Task 1 Report for the National Highway Traffic Safety Administration: Identification and trade study analysis of alternative rear signaling systems

Rear-end crashes are the most frequently occurring type of collision, accounting for approximately 29% of all crashes and resulting in a substantial number of injuries and fatalities each year. Rear-end collisions in which the lead vehicle is stopped or moving very slowly prior to the crash account for the majority of these accidents. Over the years several initiatives have addressed the problem of rear-end crashes, with limited success. The most public of these ventures was the center high-mounted stop lamp (CHMSL), which was required to be present on automobiles beginning with model year 1986. The long-term effectiveness of the CHMSL has leveled off at about a 4% effectiveness in preventing rear-end crashes, which means there is still much room for improvement. The goal of this research effort is to develop and test a small number of enhanced rear-lighting concepts that have the potential to reduce the number of rear-end collisions. These are to include problems with stopped vehicles. This report encompasses the first task of the research effort. Task 1 involved investigating all previous efforts to develop enhanced rear-lighting systems, determining the causes of rear-end crashes, and developing a short list of rear-lighting alternatives to be tested in future research efforts under this project. The literature review revealed that numerous rear-lighting systems have been proposed over the past 30 years. Focus groups conducted with law enforcement officers found that the most common cause of rear-end crashes is driver inattention and distraction, with following too closely as the next most common cause. A review of several crash database analyses revealed similar results, as did a study in which drivers of striking vehicles were interviewed. The final subtask was to conduct a trade study to suggest two to three rear-lighting concepts for further study. An expert panel consisting of twelve rear-lighting experts was assembled. The trade study was conducted electronically (email) via a series of three questionnaires. This process resulted in the recommendation of three rear-lighting configurations for further refinement. Algorithms for the activation and deactivation of these systems were also developed during Task 1.