Project Goal

This project is to better understand the most prevalent and/or risky crash types (e.g., intersection, crossing expressway) in which a pedestrian is killed and a truck is involved, and for each such crash type: the distribution of crashes as a function of different external factors (e.g., lighting condition, turning direction); the potential reasons that drivers and/or pedestrians may have failed to or not been able to avoid a crash (e.g., pedestrian was in driver’s blind spot); and the different countermeasures that might be deployed (e.g., leading pedestrian interval).

Project Summary

​In order to determine what countermeasures would be most useful at reducing pedestrian fatalities where a truck was involved, a study was undertaken using  Fatality Analysis Reporting System (FARS) data of the fatal pedestrian crashes involving a large truck which occurred between 2015 and 2020 (the study began in the fall of 2022 before the 2022 FARS data had been released).

Initially, six (largely) non-overlapping crash categories were identified:

1. Intersection
2. Crossing Expressway
3. Pedestrian Failed to Yield
4. Running/Walking Along the Roadway
5. Work Zone
6. Disabled Vehicle (the last five confined to fatalities not occurring at intersections). 

These six crash categories accounted for 68% of the crashes. 

A three step approach was then used to provide information on appropriate countermeasures for each crash type.

(a) Pattern of crashes: First, the distribution of crashes within each crash type across different external factors was examined. The external factors included: lighting condition, turning maneuver (straight through, right turn, left turn), approach direction of the pedestrian relative to the vehicle, and location of the pedestrian (e.g., travel lane).

(b) Causal factors: Second, hypotheses centered on driver and pedestrian behaviors which could potentially explain the distribution of crashes across levels of an external factor within each of the crash types were then offered and, where possible, evaluated qualitatively.

(c) Countermeasures: Third, countermeasures were suggested which addressed the causal factors and therefore could potentially reduce crashes. The countermeasures included: changes to vehicle design; adoption of advanced vehicle technologies; new infrastructure design; advanced signs, signals and pavement markings; driver and pedestrian education; and adoption of advanced pedestrian technologies (retroreflective clothing).

The major outcomes for each of the six crash categories were as follows.

1. Intersection. The pattern of crashes at intersections was consistent with the hypothesis that drivers could not see directly in front of the truck and could not see in the area of the roadway obscured by the passenger side A pillar and mirrors. Countermeasures included signals (leading pedestrian intervals, all pedestrian phasing), advanced in-vehicle technologies (bird’s eye view cameras), high vision cabs (vehicle design), and driver and pedestrian education.
2. Crossing Expressway. Police accident reports were used to supplement the information in FARS. The percentage of crashes at night in dark unlighted areas was much larger than the percentage of crashes in dark lighted areas. The crashes did not cluster. Possible countermeasures include advanced vehicle technologies such as infrared cameras so that pedestrians in the expressway could be seen at night by drivers and automatic emergency braking (AEB) coupled with pedestrian detection systems that functioned well at nighttime.
3. Pedestrian Failed to Yield. As with the crossing expressway category, the percentage of crashes at night in dark unlighted areas was much larger than the percentage of crashes in dark lighted areas. The same countermeasures would apply here as well. However, the crashes did cluster in low socioeconomic status (SES) neighborhoods. This suggests that infrastructure changes such as nighttime lighting could greatly reduce nighttime crashes.
4. Running/Walking Along the Roadway. The majority of fatal crashes occurred in dark, unlighted areas and when the pedestrian was walking/running in the same direction as the truck and hit from behind. The obvious countermeasures where possible are to run facing traffic, implicating pedestrian education, and to use advanced pedestrian technologies (e.g., retroreflective clothing).
5. Work Zone. Crashes at night when a work zone was not lighted were four times more likely than crashes at night when a work zone was lighted. This suggests that appropriate countermeasures would include advanced vehicle technologies (infrared cameras, night AEB and pedestrian detection). The presence of pop up work zones and unexpected upstream cues distant from work zone locations suggests as a countermeasure electronic logging device (ELD) warnings that can be provided by companies the enable weigh station bypass capabilities.
6. Disabled Vehicle. Crashes are much more likely in dark, unlighted conditions. This suggests as countermeasures the vehicle and pedestrian technologies discussed as well as ELD warnings which third party providers can grab from traffic centers and private companies that collect the relevant traffic information. 

In summary, the more layers of protection that are added (the more countermeasures that are included), the less likely becomes a fatal pedestrian crash involving a pedestrian. It appears from the analysis that new countermeasures together with the addition of existing countermeasures could significantly reduce such fatalities.