicles and tyres. An EU Directive has come into force [Regulation (EC) No 1222/2009] and labelling of new vehicle tyres by November 2012 became mandatory in all EU and EEC countries. The tyre label includes classes or values of three parameters: wet grip, rolling resistance and noise. The Directive is used in the type approval process of new tyres for the European marked. Nordic road administrations work on reducing traffic noise exposure by applying noise reducing pavement and by building and maintaining noise barriers which require significant economic resources. There is a need to know how low noise tyres could contribute to traffic noise mitigation and to clarify how this contribution can be optimized. The objectives of the NordTyre project are to: clarify the real influence of the new tyre noise labelling establish scientific evidence on the tyre/road contribution to traffic noise emission from roads in the Nordic countries identify combinations of tyres and pavements which yield the lowest noise emission throughout their lifetime and thereby influencing the environment along roads and highways as little as possible generate a basis for qualified decision making concerning actions to mitigate traffic noise in the Nordic countries to define realistic new tyre noise limits for use in a future revision of the EU tyre labelling and the tyre noise limits, including rolling resistance and supplementing the labelling of wet grip with labels of snow grip and ice grip demonstrate the usefulness or necessity of a second roughly textured ISO reference test track for tyre noise testing and labelling, hence creating scientific arguments for a short term revision of EU tyre noise regulation The NordTyre part 3 is about the impact and possibilities of regulating truck tyres, whereas part 1 and 2 is about the impact and possibilities of regulating passenger car tyres [Berge, 2012; Kragh, 2015]. The focus of this NordTyre part 3 report is on noise related issues. A summary report combining the results from part 1 and 2 as well as part 3 will also be published. The tyre regulation encompasses the tyre classes: passenger car tyres (C1), light commercial vehicle tyres (C2) and heavy commercial vehicle tyres (C3). NordTyre part 3 is therefore only dealing with C3 tyres. A truck is usually equipped with different tyre types, depending on the position at the truck. Figure 1 illustrates different types of tyres at a truck: Steering tyres positioned at the steering axle to optimize handling of the truck; Drive tyres positioned at the drive axles of the truck to give maximum traction of the truck also denoted traction tyres; Trailer tyres positioned at the trailer axles to perform best in free rolling. Steer Drive/Trailer Trailer Figure 1: Illustration of the different tyre types at a truck; Steering (S)-, Drive (D)- and Trailer (T) tyres. Side 12 af 78

16 2 Regulation of tyre noise In 2009, new European tyre noise limits were introduced in the Reg. (EC) No.661/2009. This regulation also includes requirements for wet grip and rolling resistance. The new noise limits entered into force beginning 1-Nov-12. Regulation on labelling tyres with respect to fuel efficiency, wet grip and noise also became effective, beginning 1-Nov-12 [Reg (EC) No.1222/2009], amended 30-Nov-11 [Reg (EU) No. 1235/2011]. Fuel efficiency and wet grip are classified into categories A - G, where category A has the lowest rolling resistance and the best wet grip. The noise level is given by a symbol, in addition to a measured noise level, i.e. the type approval noise level at 70 km/h (for class C2 and class C3 tyres) or 80 km/h (class C1 tyres). Figure 2 shows a tyre label. One black "bar" indicates a noise level which is 3 db or more below the limit value, 2 bars a noise level 1-2 db below the limit value and 3 bars indicate a noise level on (or above) the limit. The noise limits for class C2 and C3 tyres are shown in Table 1. The tyres are subdivided in to groups. One group is the normal tyres used as steer and trailer tyres the other group is the traction tyres used as the drive tyres (see Figure 1). The note in the table caption indicates that for snow tyres, for extra load tyres and for reinforced tyres, the limits are 1-2 db higher than shown in the tables. During type approval of tyres, a measured tyre/road noise level, before comparing with the noise limit in Table 1, shall be truncated (i.e. rounded down to the nearest integer decibel value) and 1 db shall be subtracted to account for the measurement uncertainty [UNECE R117]. Thus, a noise label value is a nominal noise level. The noise level measured during the type approval testing may exceed the noise label value by up to 1.9 db. The noise levels given in the present report are measured noise levels without truncation and rounding unless it is explicitly mentioned that this has been done. Figure 2: Example of a tyre label. Side 13 af 78

17 Table 1: Noise limits for truck tyres enforced 1-Nov-12 [Reg (EC) No 661/2009]. (For special use tyres, the above limits shall be increased by 2 db. An additional 2 db shall be allowed for snow tyres in the C2 traction tyre category. For all other categories of C2 and C3 tyres, an additional 1 db shall be allowed for snow tyres. Noise limits for C3 tyres have entered into force 1-Nov-16.). Tyre class Tyre category of use Noise limit [db] C2 Normal 72 Traction 73 C3 Normal 73 Traction 75 Side 14 af 78

18 3 Method applied A sample of truck tyres representative for the Scandinavian truck tyre population has been tested. The tyres have been tested on four pavements intended to be representative for the conditions for labelling testing and for conditions similar to those at Scandinavian roads. The measurements have been carried out at a test track at the University of Twente; the Netherlands called the Twente Proving Ground (TPG). The texture, absorption and flow resistance of the surfaces have been measured in order to characterize the surfaces and their representativeness. Figure 3: Overview of Twente Proving Ground, with measurement setup near the surfaces. The measurements of the tyres have been carried out as coast-by measurements according to a procedure specified in the type approval regulation for tyres [UNECE R117]. Additional close proximity (CPX) measurements [ISO/DIS ] have been performed to identify tonal components of the tyres at the different pavements. The coast-by measurements have been analysed for each of the tyres at each of pavements. The results have been used to configure a standard heavy vehicle with a representative combination of steer, drive and trailer tyres, with the purpose of calculating the potential for reducing tyre/road noise and overall vehicle noise taking propulsion system noise into account. The potential reductions of tyre/road noise have been applied in scenarios for reduction of annoyance in Scandinavian countries. Side 15 af 78

19 3.1 Limitations Only C3 truck tyres have been dealt with in the measurements performed on TPG and in this analysis. So far only a small part of the large amount of collected data on truck tyres and truck tyre noise have been analysed in the NordTyre project and documented in the present report. The remainder of data have been stored in a database for possible further analyses. 3.2 Selected tyres The tyres selected for the measurements were tyres which were considered to contribute most to the traffic noise exposure of the population living around roads in the Nordic countries. The tyres are truck tyres (category C3) of different tyre lines and sizes, covering drive axle tyres, steering or trailing axle tyres. The terms of reference for the project [Kragh, 2013] prescribed that sets of tyres should be selected. The selection of the tyres were based on surveys on parking areas nearby Trondheim, Norway and at a custom border station between Sweden and Norway, combined with contact with e.g. truck tyre importers the survey is described in [Blokland, 2014]. When choosing the tyre, long-haul truck tyres were given priority, because they represent most of the transport work at high speed with tyre/roads noise dominating. The potentials for regional truck tyres may therefore not be covered as correct as for the long-haul truck tyres. As the majority of tyres in the Norwegian surveys were from major tyre brands, major brands were chosen in order to represent the practice of serious transport enterprises. Retreaded tyres are a significant part of the tyres in Europe: approximately 40 % in middle Europe and 65 % in Sweden and Finland [Sandberg 2012]. Retreaded tyres are used as drive and trailer tyres but not as steer tyres. A few tyres lines of the chosen tyres are therefore tested as original tyres and retreaded tyres, in order to take the retreaded tyres into account. At the same time this makes it possible to isolate the effect of the retreaded tyres. The tyre sets chosen for the project were: 8 steering, 12 drive axle (9 original, 3 retreated) and 10 trailer (6 original, 4 retreaded). The distribution of these 30 tyres is illustrated in Figure 4, and the tyres are listed in Appendix 1 together with the measured noise levels. Prior to measurements the tread band hardness, dynamic stiffness and the tread band profile of the tyres have been measured, and data describing the tyres have been recorded [Blokland, April 2015b]. Figure 4: Numbers of original and retreaded tyre sets, distributed at the different tyre types. Side 16 af 78

20 3.3 Selected pavements The consortium which performed the noise measurements selected a test track at the University of Twente, the Netherlands, for measuring coast-by noise levels from a truck using one or two sets of each selected line of truck tyres. Measuring at such a test track rather than at ordinary roads greatly enhances measurement efficiency and allows for more measurements to be performed within allocated resources. A section of the test track should comply with ISO 10844:2014 and have a mean profile depth MPD of at least 0.4 mm. The site also comprised, among other surfaces, a rough textured surface which originally was stated to be representative of SMA 16 surfaces used in Norway, Sweden and Finland [Blokland, 2014]. The ISO test surface turned out to have an MPD about 0.4 mm and thus it was slightly coarser than the minimum 0.3 mm required in ISO 10844:2014 but below its target value of 0.5 mm. The track surface texture levels exceeded the target texture spectrum levels slightly. It is unclear whether net effects on tyre/road noise should be expected as consequences of these facts [Blokland, 2015a]. According to Appendix 2, noise levels measured at the TPG SMA 11 section must be considered corresponding to noise levels on new Nordic SMA 11, and thus they are 3 4 db lower than noise levels measured on average Nordic SMA 11 and SMA 16 pavements. Besides the ISO surface and the SMA 11 there were two more surfaces on the test track: A Thin Surface Layer with 8 mm maximum aggregate size and a semi porous structure (TSL 8) A Dense Asphalt Concrete with 16 mm maximum aggregate size (DAC 16) More information on these surfaces can be seen in Appendix 2. Close up photos of the four test surfaces can be seen in Appendix 13. Here it can be seen that the ISO surface is much smoother than the SMA surface. Side 17 af 78

21 4 Noise measurements Tyre/road noise was recorded in two ways, namely by the so-called Coast-By (CB) method and by a method similar to the so-called Close-Proximity (CPX) method. Their principles are mentioned below. For details on test conditions such as vehicle speed and load, and on data recording and analysis, see [Blokland, 2015a]. Coast-By noise levels were measured while the selected vehicle was coasting past measuring microphones, i.e. rolling without having its gear box engaged and with the engine switched off. The speed of the vehicle was intended to be 70 km/h and the results are corrected to a speed of 70 km/h. The maximum A-weighted noise level L AFmax and the sound exposure level L AE was measured simultaneously on both sides of the vehicle, at a distance of 7.5 m from the vehicle centre line, at a height of 1.2 m and at 3 m, respectively. The tyre road noise was also recorded as a WAV file during the vehicle coast-down of all sections of the test track. This recording was made in a microphone position behind a front wheel, at a distance from the tyre similar to the distance standardised for CPX measurement in ISO This allowed later analysis of the level of tones relative to the level of the tyre/road noise in frequency bands around the tones, and hence attempts to determine the audibility of tones in a position close to the tyre. A picture from the measurements is shown in Figure 5. Figure 5: Measurements at Twente Proving Ground. Side 18 af 78

22 4.1 Measurement results The collected data have been stored in a MS-ACCESS data base, the structure of which is documented in [Blokland, 2015a]. It contains data on: Noise: Tyres: Test pavements: One-third octave band noise levels, overall A-weighted noise levels, maximum levels measured with time weighting F as well as sound exposure levels (L AE ) from each set of tyres on each test surface corrected to a speed of 70 km/h. No temperature correction has been applied as it is not part of the testing procedure for C3 tyres. Tyre type, line and size, and tyre tread profile, hardness and mobility. Pavement type and length of test section. L AE results in the data base must be corrected by +0.8 db in order to compensate for the short integration time necessitated by the limited lengths of the test track surfaces. The present report is mainly based on L AFmax, which correlates well with L AE, be it corrected or not. Therefore this correction is not used in this report. 4.2 Data analysis Data received from M+P were preliminarily analysed by DRD as described in the present report. Many further analyses are possible. In the preliminary data analyses, comparisons were made between: 1. Measured noise levels and EU noise limits 2. Measured noise levels and noise labels issued by tyre manufacturers 3. Noise levels from different types of tyre 4. Noise levels from original and retreaded tyre of the same tyre line Besides such comparisons, the analyses also looked at relations between measured noise levels and: 1. Labelled fuel efficiency 2. Labelled wet grip 3. Pavement type 4.3 Measured noise levels and noise limits Figure 6 shows the noise label value for each tyre which has a noise label. The figure also shows the noise limits from [Reg (EC) No 661/2009] given in Table 1. All the normal tyres (to the right) were labelled with values on or below the noise limit, while almost half of the traction tyres (to the left) were labelled with values which are higher than the noise limit! Side 19 af 78

