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Pedestrian Crash Patterns and Visibility Michael Flannagan John Sullivan Michael Sivak University of Michigan Transportation Research Institute March 14,

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Presentation on theme: "Pedestrian Crash Patterns and Visibility Michael Flannagan John Sullivan Michael Sivak University of Michigan Transportation Research Institute March 14,"— Presentation transcript:

1 Pedestrian Crash Patterns and Visibility Michael Flannagan John Sullivan Michael Sivak University of Michigan Transportation Research Institute March 14, 2007

2 Relevant reports  UMTRI  UMTRI  UMTRI  UMTRI  UMTRI  UMTRI  UMTRI

3 Vehicle occupant deaths, FARS,

4 Pedestrian deaths, FARS,

5 Pedestrians as a proportion of all road traffic fatalities

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7 Fatalities per 100,000,000 vehicle miles, U.S (National Safety Council)

8 Analysis of nighttime risks Cause of risk Worse at night Addressable by improved lighting Lightxx Alcoholx Fatiguex Etc.x

9 Isolating the effects of light in crash data  Comparing night and day is not sufficient  Differences between night and day: Ambient light Alcohol Fatigue etc.  Isolate light via seasonal and DST changes (assume exposure is linked to clock, not sun)

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14 Crash counts around fall PM return to standard time

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16 Dark/light ratios in DST data from UMTRI

17 Significant effects of light by first harmful event, FARS (UMTRI ) EventDarkLightD/L ratio Motor vehicle in transport Pedestrian Overturn Parked motor vehicle Railway train Animal

18 Estimated effects of improved (perfect) lighting UMTRI

19 The effects of natural light/darkness  When isolated from other factors that differ between night and day, the effects of light/dark are still very strong, but very specific (2,300 pedestrian fatalities per year).  For crashes that might be addressed by improved headlighting, virtually the whole story is pedestrian crashes.

20 People overdrive low beams  Perel, Olson, Sivak, & Medlin (1983): Safe speed with low beams is 70 km/h [45 mph].  Burgett, Matteson, Ulman, & Van Iderstine (1989): Maximum speed for which adequate light is achievable is 40 mph [64 km/h].

21 Pedestrian fatalities by posted speed (UMTRI )

22 Perfect lighting - potential safety benefits by road class UMTRI

23 Possible countermeasures  Pedestrian  Stay out of the way  Wear light clothes or retroreflectors  Vehicle  Better headlamps (HID, AFS, LED)  Night vision systems  Infrastructure  Separation of pedestrians (sidewalks, crosswalks)  Lighting

24 Fatal pedestrian crashes in the dark, or dark with light, by alignment (FARS 1999) AlignmentCountProportion Straight Curved Unknown7.002 Total

25 The effect of darkness by roadway alignment (DST analysis)

26 Fatal pedestrian crashes in the dark, or dark with light, by profile (FARS 1999) ProfileCountProportion Level Grade Hill crest Sag5.002 Unknown Total

27 The effect of darkness by roadway profile (DST analysis)

28 Stopping distance by initial speed (RT = 1.5 s, Braking = 0.5 g)

29 Percent of encounters with pedestrian visible, simulated (Bhise et al., 1977)

30 Recent trends in headlighting  Reports for more information  UMTRI  UMTRI  Method  2004 model year  Photometer headlamps of 20 vehicles  Include HID  25, 50, and 75 percentile light levels

31 Median Illuminance Values

32 Median Luminous Intensities

33 Halogen versus HID Headlamps

34 2004 Halogen minus 1997 Halogen

35 2004 Halogen minus 2004 HID

36 Two key low-beam test points

37 Halogen versus HID photometry


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