Traffic sign performance

Transcription

1 Traffic sign performance Andy Fish Technical Specialist 3M Traffic Safety and Security Division

2 Traffic Sign Measurement s Why is retro-reflectivity important The Language of Retro-reflectivity Practical measurements How to interpret the results

3 CONSPICUITY LEGIBILITY COMPREHENSIBILITY CREDIBILITY Traffic Sign Requirements (CIE No. 74) 3

4 CONSPICUITY LEGIBILITY COMPREHNSIBILITY CREDIBILITY Attract attention Traffic Sign Requirements (CIE No. 74) 4

5 CONSPICUITY LEGIBILITY COMPREHENSIBILITY CREDIBILITY In all conditions and relevant distances Traffic Sign Requirements (CIE No. 74) 5

6 CONSPICUITY LEGIBILITY COMPREHENSIBILITY CREDIBILITY Ease of understanding Traffic Sign Requirements (CIE No. 74) 6

7 CONSPICUITY LEGIBILITY COMPREHENSIBILITY CREDIBILITY Driver to act upon the sign Traffic Sign Requirements (CIE No. 74) 7

8 CONSPICUITY LEGIBILITY COMPREHENSIBILITY CREDIBILITY 8

9 Conspicuity CONSPICUITY Colou LEGIBILITY r Comprehensibility COMPREHENSIBILITY Credibility CREDIBILITY Contrast Colour Reflectivity Design Design Reflectivity Transmissivity Placement Placement Lighting Transmissivity Design Relevance Relevance Lighting Placement 9

10 Conspicuity and legibility Colour These are all influenced by the reflective sheeting and are controlled and measured by known standards... Contrast More on standards later Reflectivity 10

11 Retro-Reflectivity basics s

12 Retro-reflectivity basics Mirror Reflection: Diffuse Reflection: a b Retro reflection: 12

13 Retro reflectivity basics coefficient of retro reflection (of a plane retro reflecting surface) [RA] quotient of the coefficient of luminous intensity, R, of a plane retroreflective surface by its area, A Unit: cd lx-1 m-2 A measure of how much light the sign will return to the driver Candela = luminous intensity Lux= measure of illuminance 13

14 Retro reflectivity basics Observation Angle (a): a ) 14

15 Retro reflectivity basics ß Entrance Angle (ß) 15

16 Practical measurements s

17 Taking Measurements Position Orientation Geometries (TD25) 17

18 Taking Measurements Cleaning Consistency 18

19 Taking Measurements GPS data? Colour? Sign type 19

20 Interpreting The Data s

21 Interpreting The Data TD 25/15 Part 2 Inspection and maintenance of traffic signs on motorways and all-purpose trunk roads Updated in 2015 to reflect changing standards (BS EN ) 21

22 Current Standards BS EN :2007 Engineer Grad Class R3B Class R2/RA2 Engineer Grad Class RA1 22

23 Retro reflectivity basics 20 X =.33 23

24 Retro reflectivity basics 20 X =.33 24

25 Interpreting The Data Visual performance Coefficient of Retro reflection For signs constructed in accordance to BS EN the performance is only likely to be required after 7 years The coefficient of retro reflection of the white areas should be measured 25

26 Interpreting data s

27 Retro reflectivity basics RA1.33 / 5 WHITE YELLOW RED GREEN BLUE BROWN ORANGE GREY Sample Sample Sample Average reference %

28 Retro reflectivity basics RA1.33 / 5 WHITE YELLOW RED GREEN BLUE BROWN ORANGE GREY Sample Sample Sample Average reference %

29 Retro reflectivity basics RA1.33 / 5 WHITE YELLOW RED GREEN BLUE BROWN ORANGE GREY Sample Sample Sample Average reference %

30 Retro reflectivity basics RA1.33 / 5 WHITE YELLOW RED GREEN BLUE BROWN ORANGE GREY Sample Sample Sample Average reference %

31 Retro reflectivity basics RA1.33 / 5 WHITE YELLOW RED GREEN BLUE BROWN ORANGE GREY Sample Sample Sample Average reference % % of the reference value must be achieved 31

32 Retro reflectivity basics RA1.33 / 5 WHITE YELLOW RED GREEN BLUE BROWN ORANGE GREY Sample Sample Sample Average reference % RA2.33 / 5 WHITE YELLOW RED GREEN Dark Green BLUE BROWN ORANGE GREY Sample Sample Sample Average reference %

33 Summary CONSPICUITY Retro-reflective performance is important What is the purpose of the Audit? What is the material class? Attract attention 33

34 Summary LEGIBILITY Vegetation obscuring signs Faded signs Misaligned panels In all conditions and relevant distances 34

35 Questions? s