23 Figure 6: Label values and noise limits (dotted lines) for those of the tyres which have a noise label. Figure 7 shows the noise levels measured on the TPG ISO test track and the noise limits from [Reg (EC) No 661/2009] given in Table 1. Almost all measured noise levels are higher than the limit, by up to 5.5 db, with an average difference of 2.0 db. On an average, the two lines of retreaded drive axle tyres (marked with R ) yielded almost 3 db higher noise levels than the average original drive axle tyre. For steer axle and trailer tyres this difference was 1 db. Figure 7: Noise limits and measured noise levels on the ISO test track. Data label R indicates retreaded tyre. Figure 8 shows the measured noise levels, after the subtraction of 1 db and after truncation. These noise levels on an average are 1.1 db higher than the noise limits; some noise levels are 4 db higher, while one noise level is 3 db lower than the noise limit. Side 20 af 78

24 Figure 8: Noise limits and measured noise levels on the ISO test track, after the subtraction of 1 db and after truncation. Data label R indicates retreaded tyre. The range of the noise levels measured on the ISO surface is 6 db for Drive and Steer tyres and just 1 db for the Trailer tyres whereas for the SMA surface the range is only 1 to 2 db for all three tyre types. This shows that noise levels measured at the smooth ISO surface are more sensitive to different tyre types than noise levels measured the rougher SMA surface (see Appendix 5). 4.4 Measured noise levels and tyre labels Figure 9 shows the coast-by noise level measured on the TPG ISO test track (ISO#3) for each of the selected 23 tyre lines as a function of the noise level labelled by the manufacturer. Noise levels from seven retreaded tyre lines, which have not been labelled, are not shown in the figure. The left part of the figure shows the measured noise levels, while the right part shows the measured noise levels after they have been truncated and after 1 db has been subtracted as prescribed in [UNECE R117]. The real coast-by noise levels were higher than the labelled noise levels; see the left part of Table 2, which shows the number N of tyre lines per type of tyre and the maximum, average and minimum differences between the measured coast-by level and the labelled noise level. For drive axle tyres this difference was up to 5 db, for trailer tyres up to 4.5 db and for steering tyres it was up to 6.0 db. The overall average difference was 2.6 db with a standard deviation of 1.8 db. Part of this difference is caused by the truncation and the subtraction of measurement uncertainty from the labelling test result. The right part of Table 2 shows the differences between measured noise levels, after they have been truncated and after 1 db has been subtracted according to [UNECE R117], and the noise label values. The overall average difference is 1.1 db with a standard deviation of 1.9 db. This remaining difference was explained [Blokland, 2015a] to be caused mainly by low temperatures prevailing during the NordTyre measurement series, i.e. 6 C - 11 C in combination with the absence of a temperature correction in [UNECE R117] for the C3 truck tyres. The temperature range prescribed for tyre/road noise measurements in [UNECE R117] is 5 C 40 C, with a reference temperature of 20 C. If a temperature correction of 0.05 or 0.07dB/ C, as can be found in literature, had been applied then the normalised noise levels would have been 0.7 db or 0.8 db lower [Blokland, 2015a].This would explain about 75 % of the above mentioned 1.1 db average difference 1). But as mentioned previously there is no temperature correction for C3 tyres. 1) See also notes on the representativeness of the TPG test track ISO#3 in the previous section on Selected pavements. Side 21 af 78

25 Figure 9: Coast-by noise level L AFmax measured at 1.2 m height on the TPG ISO test track (ISO#3) as a function of the noise level labelled by the manufacturer (left). Same but measured noise levels subtracted 1 db and truncated (right). Table 2: Differences between coast-by noise levels measured on the ISO test track (ISO#3) and the labelled noise levels. Position Steer Drive Trailer Steer Drive Trailer N [-] Measured noise levels Truncated and subtracted 1 db Max [db] Avg [db] Min [db] Noise levels from S, D and T tyres Drive axle tyres are noisier than trailer axle and steer axle tyres (see Figure 10). On an average the selected drive axle tyres were 4 5 db noisier than the trailer tyres and 4 db noisier than the steering tyres. Average noise levels from Trailer and Steer-tyres are almost the same, with a trend for steering tyres to be slightly noisier. Figure 10 shows the energy average of 12 measured noise levels from drive axle tyres, 9 measured noise levels from steering tyres and 11 noise levels from trailer tyres, respectively, when coasting by on each of the four pavements at the TPG. The numbers are given in Table 3. Side 22 af 78

26 Figure 10: Energy average of 12 noise levels from drive axle tyres, 9 noise levels from steer axle tyres and 11 noise levels from trailer tyres on the four pavements. Error bars show ± one standard deviation. Table 3: Energy average and standard deviations of 12 noise levels from drive axle tyres, 9 noise levels from steer axle tyres and 11 from trailer tyres on the four pavements. Tyre type Pavement ISO SMA DAC TSL Drive Drive E-avg [db] N = 12 Stdev [db] Steer N = 9 Trailer N = 11 Steer E-avg [db] Stdev [db] Trailer E-avg [db] Stdev [db] Results for the individual tyres are given in Appendices 1 and New vs retreaded tyre noise levels Even though retreaded tyres are excluded from the tyre regulation some retreaded tyres were included in the measurements performed on TPG. Figure 11 shows the coast-by noise levels measured on each of the four pavements on the TPG test track, i.e. ISO, SMA, DAC, and TSL, respectively, from the four tyre lines of which both a set of original tyres and a set of retreaded tyres were investigated. The noise level differences are given in Table 4. Noise levels from the retreaded tyres were higher than noise levels from the original tyres. The smallest difference was seen on SMA, with db higher noise levels. The average difference for all tyres on SMA was 0.3 db, while the average was 1.2 db on the other three pavements; see Table 5. This table also shows that the differences between noise levels from retreaded and original tyres were greater for the drive tyres than for the trailer tyres. L AFmax.CB Figure 11: Coast-by noise level L AFmax,CB at 1.2 m height from original and retreaded tyres on each of the four pavements. Side 23 af 78

27 Table 4: Differences between coast-by noise levels from retreaded and original tyres for each of the four pavements (colours illustrate the magnitude of the differences). Retreaded minus original [db] Pavement Tyre line Tyre position ISO SMA DAC TSL Bridgestone R109 Ecopia Trailer Michelin X Multiway 3D XDE Drive Michelin Xline Energy D Drive Michelin Xline Energy T Trailer Table 5: Average differences between coast-by noise levels from retreaded and original tyres driving of different pavements. Tyre position Pavement All tyres Drive Trailer SMA Other pavements Side 24 af 78

28 4.6 Measured noise and labelled fuel efficiency According to [EC Reg1222/2009] the fuel efficiency class shall be determined using the scale A to G given in Table 6, on the basis of the rolling resistance coefficient C r measured in as specified in UNECE Regulation No 117 and its subsequent amendments. The rolling resistance coefficient C r is calculated by dividing the rolling resistance by the load on the tyre: where C r = F r / L m (1) F r = the rolling resistance, Newton L m = the test load, kn Figure 12 and Figure 13 show the noise levels measured at the ISO and SMA 11 test track on the TPG, respectively, as a function of the labelled fuel efficiency class. The figures also show a linear regression line based on the values of C r given in the rightmost column of Table 6. The drive axle tyres had the highest rolling resistance and also yielded the highest noise levels. Table 6: Definition of fuel efficiency classes [(EC) No 1222/2009] and the C r values used in Figure 12 and Figure 13. C r [kg/t] Fuel efficiency Represented by class [-] C r [kg/t] C r 4,0 A 3.5 4,1 C r 5,0 B 4.5 5,1 C r 6,0 C 5.5 6,1 C r 7,0 D 6.5 7,1 C r 8,0 E 7.5 C r 8,1 F Empty G Side 25 af 78

29 A B C D E F Figure 12: Measured noise levels on ISO test track as a function of the labelled fuel efficiency class. A B C D E F Figure 13: Measured noise levels on SMA 11 test track as a function of the labelled fuel efficiency class. Side 26 af 78

30 4.7 Measured noise and labelled wet grip EU Commission Regulation (EU) No 1235/2011 specifies that the wet grip class of C3 tyres must be determined on the basis of the wet grip index G according to the A - G scale shown in Table 7. G = G(T) 0,03 (2) where G(T) is the wet grip index of the tyre measured in accordance with ISO 15222:2011 using Standard Reference Test Tyres (SRTT 315/70R22.5, ASTM F ). Table 7: Definition on wet grip classes A G and class midpoint values G repr of G [(EU) No 1235/2011]. G Wet grip class [-] G repr 1.25 G A G 1.24 B G 1.09 C G 0.94 D G 0.79 E 0.72 G 064 F 0.57 Empty G - Figure 14 and Figure 15 show the noise levels measured at the ISO and SMA 11 test track on the TPG, respectively, as a function of the labelled wet grip class. The figures also show linear regression lines based on the values of G repr given in the rightmost column of Table 7. Side 27 af 78

31 A F E D C B A Figure 14: Measured noise levels on the ISO test track as a function of the labelled wet grip class. F F E D C B A Figure 15: Measured noise levels on the SMA 11 test track as a function of the labelled wet grip class. Side 28 af 78

32 4.8 Relation between L AFmax and L AE Table 8 shows differences between the measured maximum noise level with time weighting F, L AFmax, and the measured noise exposure level, L AE. This difference depends on the vehicle speed and the values shown were determined at a reference speed of 70 km/h. The table shows for each section of test track the average difference and the standard deviation of differences, the maximum difference and the minimum difference between the measurement results collected at 1.2 m and 3.0 m height, respectively. All measured L AE values have been corrected by +0.8 db to account for the fact that the integration of the sound signal was limited to test sections within ±25 m from the microphone positions [Blokland 2015a]. L AE was 1 2 db higher than L AFmax, on the average. This is agreement with what was found in a recently completed part of the European project ROSANNE [Kragh, 2015], based on statistical pass-by measurements made in 2014 by the Danish Road Directorate. For multi-axle trucks and cars approximately the same relation was found between L AFmax and L AE at 1.2 m height, as given in Equation (3). L AFmax - L AE 2.7 ln(v) 13 db (3) where v is the vehicle speed in km/h. At 70 km/h this equation yields a difference of -1.5 db, i.e. approximately the same as the average differences shown in Table 8 between the noise levels measured at the TPG. The limited standard deviations of the differences imply that the potential for obtaining tyre/road noise reduction by regulating tyre use could be based either on L AFmax or on L AE -values with approximately the same outcome. Table 8: L AFmax minus L AE at 70 km/h at a microphone position of 1.2 and 3.0 m. L AE has been corrected by +0.8 db for the missing exposure from sections outside ± 25 m. Colours illustrates the magnitude of the differences. Position Diff [db] ISO SMA DAC TSL 3.0 m Max Avg Min Stdev m Max Avg Min Stdev Side 29 af 78

33 5 Potential noise reduction 5.1 Principle and Procedure Scenarios were generated by modifying the tyre/road noise component of the heavy vehicle noise and estimating the consequent changes in overall vehicle pass-by noise levels. The tyre/road noise and the propulsion noise contributions to the overall heavy vehicle noise level were calculated in the following reference cases 1) Norway and Sweden: SMA 16 pavement and 2) Denmark: SMA 11 pavement. This was done by applying the Nord2000 prediction method. To illustrate the process, Figure 16 shows the pass-by noise levels at 7.5 m distance, 1.2 m above the road surface, from a heavy vehicle on a dense asphalt concrete pavement (AC 11d) as a function of the (constant) vehicle speed, according to Nord2000. The total noise level is composed of the tyre/road noise and the propulsion system noise. If we modify the tyre/road noise by selecting another pavement or another population of tyres this will result in a change in the overall noise level. The balance between tyre/road noise and propulsion system noise depends on the sound propagation from source to receiver and hence scenarios were calculated for different propagation situations. The reason is that the tyre/road noise is emitted just over the road surface whereas the propulsion noise is emitted higher above the road surface and the source height is important for the noise propagation. Figure 16: Heavy vehicle pass-by noise level at 7.5 m as a function of the (constant) speed calculated with Nord2000 for Dense Asphalt Concrete with 11 mm maximum aggregates (AC 11d) pavement: total noise (F_Tot) and its components of tyre/road (F_Roll) and propulsion system noise (F_Prop). K:\AD\BBM\BEF\Støj\Nyttigt\Nord2000\Nord2000_referenceværdier\Nord2000_Noise reduction_spk.xls 5.2 Pavement regulation In the further analysis of the potentials for noise reductions by changing pavement types the following assumptions has been used: Norwegian SMA 16 reference pavement is replaced by SMA 8 Danish SMA 11 reference pavement is replaced by SMA 8 Side 30 af 78

