Presentation on theme: "Pedestrian Crash Patterns and Visibility Michael Flannagan John Sullivan Michael Sivak University of Michigan Transportation Research Institute March 14,"— Presentation transcript:
Pedestrian Crash Patterns and Visibility Michael Flannagan John Sullivan Michael Sivak University of Michigan Transportation Research Institute March 14, 2007
Fatalities per 100,000,000 vehicle miles, U.S. 2003 (National Safety Council)
Analysis of nighttime risks Cause of risk Worse at night Addressable by improved lighting Lightxx Alcoholx Fatiguex Etc.x
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)
Dark/light ratios in DST data from UMTRI-2001-33
Significant effects of light by first harmful event, FARS 1987-1997 (UMTRI-2001-33) EventDarkLightD/L ratio Motor vehicle in transport145410911.33 Pedestrian11472774.14 Overturn1742390.73 Parked motor vehicle38182.11 Railway train35181.94 Animal2354.60
Estimated effects of improved (perfect) lighting UMTRI-2001-33
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.
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].
Pedestrian fatalities by posted speed (UMTRI-2006-1)
Perfect lighting - potential safety benefits by road class UMTRI-2001-33
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
Fatal pedestrian crashes in the dark, or dark with light, by alignment (FARS 1999) AlignmentCountProportion Straight2905.944 Curved165.054 Unknown7.002 Total30771.000
The effect of darkness by roadway alignment (DST analysis)
Fatal pedestrian crashes in the dark, or dark with light, by profile (FARS 1999) ProfileCountProportion Level2469.802 Grade502.163 Hill crest39.013 Sag5.002 Unknown62.020 Total30771.000
The effect of darkness by roadway profile (DST analysis)
Stopping distance by initial speed (RT = 1.5 s, Braking = 0.5 g)
Percent of encounters with pedestrian visible, simulated (Bhise et al., 1977)
Recent trends in headlighting Reports for more information UMTRI-2004-23 UMTRI-2004-25 Method 2004 model year Photometer headlamps of 20 vehicles Include HID 25, 50, and 75 percentile light levels
Your consent to our cookies if you continue to use this website.