To reduce traffic fatalities through vehicle safety measures, particular
attention must be given to cyclist-related fatalities. Clarifying the
characteristics of hazardous events leading to cyclist fatalities, not only by
vehicle speed range but also by vehicle type, is essential and should be based
on analyses of real-world accident data. Accordingly, this study aimed to
characterize fatal cyclist accidents involving vehicles traveling at low and
high speeds in Japan. We used macro accident data from the Japanese Institute
for Traffic Accident Research and Data Analysis covering the period from 2013 to
2022. Based on nine vehicle types, we investigated the effects of road type,
vehicle behavior, and accident type on cyclist fatalities. Additionally, we
identified the five most frequent accident scenarios separately for each low-
and high-speed category. At signalized intersections, the proportions of cyclist
fatalities involving vehicles traveling at low speeds were higher than those
involving vehicles traveling at high speeds across all vehicle types. In
contrast, on straight roads, the proportions at low speeds were lower than those
at high speeds for all vehicle types. In the low-speed range, cyclist fatalities
within the top five scenarios accounted for 65% of all fatalities, with the most
frequent scenario occurring at signalized intersections during left-turn
maneuvers, where heavy-duty trucks accounted for 86% of the fatalities. In the
high-speed range, cyclist fatalities within the top five scenarios accounted for
71% of all fatalities. The most frequent high-speed scenario involved crossing
collisions at unsignalized intersections when vehicles traveled straight, with
light passenger cars and sedans accounting for 29% and 24% of the fatalities,
respectively. These findings provide valuable insights for the development of
targeted traffic safety regulations and vehicle technologies aimed at reducing
vehicle–cyclist collisions across different speed ranges.