34 tyre sets The same principles were applied in NordTyre Part 2 [Kragh, 2015] about the noise from passenger car tyres. SMA 16 SMA 11 SMA 8 The measurement results received from M+P, contrary to what was expected, did not contain data on truck tyre/road noise levels on SMA 16. The roughest surface at the TPG turned out to be similar to new Norwegian SMA 11 (see Appendix 2 and 3), i.e. before it has been trafficked during one winter season. In an attempt to determine how the properties of the TPG SMA 16 relate to those of Norwegian SMA 16 and Danish SMA 11 we looked at CPX measurement results obtained using reference tyres CPXH (Avon AV4) and on results of SPB measurements; see Truck tyre noise levels on SMA 16, SMA 11, and SMA Tyre regulation All the 30 truck tyres included in the TPG measurement series have been purchased on the normal tyre market in Europe and represents tyre technology available around In order to predict the potential for noise reduction if only the quietest tyres available were used, the 25 or 33 % quietest tyres have been selected and the others omitted, based on the measurement results from the ISO surface. The following regulation of truck tyre use was assumed (see the below figure): Drive tyres: Use 33 % least noisy (Omit 6 out of 9 tyre lines) Steer tyres: Use 25 % least noisy (Omit 6 out of 8 tyre lines) Trailer tyres: Use 33 % least noisy (Omit 4 out of 6 tyre lines) Figure 17: Numbers of original, original after proposed regulation and retreaded tyre sets, distributed at the different tyre types. Side 31 af 78

35 5.4 Truck configuration The effects on truck tyre noise of regulating both pavement and tyre use depend on the combination of tyres of different type, so it must be decided how to presume that a representative truck is configured, i.e. 1) its number of axles 2) the number of Steering-/Driving-/Trailer-tyres, respectively 3) the fraction of tyres which are retreaded and original tyres, respectively Figure 18 shows a 6-axle combined truck which was selected as a default truck configuration for the scenario calculations in the NordTyre project. It was assumed that there are two tyres on each axle and not four as can be found on some trucks. The numbers given in the figure are maximum possible all-up weight and axle loads given in [DTL, 2014] of a combined vehicle defined here as an articulated vehicle consisting of a motor vehicle coupled to a semi-trailer. These numbers have been issued by the Danish national trade organisation of road and railway transport industry. The following combination of tyres was decided on for a noise-wise representative truck: Motor vehicle: Steer axle: 2 original steering tyres (S) Drive axle: 2 Drive tyres (D) on one axle (50% retreaded) Trailing axle: 2 trailer tyres (T) on one axle (50% retreaded) Semitrailer: Trailing axles 6 trailer tyres (T) on 3 axles (50% retreaded) Figure 18: Representative truck configuration selected for the NordTyre scenario calculations. The numbers shown are maximum possible all-up weight and axle loads according to [DTL, 2014]. 5.5 Reduction of tyre/road noise from trucks Pavement regulation Due to the lack of data on tyre/road noise levels for SMA 8 and SMA 16 pavements in the TPG results DRD has looked for other Nordic data in order to estimate the difference in tyre/road noise levels between SMA 8, SMA 11 and SMA 16. These data are presented and analysed in Appendix 3. The overall conclusion can be seen below in Table 9. Table 9: Relative levels of tyre/road noise from a representative multi-axle truck used for this analysis. Pavement Relative noise level [db] SMA SMA 11 0 SMA Tyre regulation For representative truck with the tyre configuration as defined above the reduction of tyre/road noise has been predicted using only the 25-33% quietest tyres instead of using an average noise level of all the tyres included in the TPG measurements. See appendix 6 for figures showing further results. Side 32 af 78

36 Figure 19 shows an example of the noise level potentials for the different tyre types on the different pavements. The tyres have been ranked according to results from the TPG ISO surface. Triangles illustrate the energy average of all the noise levels from tyres of a given type measured at the ISO surface. The energy average noise level (Q_xxx) from the 25-33% quietest tyres of the type given on the x-axis, is given for each surface xxx with the ranking of tyres are based on the noise levels measured at the ISOsurface. As there s no regulation of the retreaded tyres, no quiet energy averages are illustrated for these. As seen from the figure there s a large interval for the steer and drive tyres, whereas all the trailer tyres gave similar noise levels at the ISO surface. Looking at energy averages for the quietest % tyres, it is seen that the potential reduction at the SMA surfaces is less than for the other surface types. Figure 19: Tyre noise levels at the four TPG surfaces. Vertical lines illustrate the noise level range. Triangles illustrate the energy average of the measured tyres. Q_xxx illustrate the energy average noise level from the 25-33% quietest tyres at this surface type xxx, if the sorting of the tyres were based on the xxx surface prior to regulating to the % quietest. The energy averages and reduction potentials for the tyre types, at the different surfaces based on tyre sorting at the ISO surface is illustrated in Table 10. In the weighting of the combination of original and retreaded tyres the share of retreaded tyres was set to 50 % of the drive and trailer tyres. Similar tables based on tyre sorting performed according to noise levels measured at the SMA, DAC and TSL surface, respectively, are given in Appendix 7. Side 33 af 78

37 Table 10: Energy averages and potential reduction for different tyre types at different pavements based on sorting according to ISO surface. Unit: db. ISO Surface type Drive Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New + Re-tr Quiet + Re-tr Reduction Steer Energy average ISO SMA DAC TSL All New Quiet 25% Reduction Trailer Energy average ISO SMA DAC TSL All New Quiet 33% Retread 74,5 77,3 73,6 72,1 All New + Re-tr Quiet + Re-tr Reduction Reduction potential for tyre/road noise from a truck To describe the influence of only allowing the least noisy truck tyres a present truck and a quiet truck were configured with tyres as previously described (2 Steering tyres, 2 Drive tyres and 8 Trailer tyres). 50 % retreaded tyres are used on the Drive and Trailer axles in both cases. The energy average of tyre/road noise and potential reduction from a quiet truck based on ISO sorting is illustrated in Table 11. Calculations and similar tables for sorting according to other surfaces types are illustrated in Appendix 8. The noise reduction potential for the tyre/road noise of the Quiet truck is 0.8 db for the ISO pavement 0.2 db for the SMA pavement and for the DAC and TSL pavements. In these predictions the propulsion noise is not taken into account and it must be assumed to be the same for the Present and the Quiet truck. Therefore the noise reduction including propulsion noise will be less than the level of reductions given in the table. Table 11: Energy average of tyre/road noise level of a Present and a Quiet truck, and noise reduction between the two. Sorted according to ISO pavement. Unit: db. Pavement ISO SMA DAC TSL Present truck "Quiet" truck Reduction It can be seen from the above table that the tyre/road noise from a present multi axle truck on a SMA 11 pavement is calculated to 77.5 db on the background of the TPG tyre noise measurements at a speed of 70 km/h. According to Figure 16 the tyre/road noise of a multi axle truck on an AC 11d pavement is 83.0 db when predicted by Nord2000 at 70 km/h the AC 11d is approximately 0.5 db quieter than the SMA 11. In Appendix 2 the TPG pavements are compared to typical Nordic pavements and it is concluded that the TPG SMA 11 has a noise emission that is 3-4 db lower than the noise measured at average Nordic Side 34 af 78

38 SMA 11/16 pavements. Therefore the tyre/road noise measured on TPG seems 1-2 db lower than what could be expected according to Nord2000. The present truck is equipped with two and not four tyres per axle. It must here be remarked, that the Nord2000 noise emissions has been measured around year 2000 and therefore reflect the tyre/road noise of that time period and presumably also a tendency for using four tyres per axle. 5.6 Reduction of total noise from trucks In order to weigh the total influence from reducing the truck tyre/road noise, the noise share from trucks calculated and the noise percentage share were calculated. The noise percentage share is afterwards applied to the reduction potential. As the percentage of trucks on different road types differs, the trucks are responsible for different shares of the noise at the different types of road. In appendix 9 the percentage in numbers of trucks are converted to the share in noise, and afterwards to noise reduction in db. The numbers in Table 12 are the reduction after including both propulsion and tyre/road noise (only the tyre/road noise is reduced). The columns 100 % are to illustrate the potential if the trucks were responsible for all the noise. The columns % are the actual potential, where the truck noise share is weighted. Table 12: Reduction of truck tyre noise after including propulsion noise contribution, for different road types. The columns 100 % are to illustrate the potential if the trucks were responsible for all the noise. The columns % are the actual potential, where the trucks noise share is weighted. Denmark Noise levels share: Trucks Norway Noise levels share: Trucks 100 % % 100 % % Road type db db db db Urban Highway Motorway Side 35 af 78

39 6 Annoyance scenarios Based on the potential for reducing the rolling noise from the truck tyres annoyance scenarios are developed and analysed in the following. This section describes the effects one would expect on the annoyance experienced by the populations if the noise reduction scenarios mentioned in the previous sections became reality. Based on available data on the present noise exposure of the population, changes in the value of overall noise exposure indicators to be expected as a consequence of implementing the noise reduction scenarios were calculated as described in the following. 6.1 Noise annoyance indicators In Table 13 the definitions of various noise indicators are summarised and references are given to the documents defining them. Figure 23 shows their value as a function of the noise exposure. The Danish indicator (SBT) increases exponentially with increasing noise levels while the Norwegian indicator (SPI) increases linearly, and the percentage of highly annoyed persons (%HA) following a polynomial expression increases at a rate in between those of the two other indicators. In Sweden no particular indicator is applied for aggregating noise exposure. The overall noise exposure in Sweden is expressed as the number of persons exposed to L Aeq,24h 55 db (and L Amax 70 db) [Dahlbom, 2015]. Table 13: Definitions of noise indicators used in Denmark and Norway, and the percentage of highly annoyed persons according to the EU position paper. Country Indicator / Acronym Definition Reference Denmark (DK) Noise annoyance number SBT = N dwellings G [MST no. (Støjbelastningstal) / SBT G = ( ) ] Norway (NO) Noise annoyance index SPI = N per G pvei [MCE, (Støyplageindeks) / SPI EU Percent Highly Annoyed / %HA G pvei = 1.58 (L den 39.4) %HA = (L den - 42) (L den - 42) (L den - 42) 2007] [Miedema, 2001] Figure 20: Dose response curves used for defining noise indicators in Denmark (DK) Norway (NO) and EU (Miedema) as a function of the day-evening-night noise level L den. Side 36 af 78

40 6.2 Noise mappings Denmark The results of the Danish noise mapping were reported in [Høj, 2013a] in which results of mappings made by the Danish Road Directorate and by a number of municipalities have been merged. The total number of mapped dwellings was 1.5 million, 723,000 of which were exposed to L den = 58 db or more. Tables are given in [Høj, 2013b] specifying the number of dwellings per 1 db exposure class. The results are illustrated in Figure 21, see also Appendix 12 in [Kragh, 2015]. Norway The Norwegian data extracted from the Støybygg data base were sorted by DRD into 1 db wide noise level classes. The received data cover five regions of Norway and they are complete for four of these five regions. The data contains information on 223,824 dwellings, out of which 146,728 was supplied with information on the traffic speed limit. After limiting data to noise exposures exceeding 55 db, the total number of dwellings was approximately 126,000. See Figure 21 for information on the data and their distribution and Appendix 12 in [Kragh, 2015]. Figure 21: Distribution of mapped Danish and Norwegian dwellings with L den over respectively 58 and 55 db on 1 db wide classes of noise exposure. Sweden The less detailed Swedish mapping results [Dahlbom, 2014] were not analysed further; see also Appendix 12 in [Kragh, 2015]. 6.3 Limitations Only a limited number of truck tyres are tested in this project. Scenarios are only calculated for the configured truck previously described. The retreaded tyres are not a part of the regulation, and are therefore not regulated as the new tyres. Average numbers of vehicles for certain road types are used, and the same propagation path and distance are used for all cases. 6.4 Definition of scenarios Table 14 is an attempt to illustrate the scenarios. First, the average noise reduction from the pavement types was determined, see Appendix 3, denoted x and y in Table 14. This reduced tyre/road noise level combined with the propulsion noise level gives a reduction ΔL P of the total vehicle noise level which de- Side 37 af 78

