Use of odometer readings in defining road traffic volumes and emissions

Transcription

1 Use of odometer readings in defining road traffic volumes and emissions Tuuli Järvi VTT Technical Research Centre of Finland

2 2 Use of odometer readings in defining road traffic volumes and emissions Contents Importance of road traffic mileage Present lack of knowledge in Finland Present and possible methods, pros and cons Use of odometer readings Methods Problems Comparison of results using different methods Conclusions

3 3 Why road traffic mileage is important where do we need it Emission calculations - for input to the Finnish traffic emission model LIPASTO (VTT) - to have accurate and reliable figures for total mileage by car type separately for urban and rural road network - to make a simple model of yearly car usage by car age and motive power Car fleet management model - to have a reliable sample dataset of annual car use by car age, size and motive power on county level for calibration of the new car fleet management model Statistics - also used in many other research purposes

4 4 Present lack of knowledge in Finland Total mileage by car type e.g. motive power, car size (at present only coarse vehicle type can be distinguished: car, HDV, etc.) Mileage by car age i.e. annual mileage by car type and age Urban mileage (mileage on public roads better known) Nationality of car (segregation between domestic and foreign cars) Which car and where (distribution of mileage by vehicle origin county and other counties in Finland)

5 5 Methods for measuring road traffic volumes Main methods presently used Road side traffic counts + exact information by public road type and region - no differentiation by car type only coarse vehicle types Fuel consumption + exact figures at country level - no information where the fuel is used; cars, trucks, machines, boats, others - foreign cars driving in Finland, Finnish cars driving abroad Complementary methods tested Odometer readings + exact information by any character of the vehicle (if merged with car register) - no information of road type nor geographical source of mileage (region, country) - no information about new cars < 3 years (new cars are not inspected) National and regional travel surveys (NTS) + information about the household and driver, specific questions for this purpose + origin and destination which can be geocoded (in future GPS-based systems) - not comprehensive nor reliable enough to be used alone

6 6 Methods for measuring road traffic volumes 2 Complementary methods tested cont. Automatic number plate recognition (ANPR) - advanced version of road side counting + exact information by any character of the vehicle (if merged with car register) + segregation between domestic and foreign cars - very expensive Complementary methods suggested for full picture of car mileage Mileage of foreign cars in Finland - fairly easy to survey as open land borders only from Sweden and Norway up in North where low traffic specific border crossing points between Russia and Finland with ANPR surveillance car ferry traffic from Sweden and Estonia pass through the harbours The existing Border Interview Survey (Statistics Finland) targeted at departing visitors could include questions about car use and mileage driven in Finland Mileage of Finnish cars abroad - could be collected as a part of one of the present surveys: 1. Finnish Travel Survey (Statistics Finland), continuous survey for statistics on tourism demand, 2. National Travel Survey carried out every 6th year or 3. in connection with the road worthiness tests (lacking cars < 3 years of age)

7 7 Odometer readings - usage EU Directive 2010/48/EU requires PTI centres (Periodic Technical Inspection Centres) to check odometer readings, but does not impose on Member States the obligation to collect the data and does not provide any standards for doing it Finland At present odometer readings are available only from one PTI operator in Finland, A-Katsastus Group which - is the largest in Finland with a share of 30% of inspections - has a database of odometer readings for over ten years with register numbers which enables access to the car register Our targets for usage to determine a second estimate for total mileage for calculation of the urban street mileage by subtracting the public road mileage for mileage distribution by car age and type which then will be used in the emission calculation model and calibration of the car fleet model

8 8 Odometer readings - methods For our purposes there are two ways of using the odometer readings: Longitudinal method of using time series of yearly mileage of a representative sample of individual cars of different types + reliable, precise information, possibility to detect erroneous data + transparent, easy to combine with external yearly data - needs a lot of data of several years (presently in Finland) Cross-sectional method of using differences of average cumulative mileage of cars by age and type + a simple but very coarse method + needs only recent data of one year (or even less) - conceals erroneous data and many external effects trend lines of the cross-sectional method give close to same results as the longitudinal method the cross-sectional method can be improved by use of 2-3 subsequent years and making artificial cohorts of car age groups (converges towards the longitudinal method) Note: If odometer readings are available for the whole car fleet for some years (>=3) the longitudinal method should be preferred

9 9 Odometer readings - comparing test results Figure left. Average annual kilometres per passenger car in 2008 by car age and motive power using time series of individual cars (Statistics Finland. Bossart et al. 2010) Figure left down. Average annual kilometres per passenger car in 2010 by car age and motive power using crosssectional method without cleansing Figure below. Car fleet by age and motive power in Number of passenger cars <= 20 years in use. Cars Car age, years Petrol Diesel Other

10 10 Odometer readings comparing test results 2 Total mileage of cars and average annual kilometres per car by car age and motive power Source Petrol cars Diesel cars All cars total per car total per car total per car milj. km km milj. km km milj. km km Road side counts, Odometer readings, time series, Odometer readings, cross-section, * Old cars > 30 excluded Note: Different shares of temporary decommissioned Total mileage of cars calculated using other sources Source total milj. km NTS NTS Fuel sales 2007 * AKL** * absolute maximum for cars ** Finnish Central Organisation for Motor Trades and Repairs To be noted The official figure of total mileage based on road side counts shows the highest figure, but it s accurate only for ca. 2/3 of total mileage as urban mileage is less known. Road side counts include mileage of foreign vehicles in Finland. Odometer readings include mileage driven abroad and excludes mileage of foreign vehicles in Finland.

11 11 Conclusions The cross-sectional method a simple but coarse method for calculation of average mileage by car age and motive power suits best for time independent purposes i.e. not for analysis of a specific year but e.g. for emission calculation models and forecasting can be used even after the first year of collection of odometer readings trend lines of the cross-sectional method give close to same results as the longitudinal method use of a few subsequent years and making artificial cohorts of car age groups converges towards the longitudinal method What is the main target To have a full picture of car mileage in Finland a methodology for combining all available methods to cover all elements for detailed road mileage statistics should be introduced as the Commission already has proposed the methodology should incorporate total mileage by car type and age mileage by region and segregation between urban/rural foreign cars driving in Finland, Finnish cars driving abroad

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