The influence of rear turn-signal characteristics on crash risk.

INTRODUCTION: The relationship between the relative risk of a rear-end collision during a turn, merge, or lane change maneuver and the characteristics of the rear turn-signal configuration was examined using crash data from seven states in the United States. METHOD: Rear turn-signal characteristics-including color, optics, separation, and light source-were identified for 55 vehicle models and used in a logistic regression analysis to model the odds of a rear-end collision. Additional variables including driver demographics (gender, age), vehicle age, and light condition were also modeled. Risk was assessed using a contrast group of striking vehicles in similar collisions. RESULTS: The results suggest that the odds of being the struck vehicle were 3% to 28% lower among vehicles equipped with amber versus red turn signals. Although the analysis suggests that there may be a safety benefit associated with amber rear turn signals, it is unclear whether turn-signal color alone is responsible. IMPACT ON INDUSTRY: The results suggest that aspects of a vehicle's rear signal characteristics may influence crash risk.