41 pend on the vehicle speed. Then the effect ΔL T on the total noise level obtained by removing all but the quietest tyres was determined, see Reduction of total noise from trucks. Finally the combined tyre/road and propulsion noise levels were determined presupposing different propagation conditions a) d) defined in Table 15. The different scenarios differ in propagation distance and weather conditions. Due to different ratios between the tyre and propulsion noise at different speeds (Figure 16) the effects of the tyre noise and pavement regulation are different. Likewise due to different height of the sources (tyre/road noise and propulsion), the influence from propagation is different. The reason for different scenarios is different calculation conditions in different countries. Figure 22 shows the balance at 80 km/h between tyre/road noise and propulsion system noise in the reference case with SMA 16. In scenarios b) and d) this balance is in practice the same. The effects of replacing the pavement or regulating the use of tyres were expressed as the change ΔL PT in overall noise level relative to the reference case on SMA 16 or SMA 11, respectively. Table 14: Illustration of noise reduction scenarios for one propagation scenario. Pavement type Avg. of all tyres With 25-33% quietest tyres Total noise reduction by replacing pavement [db] Total noise reduction by removing tyres [db] Total noise reduction [db] by pavement and tyre regulation Road type (Speed) Road type (Speed) Road type (Speed) Tyre/road noise: Effect of replacing pavement [-] [db] Urban way way ban way way ban way way High Motor- Ur- High- Motor- Ur- High- Motor- SMA 16 0 Ref Ref Ref ΔL T ΔL T ΔL T ΔL PT ΔL PT ΔL PT SMA 11 -x ΔL T ΔL T ΔL T ΔL PT ΔL PT ΔL PT SMA 8 -y ΔL T ΔL T ΔL T ΔL PT ΔL PT ΔL PT Table 15: Starting points for calculations of scenarios a) d). Pavement: SMA 16. Heavy vehicle Constant speed Air temperature (6 axles) Urban: 50 km/h Highway: 70 km/h (DK) 80km/h (NO) Motorway: 80 km/h 10 ºC a) 7.5 m from vehicle centre line; 1.2 m or 4 m above hard terrain (at SPB measurement position or dwelling close to a road); dense asphalt: flow resistivity G = 2 10 Nsm b) 100 m from vehicle centre line; 1.5 m or 4 m above terrain; no wind; 1 m hard terrain: flow resistivity G = Nsm -4 ; the rest grassland: flow resistivity D = Nsm -4 c) As b) but moderate downwind yearly average noise as used in Denmark d) As b) but moderate inversion (downward curvature): temperature gradient 1ºC/100 as used in Norway for noise mapping 7-4 Note 1: Note 2: An air temperature of 10 ºC was selected to represent a yearly average temperature. The temperature has marginal effect on the balance in Nord2000 between tyre/road noise and propulsion system noise. 4 m receiver height was chosen to represent the conditions for EU noise mapping Side 38 af 78

42 Figure 22: Calculated tyre/road noise level and propulsion system noise level at 80 km/h on SMA 16 according to Nord2000 for scenarios a) d) defined in Table 15 at an average temperature of 10 ºC. 6.5 Effect of regulation on annoyance Based on the data on population exposure to different noise level classes, the contributions from each noise level class to the overall noise indicators for the population as a whole were calculated. These calculations are described in Appendix 10. The results are illustrated in Figure 23 and the final results are given in Table 16. Figure 23 shows the contributions from each decibel class to the overall noise indicators: Støjbelastningstal (SBT), Støyplageindeks (SPI) or Number of Highly Annoyed citizens (NHA). They are all based on the Norwegian population exposure data. The examples shown are for scenario c) in the Before situation and in an After situation where Norwegian SMA 16 has been replaced by SMA 8, and using the quiet truck with the 25-33% least noisy tyres. All dwellings having L den 55.0 db in the Before situation have been included. This has also been done for SBT to enable a direct comparison of the behaviour of the indicators, even though the Danish procedure normally excludes all dwellings having L den < 58.0 db All dwellings having L den 55.0 db Before" have also been included in the After situation The assessments of the reduced annoyance made by means of the three indicators differ. SBT gives higher weight to improvements at the dwellings having the highest exposure than the two other indicators. As previous described in Reduction of total noise from trucks, does the potential has to be weighted by the share of the noise, which the trucks are responsible for. In Figure 23 the After situation is illustrated both as 100 % which is the potential if the trucks were responsible for all the noise (illustrated in petrol blue) (Hypothetical scenario), and the 24-48% which is the actual potential where the trucks noise share is weighted (illustrated in red). Side 39 af 78

43 Figure 23: Illustrations of the contributions from different noise level classes to (Top): Støjbelastningstal (SBT); Mid: Støyplageindeks (SPI); and Bottom: Number of highly annoyed persons (NHA). Based on Norwegian population exposure data and scenario c) Before and After replacing Norwegian SMA 16 by SMA 8 and using the quiet truck with the 25-33% least noisy tyres. Grey: current level; Red: reduction potential from truck tyre noise being responsible for % of total noise; Petrol blue: reduction potential from truck tyre noise being responsible for 100 % of total noise. Similar illustrations for the individual road types of the different noise indicators are illustrated in Appendix 11, for both the Danish and Norwegian situation. Table 16 shows the results of SBT-computations made for the Danish noise mapping data and SPIcomputations made for the Norwegian noise mapping data. These computations of SBT only comprise contributions from dwellings exposed to noise levels 58.0 db both before and after replacing pavements and regulating tyre noise. The computations of SPI comprise contributions from dwellings exposed to noise levels 55 db before regulation, irrespective of their noise exposure in the After situation. The Danish annoyance indicator SBT is reduced by 2 % and the Norwegian indicator is reduced by 1 %. Table 17 illustrates the influence if the trucks were responsible for all the noise. The Danish annoyance indicator SBT would be reduced by 5 % and the Norwegian indicator by 4% (Hypothetical scenario). Side 40 af 78

44 Table 16: Change ΔSBT in SBT for Denmark calculated for Scenario c) and change ΔSPI in SPI for Norway calculated for Scenario d) replacing standard pavement (SMA 11 in Denmark and SMA 16 in Norway) by SMA 8 and using the quiet truck with the 25-33% least noisy tyres. Annoyance reduction if truck tyre noise were responsible for % of the total noise actual potential, where the truck noise share is weighted. Roadtype Denmark Norway SPB ΔSPB SPI ΔSPI Before After [-] [%] Before After [-] [%] Urban 135, ,900-2, ,749 4, Highway 5,800 5, ,570 2, Motorway 14,400 14, Total 155, ,700-3, ,768 7, Table 17: Change ΔSBT in SBT for Denmark calculated for Scenario c) and change ΔSPI in SPI for Norway calculated for Scenario d) replacing standard pavement (SMA 11 in Denmark and SMA 16 in Norway) by SMA 8 and using the quiet truck with the 25-33% least noisy tyres. Annoyance reduction if truck tyre noise were responsible for 100 % of the total noise potential, where the truck noise is responsible for all the noise (Hypothetical scenario). Speed Denmark Norway SBT ΔSBT SPI ΔSPI Before After [-] [%] Before After [-] [%] Urban 135, ,300-6, ,749 4, Highway 5,800 5, ,570 2, Motorway 14,400 13,300-1, Total 155, ,000-7, ,768 7, Side 41 af 78

45 7 Tonality Truck tyres are known to sometimes generate noise having audible tonal components, which add to annoyance experienced by road neighbours. During the coast-by noise measurements a microphone near a front tyre of the truck recorded sound files [Blokland, 2015a]. From these files M+P analysed (FFT) a 1 second sample from each tyre/pavement combination and a narrow band frequency spectrum was delivered with the final report. The delivered data also included so-called Campbell diagrams illustrating the development of the narrow band frequency spectrum during coast-down over the test track; see Appendix 12. Due to the short length of each test section at TPG the recording time was approximately 1 second which must be considered very short for such analysis. Based on these Campbell diagrams DRD selected FFT spectra from tyres judged to contain clearly audible tones and spectra from tyres judged to contain little or no tonal content. These spectra were analysed by DELTA Acoustics [Thomsen 2016] using software for objective assessment of the audibility of tones in noise according to Annex C of [ISO :2007]. The audibility of a tonal component in noise is determined as the difference ΔL ta between the level of the tone(s) and the level of the masking noise in a critical band around the tone(s). Based on ΔL ta an adjustment ( penalty ) K T is determined, which according to Annex A of [ISO ] should be between 3 db and 6 db. When adding K T to the measured total noise level a so-called rating level is obtained. Even though DELTA tried to optimise tone detection settings in their analyses the overall impression is that the experiment must be considered unsuccessful. The selected combination of narrow band-width and short analysis time resulted in very ragged frequency spectra with peaks that are erroneously identified as tones. This implies that listening test would be required to verify tones, or performing analysis over a longer time with a wider bandwidth, which is not possible from the data available. Realising that it is not possible to perform tonal analysis of the data available due to the short samples, was not the only thing to note about judging the tonal components from the measurements. The measurement was performed near the tyres, whereas the audibility of tones in noise shall be judged as perceived at an emission point. This implies that judging from measurements near the tyre is on the safe side concerning tonality, where the tonal components could be reduced from the propagation from the tyres to where they are perceived. Further the tonal components would in some degree be masked from the noise from the other tyres on the truck. Adding tonal penalties to the tyres would in theory be a great idea as it annoys the neighbours, but in practice be extremely difficult/impossible as the audibility of the tones is dependent of: The propagation from the tyres to the receiver The truck configuration (all the tyres on the truck) contributing at once The surface type, where some types give raise to penalties and others not Side 42 af 78

46 8 Discussion and conclusions A truck is more complex than a passenger car, and therefore looking at the range from the noisiest tyre to the quietest is not directly the potential for reducing the noise from trucks. The results of measurements performed in this study are used to illustrate the differences between the noise levels from the truck tyre types, and the potentials for reducing traffic noise in the Nordic countries. The tyre sets chosen for the project were: 8 Steering, 12 Drive axles (9 original, 3 retreated) and 10 Trailer (6 original, 4 retreaded). The tyres have been purchased on the normal tyre market in Europe and represents tyre technology available around The measurements were performed on four pavements on the Twente test track in the Netherlands with an ISO test surface, an SMA 16 with noise levels like a new Nordic SMA 11, a Thin Surface layer (TSL) and a Dense Asphalt Concrete (DAC 16). The tyres were mounted on a truck tractor. The Coast By measurements were performed at a distance of 7.5 m with the truck coasting by at 70 km/h with the engine off. The analysis of the noise levels of the tyres illustrates big differences between labelled noise levels, and measured noise levels in this project. Dependent of the tyre type the measured noise levels are on average 2.3 to 3.1 db higher than the labelled levels. But when using the method described in UNECE R117 with up to 1 db truncation and 1 db deduction of the measurement results, the measured levels are on average 0.8 to 1.5 db higher than the labelled levels. 9 out of 17 tyres after truncation and deduction of 1 db have measured levels over the labelled levels. It can be conclude that the measured noise levels are higher than the labelled noise levels for half the tested tyres. The method described in UNECE R117 does not include a temperature correction for the C3 truck tyres and the method allow large temperature span from 5 to 40 C with a reference temperature of 20 C. The measurements at the Twente test track were performed at 6 to 11 C. If a temperature correction of 0.05 or 0.07dB/ C, as can be found in literature, had been applied then the normalised noise levels would have been 0.7 db or 0.8 db lower. This would explain about 0.7 db of the difference between measured and labelled levels. This illustrates an uncertainty in the UNECE R117 method. A typical truck is configured with steer, drive and trailer axle tyres. On average the selected Drive axle tyres were 4 5 db noisier than the Trailer axle tyres and 4 db noisier than the Steering axle tyres. Average noise levels from Trailer axle and Steering axle tyres were almost the same. The range of the noise levels measured on the ISO surface is 6 db for Drive axle and Steering axle tyres and just 1 db for the Trailer axle tyres whereas for the SMA surface the range is only 1 to 2 db for all three tyre types. This shows that noise levels at the smooth ISO surface are more sensitive to different tyre lines than at the rougher SMA surface. The measurements performed with the retreaded tyres show that the retreaded tyres were noisier than the original tyres. At the SMA surface the Drive axle tyres on an average were 0.5 db noisier than the originals, whereas the Trailer axle tyres were 0.1 db noisier. On the other surfaces the difference was larger. If the retreaded tyres were subject to regulation as the new tyres are, the potential for noise reduction would be bigger. The retreaded tyres are by 40-65% a significant part of the truck tyre population and the potential for reducing the truck tyre noise is therefore considerably limited by the retreaded tyres being noisier than the original and not being part of the labelling system. Side 43 af 78

