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

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

Vehicle occupant deaths, FARS,

Pedestrian deaths, FARS,

Pedestrians as a proportion of all road traffic fatalities

Fatalities per 100,000,000 vehicle miles, U.S (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)

Crash counts around fall PM return to standard time

Dark/light ratios in DST data from UMTRI

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

Estimated effects of improved (perfect) lighting UMTRI

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 )

Perfect lighting - potential safety benefits by road class UMTRI

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 Straight Curved Unknown7.002 Total

The effect of darkness by roadway alignment (DST analysis)

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

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  UMTRI  Method  2004 model year  Photometer headlamps of 20 vehicles  Include HID  25, 50, and 75 percentile light levels

Median Illuminance Values

Median Luminous Intensities

Halogen versus HID Headlamps

2004 Halogen minus 1997 Halogen

2004 Halogen minus 2004 HID

Two key low-beam test points

Halogen versus HID photometry