47 A 6-axle combined truck was selected as a default truck configuration for the scenario calculations (2 Steering axle tyres, 2 Drive axle tyres and 8 Trailer axle tyres). 50 % retreaded tyres are used on the Drive and Trailer axles. The noise reduction potential of a quiet truck has been predicted if only the 25 or 33 % quietest tyres were selected and the others omitted, based on the measurement results from the ISO surface. The noise reduction potential for the tyre/road noise of the Quiet truck is 0.8 db for the ISO pavement and 0.2 db for the SMA pavement. In these predictions the propulsion noise was not taken into account, therefore the noise reduction including propulsion noise will be less. The measurements show that there are big differences on the potential noise reductions at the different surfaces, and the general picture is that the noise levels at the SMA surfaces are higher than at the other surfaces, and the range is smaller. Since the Nordic countries are mainly using SMA surfaces the potential tyre/road noise reductions from using SMA 8 pavements rather than SMA 11 and SMA 16 are bigger than the noise reductions obtained by regulating the tyre use. The potential noise reduction when changing from SMA 16 to SMA 11 is 1.3 db, and when changing from SMA 11 to SMA 8 is 0.7 db. Overall for the Nordic countries the reduction potentials are limited by the retreaded tyres not being part of the regulation and because the range of tyre noise is smaller on the typically used SMA surfaces than on the ISO surface. The measurements results have been compared to the fuel efficiency class and wet grip class for the tyres also being part of the tyre labelling system. There are tendencies towards the lower noise level the higher fuel efficiency, and the lower the noise levels the better the wet grip conditions. These tendencies are clearer for the ISO surface, than for the SMA surface, but none of the relations gives high correlation, and therefore not a strong conclusion. Scenarios for the impact of the effect on annoyance have been calculated on the background of national noise mappings of the number dwellings exposed to different noise levels. These are calculated with the configured representative truck, where the reduction potential is dominated by the retreaded tyres not being a part of the tyre noise regulation. In these calculations the propulsion noise is also taken into consideration. The potential reduction of truck noise by using only Quiet trucks and at the same time changing to SMA surfaces with smaller aggregate size was weighted by the truck share of noise at different road types. In these calculations no change in noise from passenger cars are included. The overall reduction potential for Norway and Denmark was calculated. The scenario outcome was that for Norway the SPI (Noise Annoyance Index) will be reduced by 1 %, and in Denmark the SBT (Noise Annoyance Number) will be reduced by 2 %. Despite a higher reduction resulting from the pavement regulation in Norway, the difference in annoyance indicators gives a higher percentage of noise indicator reduction for the Danish situation. The overall conclusions are that potentials for reducing the noise from truck tyres are small when investigating the influence on the Nordic road surfaces (SMA). Despite a small potential from regulating the retreaded tyres, is it problematic that the retreaded tyres are % of the truck tyre population and are not a part of the regulation. Several remarks could be given on the labelling system, but mainly that the retreaded tyres are not part of the system, that there is no temperature correction to measured label values, and for the Nordic countries that the label values measured on an ISO surface are not representative for the Nordic surface types (SMA) must be noted. As described earlier investigations of the impact of the label system on passenger car tyres were carried out in NordTyre part 1 and 2 projects. The scenarios in part 2 are similar to those in the present part 3, and a summary report on the influence from both passenger car tyres and truck tyres will be published. Side 44 af 78

48 Numerous analyses could be carried out based on the data provided for these investigations. The data could be made available for such purposes in the future, but no further analyses are planned in the NordTyre project. Side 45 af 78

49 9 References Andersen. B., Noise from heavy vehicles on thin noise reducing surfaces. Comparison of pass-by noise levels measured during , DRD Rpt 461, 2013; or Proc. Internoise 2013 Berge, T.; NordTyre Tyre/road noise testing on various road surfaces - State-of-the-Art; A22579; SIN- TEF 2012 Berge, T., personal communication to J. Kragh 2-May-16 Blokland, G. J. van, T. Berge, Tyre Selection for NordTyre Part3, Report M+P.DRD , May 2014 Blokland, G. J. van, W. Schwanen, NordTyre Part3: Results of tyre/noise measurements, Report M+P.DRD , April 2015a Blokland, G. J. van, W. Schwanen, E. van Gils, M. J. van Blokland, NordTyre Part 3: Properties of Tested Truck Tyres, Report M+P.DRD , April 2015b Blokland, G. J. van, T. Berge, NordTyre Part 3: Properties of Test Surfaces, Report M+P.DRD , May 2015c [DTL 2014], DTL Danske vognmænd, Get a good grip of heavy combined vehicles (in Danish: Få styr på de tunge vogntog), Folder issued by Danish Transport and Logistics (Dansk Transport og Logistik), trade organisation of Danish road and rail transport industry, Dahlbom, L; personal communication to J. Kragh 13-Feb-14 Høj, J., National mapping of dwellings exposed to road traffic noise in 2012 (in Danish), Arbejdsrapport fra Miljøstyrelsen nr. 5, Copenhagen 2013a, ISBN Høj, J., personal communication to J. Kragh 17-Dec-2013b ISO :2016 Acoustics -- Description, measurement and assessment of environmental noise -- Part 1: Basic quantities and assessment procedures International, International Organization for Standardization, Geneva, 2016 ISO :2007, Acoustics Description, measurement and assessment of environmental noise Part 2: Determination of environmental noise levels, International Organization for Standardization, Geneva, 2007 ISO 10844:1994, Acoustics -- Specification of test tracks for the purpose of measuring noise emitted by road vehicles, International Organization for Standardization, Geneva, 1994 ISO 10844:2014, Acoustics -- Specification of test tracks for measuring noise emitted by road vehicles and their tyres, International Organization for Standardization, Geneva, 2014 ISO/DIS , Acoustics -- Measurement of the influence of road surfaces on traffic noise -- Part 2: The close-proximity method, International Organization for Standardization, Geneva, 2014 Side 46 af 78

50 ISO :1997, Characterization of pavement texture by use of surface profiles -- Part 1: Determination of Mean Profile Depth, International Organization for Standardization, Geneva, 1997 ISO/TS :2008, Characterization of pavement texture by use of surface profiles -- Part 4: Spectral analysis of surface profiles, International Organization for Standardization, Geneva, 2008 Kragh, J., R. S. H. Skov, J. Oddershede, Report on the analysis and comparison of existing noise measurement methods for noise properties of road surfaces, ROSANNE Deliverable D2.3, 30-Apr-15, Kragh, J., NordTyre - Tyre labelling and Nordic traffic noise - 3rd Draft Final Report Analysis of data on passenger car tyres; Dok nr. 13/ ; Vejdirektoratet, June Kragh, J. NORDTYRE PART 3 TERMS OF REFERENCE TOR, Doc no 11/ att 2/13/ att. 1, Vejdirektoratet September 2013 Kragh J. et al., User's Guide Nord2000 Road, Report AV 1171/06; DELTA, 2006 MCE; Norwegian noise annoyance index (Støyplageindeks, SPI): Norwegian Ministry of Climate and Environment (MCE), Action plan against noise (in Norwegian), Handlingsplan mot støy , html?id= Miedema, H.M.E., Oudshoorn, C.G.M; Percentage of Highly Annoyed (%HA) Annoyance from transportation noise: Relation-ships with exposure metrics DNL and DENL and their confidence intervals ; Environmental Health Perspectives (109), 2001 MST no. 4; Støjkortlægning og støjhandlingsplaner; Danish Environmental Protection Agency, Denmark 2006 MST no ; Danish noise exposure number (Støjbelastningstal, SBT): Danish Environmental Protection Agency, New noise exposure number for assessing road traffic noise (in Danish), Note J.nr. MST , 5 February Nyt støjbelastningstal til vurdering af vejtrafikstøj. Regulation (EC) no 661/2009 of the European Parliament and of the Council of 13 July 2009 concerning type-approval requirements for the general safety of motor vehicles, their trailers and systems, components and separate technical units intended therefore, Published in the Official Journal of the European Union, EN , L 200/1 Regulation (EC) No 1222/2009 of the European Parliament and of the Council of 25 November 2009 on the labelling of tyres with respect to fuel efficiency and other essential parameters. Published in the Official Journal of the European Union, EN , L 342/46 Regulation (EU) No 1235/2011 of the European Parliament and the Council of 29 November 2011 amending Regulation (EC) No 1222/2009 of the European Parliament and of the Council with regard to the wet grip grading of tyres, the measurement of rolling resistance and the verification procedure. Published in the Official Journal of the European Union, EN , L 317/17 2) Sandberg, U., Proposal for a Nordic project on heavy vehicle tyre/road noise A pilot study. VTI, Final version ) defines among other things procedures for aligning measurement results obtained by different laboratories Side 47 af 78

51 Thomsen, C., Preliminary Tone Analysis of Tyre Noise According to ISO Annex C, DELTA Technical Report I101023, May 2016 UNECE Regulation R117, Uniform provisions concerning the approval of tyres with regard to tyre/road noise emissions and/or to adhesion on wet surfaces and/or to rolling resistance, revision 3; February 2014 Side 48 af 78

52 Appendixes A.1 Tyres, their labels and measured noise levels Table 18 3) gives the tyre lines, selected tyre properties and the CB noise levels at 70 km/h measured on the TPG. The noise levels are the measured results without truncation and subtraction of 1 db. The colour code used in Table 18 refers to the noise levels measured for each tyre and is as follows: < > Table 18: Tyre lines and data on their positions (Steer (S), Drive (D) or Trailer (T)), labelled fuel efficiency (RR) and wet grip class (WG); and labelled noise level, plus noise levels measured on the TPG surfaces. For further details, see [Blokland 2015b]. Noise levels Labelled Re- measured on TPG [db] Tyre line Pos. RR WG Noise tread ISO SMA DAC TSL [-] [-] [db] Bridgestone R-DRIVE 001 D C C Bridgestone R-STEER 001 S B C Bridgestone R109 Ecopia Retread T X Bridgestone R109 Ecopia T C D Continental EcoPlus HT3 T X Continental HDR2+ D E C Continental HDW2 Scandinavia D D C Continental HSR2 S C C Continental HTR2 T C C GoodYear KMAX D D C C GoodYear KMAX S S C B GoodYear KMAX T session1 T B B GoodYear KMAX T session2 T B B GoodYear Ultragrip WTS S C B GoodYear regional RHT II tread max T X Hankook AL10 e-cube session1 S C B Hankook AL10 e-cube session2 S C B Hankook DL10 e-cube D C C Michelin XFN2 AntiSplash S D C Michelin X Multiway 3D XDE REMIX D X Michelin Xline Energy D Remix D X Michelin Xline Energy T Remix T X ,9 Michelin Xline Energy Z S B B Michelin Xline Energy D D B C Michelin Xline Energy T T A B Michelin Xmulti T B B Michelin X multiway 3D XDE D D C Nokian Hakkapeliitta Truck E Set1 D E D Nokian Hakkapeliitta Truck E set2 D E D Pirelli FH:01 S B B Pirelli ST:01 neverending T B A Pneu Laurant Michelin XZE2 D X ) Note: the entire Table 18 cannot be found in a DRD.xlsx-file. Side 49 af 78

53 A.2 Test pavements and their representativity M+P consulting engineers, in their offer to perform the NordTyre measurements of truck tyre noise, had selected a test track at the University in Twente, the Netherlands, which according to the offer would provide the following pavements to perform the measurements on, quoting M+P.DRD ; VD doc- No. 13/ : According to the final report on test track surface properties, the pavements were, quoting [Blokland, 2015c] = M+P.DRD ; VD doc. No. 14/ : It is not evident that the properties of the selected test track surfaces were representative of Nordic pavements. In order to ensure such representativity of the selected pavements, as requested in the call for tenders and stated in the M+P tender, M+P recorded test track surface profiles with a laser device and measured tyre road noise levels with a CPX trailer. The test track results were compared with results of the same type of measurements carried out on representative Nordic roads. The comparisons are summarised in the following sections. A 2.1 Surface texture In Table 19 the pavement MPD values and megatexture levels L ME are given for a selection of SMA pavements while the surface texture spectra are given in Figure 24 and Figure 25. Figure 24 shows the average surface texture spectrum from the two wheel tracks of the SMA 11 section on the Twente test track (denoted Avg_TPG SMA 11 in the figure legend). The figure also shows an average texture spectrum from seven Norwegian SMA 16 pavements and one Swedish SMA 16 pavement. The error bars show plus and minus one standard deviation of the texture levels around the average level. The individual texture spectra are given in Figure 25 which is based on a data sheet received in May The average MPD values were about the same for TPG SMA 11 and the Nordic SMA 16 pavements while the average megatexture level L ME was 4 db higher on the Nordic SMA 16 pavements than on TPG SMA 11. There was a trend for the texture levels to be higher at large wavelengths on the Nordic SMA 16 pavements than on TPG SMA 11 while the opposite was the case at smaller wavelengths. Surface texture spectra from six Norwegian SMA 11 pavements showed slightly less variation between pavements than the SMA 16 data; see Figure 24 in [Blokland, 2015c]. Figure 26 shows the average texture spectrum and error bars show plus and minus one standard deviation around the average. Compared to the texture spectrum from TPG SMA 11 the texture levels at large wavelengths was 0 1 db lower on the average Norwegian SMA 11 and at small wavelengths the texture levels were 3 db lower on the average Norwegian SMA 11. Side 50 af 78

54 TPG SMA 11 Nordic SMA 16 Table 19: Selected data on pavements and their surface texture. Type Age MPD L Me Site Built Texture measured [years] [mm] [db] [year] [year] by E18 Mastemyr SINTEF E6 Trondheim SINTEF E6 Stjørdal SINTEF E22 Hörby DRD E18 Mastemyr SINTEF E6 Støren SINTEF E6 Støren SINTEF E6 Støren SINTEF SMA 16 - Average TPG East track M+P TPG West track M+P TPG - Average File: <VD. Doc. No. 14/ > Figure 24: Average surface texture spectrum of the section with SMA 11 on the Twente Test Track (TPG mean) and the average texture spectrum from the eight Nordic SMA 16 pavements. Side 51 af 78

55 Figure 25: Surface texture spectra of the two wheel tracks of the section with SMA 11 on the Twente Test Track and the texture spectra from the eight Nordic SMA 16 pavements. Figure 26: Average surface texture spectrum of the section with SMA 11 on the Twente Test Track (TPG mean) and the average texture spectrum from six Norwegian SMA 11 pavements. Side 52 af 78

56 TPG SMA M+P TPG - Avg Nordic SMA SINTEF E6 Støren Nordic SMA 16 A 2.2 CPX noise levels In Table 20 noise levels measured by SINTEF on SMA pavements on the E6 near Støren, Norway, are given together with noise levels measured by M+P on SMA 11 on the TPG, using the same set of tyres on trailers of the same type. It is unclear to the present author if the texture on these sections of E6 were similar to those dealt with in Table 19, Figure 24 and Figure 25. The noise levels measured on Norwegian SMA 16 on an average were almost 4 db higher than the noise levels measured on TPG SMA 11 both for the SRTT and Avon tyre. On 6 years old Norwegian SMA 11 they were more than 3 db higher and on new Norwegian SMA 11 they were db higher than on TPG SMA 11. Table 20: Selected data on SMA pavements and the tyre/road noise emission measured by M+P at TPG and by SINTEF on Nordic pavements. Type Age MPD L Me CPX noise level [db] Noise measured Site Built Texture measured [years] [mm] [db] SRTT Avon AV4 [year] by [year] by M+P Figure 27 shows series of CPX noise levels as a function of the pavement age, measured using SRT tyres on six sites with Danish SMA 11 pavement. At ages between 2 years and six years as in the Norwegian data in Table 20 the noise levels are between 100 db and 102 db. These numbers fit reasonably well with the Norwegian data. Noise levels marked _corr in the figure legend were measured at 110 km/h reference speed and normalised to 80 km/h using a speed correction = - 30 log (110/80). The CPX noise levels measured on the TPG SMA 11 surface are slightly lower than the (few) noise levels measured on new Danish and Norwegian SMA 11. Thus the overall result is that the noise levels measured by M+P at the TPG SMA 11 section must be considered to correspond to noise levels on New Nordic SMA 11 while the noise levels measured at the TPG SMA 11 section are 3 4 db lower than noise levels measured on average Nordic SMA 11 and SMA 16 pavements. Side 53 af 78

57 Figure 27: CPX noise levels measured in with the SRTT tyre on six Danish SMA 11 pavements as a function of the pavement age. Data labels indicate the year of measurement. Index _corr in the figure legend indicates that this series of noise levels has been corrected from 110 km/h to 80 km/h reference speed using -30 log 10 (110/80) = db. A.3 Truck tyre noise levels on SMA 16, SMA 11, and SMA 8 A 3.1 Noise Levels from SMA 16 vs. SMA 11 pavements Due to the lack of data on tyre/road noise levels on SMA 16 in the TPG results from M+P, DRD has looked at other data in order to estimate the difference in tyre/road noise levels on SMA 11 and SMA 16. A number of Norwegian data were available. CPX noise levels were measured at Støren for the NordTyre project using AVON AV4 tyres; see Table 20. The table gives a. o. data from 2-4 years old SMA 16. These noise levels on an average are 0.7 db higher than the noise levels measured on 6 years old SMA 11 pavements, also given in Table 20. Thus 2 4 years older SMA 11 seems to be quieter than 2-4 years old SMA 16. Anecdotal evidence is that after the first winter, on roads exposed to studded tyres, noise levels in Norway are 1 2 db higher than on a new pavement. Assuming an increase of 1.0 db as an effect of the first winter s traffic on both types of pavement and an increase in noise level of 0.15 db/per year, the data in Table 20 implies a 1.1 db truck tyre/road noise reduction when replacing SMA 16 by SMA 11. Data were delivered by SINTEF for the ROSANNE analysis of relations between SPB and CPX noise levels [Kragh 2015]; see Table 21. The table gives data from 8-9 years old SMA 16 and SMA 14 as well as data from new SMA 11. Surprisingly, the noise levels on SMA 14 are higher than noise levels on SMA 16, in particular the CPX noise levels, which on an average are 2.9 db higher on SMA 16 and SMA 14 than measured on new SMA 11. If one assumes a 1.0 db increase in noise level after the first winter and an increase of 0.15 db/year, the Avon AV4 data here imply 0.8 db higher levels of tyre/road noise from trucks on SMA 16 than on SMA 11 having the same age. If a 2.9 db increase in tyre/road noise is inserted in the Nord2000 model, a 2.0 db increase is found in the pass-by noise level of a multi-axle truck at 80 km/h, whereas the results in Table 21 display a slightly smaller average difference of 1.5 db. Side 54 af 78

58 Table 21: SINTEF data on SPB from heavy vehicles and CPX noise levels from Avon AV4 tyres included in the ROSANNE project. Reference speed 80 km/h Age SPB CPX Avon AV4 Site Pavement [years] [db] [db] E6 Trondheim SMA E6 Stange SMA Avg E6 Horg SMA E6 Trondheim SMA E6 Trondheim SMA E39 Øysand SMA Avg Avg. diff. [db] Measurements made in Norway on SMA 16 and SMA 11 having approximately the same age of (quote): > 2-3 years showed that pass-by noise levels from trucks at 70 km/h were approximately 0.8 db higher on SMA 16 than on SMA 11; [Berge,2016]. Based on the relation between propulsion noise and tyre/road noise in the Nord2000 model this would correspond to an increase in tyre/road noise of about 1.3 db. This is in agreement with the source part of Nord2000 which states an increase of 0.25 db per mm increase maximum aggregate size. In further data processing and analyses it has been presumed that tyre/road noise levels from multi-axle trucks are 1,3 db higher on average SMA 16 than on average SMA 11. A 3.2 Noise levels from SMA 8 vs. SMA 11 pavements The question is if any of the test sections on TPG are representative of SMA 8? The TPG ISO pavement has an MPD of 0.42 mm. The Danish SMA 8 at M4 and the SMA 8 COOEE reference surface at Steensved have MPD levels of mm. Texture levels on the SMA 8 at M4 were at least 5 db higher than on TPG ISO at wavelengths larger than 8 mm. So the TPG ISO is not representative for an SMA 8. SPB noise levels from multi-axle trucks on SMA 11 were compared with noise levels measured at a group of SMA 4 /SMA 6 /SMA 8 pavements in Denmark [Andersen, 2013]. On these groups of Danish pavements, 45 sections of road on eight sites, based on almost 7000 multi-axle truck pass-bys, SPB noise levels at 80 km/h were 0.8 db lower on average SMA with 4 8 mm max aggregate size than on SMA 11. Using the Nord2000 model this would correspond to 1.4 db rolling noise reduction, which his would probably be an overestimation due to the dominant presence of smaller aggregate sizes than 8 mm in the pavement population. The Nord2000 model for a dual-axle truck at 70 km/h on SMA 11 at 10 ºC would predict L AFmax = 79.9 db tyre/road noise level at the CB measurement position at 1.2 m height. The NordTyre average measurement results (see Table 3) from the TPG ISO test track are: 1) w/4 Drive tyres: 78.5 db; 2) w/4 Steer tyres: 74.6 db; 3) w/4 Trailer tyres: 74.1 db; which when combined to a 2-axle truck with 2 Steer, 2 Drive and 2 Trailer tyres yield L AFmax = 78.0, i.e. 1.9 db lower than on 8-9 years old Danish SMA 11. Side 55 af 78

59 Table 22 shows CPX noise levels measured in 2004 by SINTEF using the old reference tyres D for the CPX trailer method [Berge 2016]. These results indicate that tyre/road noise from trucks could be 0.7 db lower on average SMA 8 than on average SMA 11. This is in agreement with the Nord2000 model: db per mm increase in maximum aggregate size. Based on these data it has been decided that an SMA 8 has a tyre/road noise level 0.7 db lower than an SMA 11 pavement of the same age. Table 22: SINTEF CPX measurement results 2004 using reference the old tyre D representing heavy vehicle noise. File: Reference speed 50 km/h Built Age CPX_D Site Pavement [year] [years] [db] Rasta, Rv.2 SMA Vektstasjon, Rv.2 SMA Avg Rasta, Rv.2 SMA Rasta, Rv.2 SMA Skarnes, Rv.175 SMA Avg Avg. diff [db] 0.7 Side 56 af 78

60 A.4 Measured truck tyre noise levels per type of tyre The measured tyre/road noise levels of L AFmax at 1.2 m for the three different types of tyres (Steer, Drive and Trailer) are shown in Figure 28. The height of the bars shows the fraction of the given type of tyre that has a given noise level. For each tyre type the results are presented for each of the four pavements included in the TPG measurement series. Figure 28: The distribution of noise levels per type of tyre per test track pavement. Top Steer tyres, middle Drive tyres and below Trailer tyres. Side 57 af 78

61 A.5 Tyres sorted according to measurements at TPG ISO surface A 5.1 Distribution of noise level of tyre types The measured noise levels of the tyres shown in Table 18 in Appendix 1 are in the following split into tyre types and sorted according to the measurements at the ISO surface at Twente Proving Ground. The Eavg_All is the energy average of all the tyres, Quiet 25%/33% is the energy average of the 25 or 33% least noisy tyres, Eavg_Retr is the energy average of the retreaded tyres. The data in the tables below are shown for the Steer tyres (S), the Drive tyres (D) and the Trailer tyres (T). Table 23: Noise levels of steering type tyres (S), sorted according to distribution at ISO surface. Top: New tyres, Energy average of all new tyres and the of 25 % least quiet tyres. The 25 % most silent tyres are marked with light green colour. Tyre ISO SMA DAC TSL Position Retread 19 Michelin XFN2 AntiSplash S 14 GoodYear Ultragrip WTS S 11 GoodYear KMAX S S 1 Bridgestone R-STEER S 15 Hankook AL10 e-cube (avg.) 4 73,48 77,06 72,89 71,93 S 28 Pirelli FH: S 24 Michelin Xline Energy Z S 7 Continental HSR S Eavg_All Quiet 25% Reduction Double session measurements of Hankook AL10 e-cube: Tyre ISO SMA DAC TSL Position Retread 15 Hankook AL10 e-cube session S 15 Hankook AL10 e-cube session S 15 Hankook AL10 e-cube (avg.) S Side 58 af 78

62 Table 24: Noise levels of drive type tyres (D), sorted according to distribution at ISO surface. Top: New tyres, Energy average of all new tyres and the of 33 % least quiet tyres. Bottom: Retreaded tyres and energy average of all retreaded tyres. The 33 % most silent tyres are marked with light green colour. Tyre ISO SMA DAC TSL Position Retread 5 Continental HDR D 6 Continental HDW2 Scandinavia D 17 Michelin X multiway 3D XDE D 2 Bridgestone R-DRIVE D 26 Nokian Hakkapeliitta Truck E Set D 27 Nokian Hakkapeliitta Truck E set D 20 Michelin Xline Energy D D 16 Hankook DL10 e-cube D 10 GoodYear KMAX D D Eavg_All Quiet 33% Reduction Pneu Laurant Michelin XZE D R 18 Michelin X Multiway 3D XDE REMIX D R 21 Michelin Xline Energy D Remix D R Eavg_Retr, D R Table 25: Noise levels of trailer type tyres (T), sorted according to distribution at ISO surface. Top: New tyres, Energy average of all new tyres and the of 33 % least quiet tyres. Bottom: Retreaded tyres and energy average of all retreaded tyres. The 33 % most silent tyres are marked with light green colour. Tyre ISO SMA DAC TSL Position Retread 22 Michelin Xline Energy T T 8 Continental HTR T 3 Bridgestone R109 Ecopia T 12 GoodYear KMAX T (avg.) T 29 Pirelli ST:01 neverending T 25 Michelin Xmulti T Eavg_All Quiet 33% Reduction Bridgestone R109 Ecopia Retread T R 23 Michelin Xline Energy T Remix T R 13 GoodYear regional RHT II tread max T R 9 Continental EcoPlus HT T R Eavg_Retr T 5 Double session measurements GoodYear KMAX T: Tyre ISO SMA DAC TSL Position Retread 12 GoodYear KMAX T session T 12 GoodYear KMAX T session T 12 GoodYear KMAX T (avg.) T Side 59 af 78

63 A 5.2 Graphical illustration of distribution of noise levels The data in Table 23, Table 24 and Table 25 are illustrated in Figure 29, Figure 30 and Figure 31. Figure 29: Distribution of noise levels from drive tyres, sorted according to ISO surface. Dotted part is the 67% most noisy tyres, solid part is the 33% least noisy tyres. Solid point-bound part is the retreaded tyres. Figure 30: Distribution of noise levels from steering tyres, sorted according to ISO surface. Dotted part is the 75% most noisy tyres, solid part is the 25% least noisy tyres. Side 60 af 78

64 Figure 31: Distribution of noise levels from trailer tyres, sorted according to ISO surface. Dotted part is the 67% most noisy tyres, solid part is the 33% least noisy tyres. Solid point-bound part is the retreaded tyres. A.6 Noise level potentials for individual tyre types on different pavements The noise level potentials for each tyre type on the different pavements are illustrated in Figure 32 to Figure 36. The vertical lines represent the noise level range for that particular tyre type on that pavement type. The black triangles illustrate the energy average noise level measured for all tyres on that surface type. The energy average (Q_xxx) of the 25-33% quietest tyres is shown for the particular surface given on the x-axis, when ranking the tyres based on results from the xxx -surface. Only results for original tyres are illustrated in Figure 32, Figure 33 and Figure 34. Results for retreaded tyres are illustrated in Figure 35 and Figure 36. No illustrations of results for the quietest retreaded tyres have been made, since they are not part of regulation. Figure 32: Steering tyre noise levels at each of the four TPG surfaces. Vertical lines illustrate the noise level range. Triangles illustrate the energy average of the measured tyre/road noise levels. Q_xxx illustrate the energy average of the 25% quietest tyres at the surface type given on the x-axis, with the ranking of tyres based on the xxx surface prior to regulating to the 25 % quietest. Side 61 af 78

65 Figure 33: Drive tyre noise levels at each of the four TPG surfaces. Vertical lines illustrate the noise level range. Triangles illustrate the energy average of the measured tyre/road noise levels. Q_xxx illustrate the energy average of the 25% quietest tyres at the surface type given on the x-axis, with the ranking of tyres based on the xxx surface prior to regulating to the 25 % quietest. Figure 34: Trailer tyre noise levels at each of the four TPG surfaces. Vertical lines illustrate the noise level range. Triangles illustrate the energy average of the measured tyre/road noise levels. Q_xxx illustrate the energy average of the 25% quietest tyres at the surface type given on the x-axis, with the ranking of tyres based on the xxx surface prior to regulating to the 25 % quietest. Side 62 af 78

66 Figure 35: Retreaded drive axle tyre/road noise levels at the four TPG surfaces given on the x-axis. Vertical lines illustrate the noise level range. Triangles illustrate the energy average of the measured noise levels. Figure 36: Retreaded trailer axle tyre/road noise levels at the four TPG surfaces given on the x-axis. Vertical lines illustrate the noise level range. Triangles illustrate the energy average of the measured noise levels. Side 63 af 78

67 A.7 Energy average and reduction potentials for tyre types The energy average and potential reduction for the different tyre types at the different surfaces, sorted according to a certain surface. The energy averages are from Table 23, Table 24 and Table 25 in Appendix 5. As the share of retreaded tyres is approximately 50 %, is the energy average of the tyre type calculated as follows, and likewise for the quiet part weighting: E. = 10log (5) Table 26: Energy averages and potential reduction for different tyre types at different pavements based on sorting according to SMA surface. Unit: db. SMA Surface type Drive Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New+Retr Quiet + Retr Reduction Steer Energy average ISO SMA DAC TSL All New Quiet 25% Reduction Trailer Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New+Retr Quiet + Retr Reduction Side 64 af 78

68 Table 27: Energy averages and potential reduction for different tyre types at different pavements based on sorting according to DAC surface. Unit: db. DAC Surface type Drive Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New+Retr Quiet + Retr Reduction Steer Energy average ISO SMA DAC TSL All New Quiet 25% Reduction Trailer Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New+Retr Quiet + Retr Reduction Table 28: Energy averages and potential reduction for different tyre types at different pavements based on sorting according to TSL surface. Unit: db. TSL Surface type Drive Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New+Retr Quiet + Retr Reduction Steer Energy average ISO SMA DAC TSL All New Quiet 25% Reduction Trailer Energy average ISO SMA DAC TSL All New Quiet 33% Retread All New+Retr Quiet + Retr Reduction Side 65 af 78

69 A.8 Potential from truck based on different tyre sorting To represent the tyre/road noise from a truck equipped with: 2 steering tyres, 2 drive tyres and 8 trailer tyres, are the energy average calculated the following way: E, = 10log (6) This tyre configuration is a little different to Figure 1 showing two axles with drive tyres. This represents a truck using the so called super single tyres and not four tyres per axle. For the Present truck are the energy averages of the tyres denoted All New + Retr, in Appendix 7 used. For the Quiet truck are the energy averages of the tyres denoted Quiet + Retr. used. Table 29: Energy average of noise level of a Present and a Quiet truck, and noise reduction between the two. Sorted according to SMA pavement. Unit: db. SMA Surface ISO SMA DAC TSL Present truck "Quiet" truck Reduction Table 30: Energy average of noise level of a Present and a Quiet truck, and noise reduction between the two. Sorted according to DAC pavement. Unit: db. DAC Surface ISO SMA DAC TSL Present truck "Quiet" truck Reduction Table 31: Energy average of noise level of a Present and a Quiet truck, and noise reduction between the two. Sorted according to TSL pavement. Unit: db. TSL Surface ISO SMA DAC TSL Present truck "Quiet" truck Reduction A.9 Weighting the share of the total traffic noise In order to weight the influence of the truck share of the total noise in the different scenarios and road types, the following procedure is used. A 9.1 Traffic composition The traffic composition is the default traffic composition on various types of road and default traffic composition from the User s Guide Nord2000 Road [Kragh, 2006] and default Annual Average Daily Traffic (AADT) from the guidance for Noise mapping and Noise action plans in Denmark [MST no. 4, 2006] As this study is only considering the C3 tyres, the vehicle categories 2 and 3 are merged. The relevant traffic cases for the scenario calculations are illustrated in Table 32. Side 66 af 78

70 Table 32: Traffic data for the three traffic cases, annual average daily traffic(aadt) and percentage composition. Source: table 5.2, MST no. 4, Composition [%] Cat. 1 Cat. 2+3 Traffic case Description AADT Passenger cars Heavy vehicles A/B Motorway km/h / Urban motorway 60,000 85% 5+10% C Main road km/h 10,000 85% 10+5% E Urban road 50 km/h 4,000 95% 5+0% The traffic information in Table 32 is further distributed by means of the default traffic distribution on day, evening, and night on various types of roads from Table 5 in the User s Guide Nord2000 Road [Kragh, 2006]. The traffic data used in the following calculations is illustrated in Table 33. Table 33: Average traffic numbers, distributed in categories at time and traffic case. Source MST no. 4, Cat 1 Passenger cars Cat 3 Heavy vehicles Traffic case Day Evening Night Day Evening Night A/B 40,800 5,100 5,100 6, C 6, , E 3, The traffic data has been used for Nord2000 calculations of the scenarios b/d (Norwegian) and c (Danish) for the different traffic cases. The calculations have respectively been performed for the passenger cars and heavy vehicles, and the energy share of the total noise has been calculated. The shares are illustrated in Table 34. Table 34: Calculated noise levels and percentage share of noise, for Danish and Norwegian calculation scenarios with traffic distribution given in Table 33. Traffic case A C E Passenger cars Heavy Passenger cars Heavy Passenger cars Heavy Scen. DK L den [db] Share 75% 25% 50% 50% 60% 40% Scen. NO L den [db] Share 75% 25% 66% 33% 80% 20% A.10 Annoyance scenarios Similar description as in NordTyre - part 1+2 report [Kragh, 2015]. This section explains how the values of annoyance indicators given in Annoyance scenarios were determined. The basis was results of national noise mappings made in accordance with the European Directive 2002/49/EF. In 2012, noise mapping should be made for agglomerations having more than inhabitants and for roads with a traffic intensity exceeding 3 million vehicles per year. Data on dwellings exposed to L den = 55 db or more should be reported. In Denmark, though, the whole State road network was mapped, no matter the traffic intensity on the road. Side 67 af 78

71 A 10.1 Number of noise exposed dwellings Denmark The results of the Danish noise mapping were reported in [Høj, 2013] in which results of mappings made by the Danish Road Directorate and by a number of municipalities were merged. The total number of mapped dwellings was 1.5 million, 723,000 of which were exposed to 58 db or more. Tables are given in [Høj, 2013] specifying the total number of dwellings per 1 db exposure class from the lowest class 55 L den < 56 db up to the highest class 75 db. The noise levels were calculated at a height of 1.5 m above the ground. The Danish mapping results did not contain information on the speed of the traffic giving rise to the noise exposure of the dwellings. In order to be able to distinguish between different balances between tyre/road noise and propulsion system noise on roads with different traffic speed, the exposed dwellings were grouped, as an approximation, into traffic speed classes as follows: dwellings exposed to noise from municipal roads were assumed to be exposed to noise from traffic travelling at a speed of km/h, represented by 50 km/h dwellings exposed to noise from national roads (other than motorways) were assumed to be exposed to noise from traffic travelling at a speed of km/h, represented by 80 km/h dwellings exposed to noise from motorways were assumed to be exposed to noise from traffic travelling at a speed of 110 km/h The starting points were the complete table in [Høj, 2013] from the national noise mapping of dwellings in both urban and rural areas, and a corresponding table provided by the Danish Road Directorate on the exposure of dwellings along national roads. The national roads were divided into roads and motorways by a GIS count of affected dwellings along the motorway network. Actual noise contours in 5 db steps were used and the number of houses in each noise level interval was counted and subsequently converted to 1 db increments based on the table in [Høj, 2013]. The results are given in Table 35 [Høj, Dec- 2013], although only for noise level classes 58 6) 73 db and 73 db. Data on municipal roads were also delivered in noise classes up to and including 75 db. The large number of dwellings exposed to 73 db or more has important impact on some aggregate noise indicators, so the information on municipal roads was used to extrapolate data to 75 db. The extrapolation was based on the number of dwellings along municipal roads exposed to db, db and 75 db, respectively. The extrapolation result is given in Table 36. Table 35: Number of dwellings exposed to noise levels in 1 db classes along different types of road. L den [db] Municipal roads 61,542 63,922 56,795 51,351 52,943 42,705 38,594 36,997 National road, motorway 18,405 14,835 11,997 9,726 8,986 6,870 5,573 4,505 National road, other roads 3,513 2,813 2,453 2,298 2,117 2,145 1,929 1,952 All roads 83,460 81,570 71,246 63,374 64,046 51,720 46,096 43,454 L den [db] Municipal roads 36,980 32,038 27,085 27,096 27,361 19,531 15,198 13,848 National road, motorway 3,289 2,156 1,637 1, ,394 National road, other roads 1,596 1,231 1, ) The readily available table of noise exposure from the State road network did not contain data on the noise exposure classes db because only dwellings exposed to L den = 58.0 db and higher are taken into account when calculating the Danish noise indicator SBT Side 68 af 78

72 All roads 41,865 35,426 29,905 29,080 28,988 20,731 16,239 16,196 Table 36: Number of dwellings exposed to noise level classes db, db and 75 db, respectively, along different types of road, without and with extrapolation of the 73 db interval. Without extrapolation Extrapolated L den [db] Municipal roads 13,848 6,738 3,817 3,293 National road, highways 1, National road, other road All roads 16,196 7,880 4,464 3,851 Norway The Norwegian data were delivered by Statens Vegvesen, originating from the Norwegian database Støybygg. The parameter applied is UteHøyL den, i.e. the highest L den at height of 4 m at any dwelling façade. The noise levels were given with one decimal point, the lowest being 53.0 db. The Norwegian method of assessing road traffic noise, like European strategic noise maps, only requires dwellings exposed to more than 55 db to be included, and therefore data below 55 db were omitted. Data exceeding 55.0 db were sorted into 1 db wide classes. When calculating impacts of noise reduction on the noise indicators, the few data exceeding 75 db were assumed to be equal to 76 db. Data were sorted into groups according to the speed limits on the roads giving rise to the noise exposure: km/h roads were represented by 50 km/h; km/h roads were represented by 80 km/h; and km/h roads by 110 km/h, respectively. The data cover five regions of Norway and they are complete for four of these five regions, see Table 37. The received data contains information on 223,824 dwellings, out of which both speed limit and noise level information was supplied for 146,728. After limiting data to 55 db, the total number of dwellings had been reduced to 126,505. The distribution on 1 db intervals, at roads with different speed limits, is given in Table 38. Table 37: Overview of received data for Norwegian regions. Region Eastern Southern Northern Middle Western Comment Complete Complete Complete Complete Only data from Bergen and from one of three counties Side 69 af 78

73 Table 38: Number of exposed dwellings in 1 db noise level classes, distributed along roads with different speed limits. L den [db] km/h 9,622 8,905 7,853 6,982 6,212 5,466 4,749 4,154 3,763 3, km/h 4,971 4,594 4,186 3,835 3,351 3,091 2,699 2,327 2,075 1, km/h 1,008 1, Total 15,601 14,510 12,881 11,633 10,287 9,170 7,950 6,910 6,181 5,717 L den [db] km/h 3,072 2,565 2,202 2,041 1,695 1,422 1, km/h 1,750 1,458 1,244 1, km/h Total 5,057 4,218 3,600 3,234 2,605 2,150 1,622 1, L den [db] > km/h km/h km/h Total Sweden The information obtained on the Swedish results of noise mapping was supplied by Lars Dahlbom, Swedish Transport Authority (Trafikverket) [Dahlbom, 2014]. The Swedish Environmental Protection Agency (Naturvårdsverket, NV) has collected data from State roads and from 13 municipalities having more than 100,000 inhabitants, and reported data to the European Commission (COM). The data can be found on the website of COM. In view of the lack of information on traffic speed and the rough classification into 5 db wide noise level classes, it was decided not perform further analysis of the Swedish data. Swedish noise mapping is based on 1) equivalent noise levels L Aeq,24h and 2) the maximum noise level L Amax exceeded a) five times per hour during the day or b) five times during the night period. Noise levels are calculated using the Nordic prediction method for road traffic noise, version 1996, i.e. for light downwind propagation. For State roads the reporting was kept to the minimum requested by COM which means the number of inhabitants exposed to noise levels in each 5 db L den interval above 55 db. The results for the State roads were: 500,000 persons were exposed to L den 55 db along 4,000 km heavily trafficked roads. 10,000 km of road trafficked by 500 8,000 veh/24h have also been mapped with L eq24h. It was announced, that variations may exist between mapping methods applied in different regions (län). As mentioned earlier, the analysis of Swedish data was discontinued. A 10.2 Effects of regulation on the value of overall noise indicators This section gives the values of the noise indicators calculated for the situations Before and After regulating tyre/road noise. Assuming the distributions of dwellings on classes of different noise exposure given in the preceding sections, each noise indicator was calculated by accumulating the contributions from all noise level classes. For each class the noise indicator contribution was calculated by multiplying the number of dwellings or persons by the appropriate annoyance factor or fraction of annoyed persons, represented by the class midpoint noise level. Side 70 af 78

74 The results are illustrated in Appendix 11 in Figure 38 for the Danish data and in Figure 37 or the Norwegian noise exposure data. In each figure the contributions from the noise level classes to the overall accumulated noise indicator is shown as a function of the noise level. Each figure shows the contributions to the noise indicators: Støjbelastningstal (SBT), Støyplageindeks (SPI) and Number of Highly Annoyed (NHA) persons, from dwellings located at low speed (50 km/h), medium speed (80 km/h) and high speed (110 km/h) roads, respectively. In Figure 39 and Figure 40 also in Appendix 11 the contributions from each noise level class have been summarized for all three groups of traffic speed. For the Before situation these total contributions per noise level class are shown as a function of the noise level calculated in the noise mapping process. In the After situation, the noise level reductions are different for different traffic speeds and it has been chosen to show the contributions in the After situation as a function of a weighted noise level L After calculated according to Equation 7: Where where L After = L Before L Weighted (7) L Before = noise level before regulation, [db] ΔL Weighted = weighted noise reduction calculated according to Equation 8, [db] ΔL i = L Weighted = L (8) noise reduction at i = 1: low; i = 2: medium; and i = 3: high speed roads, [db] N i = number of dwellings or persons at road in group No. i, [-] N tot = total number of dwellings at all groups of road, [-] Danish data The results are illustrated in Figure 38 for the Danish data for each noise indicator for each group of traffic speed. After calculations were made for scenario c) 7) assuming that standard SMA 11 pavement is replaced by SMA 8 and using the quiet truck with the 25-33% least noisy tyres. Figure 40 shows the sum of contributions to each of the three noise indicators for the results of the Danish 2012 EU noise mapping. Norwegian data Figure 37 illustrates the results for Norwegian data. Contributions to each noise indicator are shown for each group of traffic speed. The calculations for the After situation were made for scenario d) 8 assuming that standard SMA 16 pavement is replaced by SMA 8 and that all but the tyres labelled 69 db have been removed. Contributions from dwellings exposed to noise levels 55.0 db or higher in the Before situation are included in the resulting overall value of SPI even if they are exposed to less than 55.0 db after the tyre/road noise has been regulated. In Figure 39 the sum is shown of contributions to each of the three noise indicators for the results of the Norwegian 2012 EU noise mapping. 7) The conditions used for noise mapping in Denmark 8 The conditions used for noise mapping in Norway Side 71 af 78

75 A.11 Effect of regulation on the value of overall noise indicators Figure 37: Norwegian data Illustration of impacts on Støjbelastningstallet (SBT), Støyplageindeks (SPI) and Number of highly annoyed (NHA), in different road classes for scenario d), of replacing SMA 16 by SMA 8 and regulating the tyres. Illustrations of impact of applying the total potential (100 %) to all dwellings/persons (petrol) and a weighted potential (red). Side 72 af 78

76 Figure 38: Danish data Illustration of impacts on Støjbelastningstallet (SBT), Støyplageindeks (SPI) and Number of highly annoyed (NHA), in different road classes for scenario c), of replacing SMA 11 by SMA 8 and regulating the tyres. Illustrations of impact of applying the total potential to all dwellings/persons (petrol) and a weighted potential (red). Side 73 af 78

77 Figure 39: Norwegian data Illustration of impacts on Støjbelastningstallet (SBT), Støyplageindeks (SPI) and Number of highly annoyed (NHA), for scenario d), of replacing SMA 16 by SMA 8 and regulating the tyres. Illustrations of impact of applying the total potential to all dwellings/persons (petrol) and a weighted potential (red). Figure 40: Danish data Illustration of impacts on Støjbelastningstallet (SBT), Støyplageindeks (SPI) and Number of highly annoyed (NHA), for scenario c), of replacing SMA 11 by SMA 8 and regulating the tyres. Illustrations of impact of applying the total potential to all dwellings/persons (petrol) and a weighted potential (red). Side 74 af 78

78 A.12 Tonality of track tyre noise The top part of Figure 41 shows a Campbell diagram and the bottom part of the figure shows FFT frequency spectra of the noise on each of the four test sections on the TPG. The (constant) band width is B = 1.93 Hz. Figure 42 illustrates the outcome of DELTA s objective measurement of tone audibility. The most audible tone identified is at 621 Hz and the level of the toned is ΔL ta = 22 db higher than the levels of the noise in a critical band around the tone. Attempts at batch processing the FFT-files were unsuccessful due to the very short data recording time (T = 1 s) combined with the narrow band width, yielding B T = 2. Table 39: Tyres selected for pilot measurements of the audibility ΔL ta of tones in the tyre/road noise near the tyre. File name including tyre line Tyre position Retreaded Judged as having clearly audible tone(s) based on Campbell diagram BridgestoneR-DRIVE001_27.28okt2014-run1 D BridgestoneR-DRIVE001_27.28okt2014-run2 D ContinentalHDR2_27.28okt2014-run1 D ContinentalHDR2_27.28okt2014-run2 D ContinentalHDW2Scandinavia_31okt.1nov2014-run1 D ContinentalHDW2Scandinavia_31okt.1nov2014-run2 D MichelinXlineEnergyD_31okt.1nov2014-run1 D MichelinXlineEnergyD_31okt.1nov2014-run2 D MichelinXmultiway3DXDE_27.28okt2014-run1 D MichelinXmultiway3DXDE_27.28okt2014-run2 D MichelinXMultiway3DXDEREMIX_31okt.1nov2014-run1 D x MichelinXMultiway3DXDEREMIX_31okt.1nov2014-run2 D x NokianHakkapeliittaTruckESet1_31okt.1nov2014-run2 D NokianHakkapeliittaTruckESet1_31okt.1nov2014-run2 D NokianHakkapeliittaTruckESet2_31okt.1nov2014-run1 D NokianHakkapeliittaTruckESet2_31okt.1nov2014-run2 D PneuLaurantMichelinXZE2_14.15okt2014-run1 D x PneuLaurantMichelinXZE2_14.15okt2014-run2 D x Judged as having audible but not clearly audible tone(s) based on Campbell diagram HankookAL-10e-cube_27.28okt2014-run1 S HankookAL-10e-cube_27.28okt2014-run2 S MichelinXFN2AntiSplash_14.15okt2014-run1 S MichelinXFN2AntiSplash_14.15okt2014-run2 S MichelinXlineEnergyDRemix_14.15okt2014-run1 T MichelinXlineEnergyDRemix_14.15okt2014-run2 T Side 75 af 78

79 Figure 41: Noise from a set of retreaded traction tyres. Top: Campbell diagram; Bottom: FFT spectrum of noise recorded on each test surface. Side 76 af 78

80 Figure 42: Example of the outcome of an analysis. Side 77 af 78

81 A.13 Close up photos of the four test surfaces Close up photos of the four test surfaces at the Twente Proving Ground. Figure 43: Picture of the Split Mastic Asphalt (SMA 11) surface. Blocked pattern indicate 10 x 10 mm size. Figure 44: Picture of the Dense Asphalt Concrete 16 surface (DAC 16). Blocked pattern indicate 10 x 10 mm size. Figure 45: Picture of the Thin Surface Layer (TSL 8). Blocked pattern indicate 10 x 10 mm size. Figure 46: Picture of the ISO surface. Blocked pattern indicate 10 x 10 mm size. Side 78 af 78

82 NordFoU CVR nr.: Havnegade København K