Hazardous weather conditions and multiple-vehicle chain-reaction crashes in the United States

Motor vehicle crashes are a significant cause of death and injury worldwide, and adverse weather conditions are often a primary or underlying cause of crashes. This study focuses specifically on how weather contributes to multi-vehicle chain-reaction' crashes. Such crashes occur when a single crash halts traffic on a roadway and triggers a series of additional crashes due to motorists being unable to stop in time. Weather often contributes to such crashes by limiting visibility or making a roadway slick. By using data from the Fatality Analysis Reporting System (FARS) of the United States National Highway Traffic Safety Administration (NHTSA), this study found that more than 100 such crashes occurred between 2001 and 2012, and weather conditions were a factor in more than half of them. Radar, observations and satellite imagery were analysed for both 1 h before and 1 h after the crash to see if any diagnostic patterns were observed. Radar and observations were most useful for snow-related crashes. Dramatic increases in snow intensity and corresponding decreases in visibility were observed before most crashes. Dust-related crashes also show substantial decreases in visibility just before the crash. Satellite imagery sometimes showed plumes of dust in these cases. Meteorologists, law enforcement officials and others may find the results helpful in recognizing situations that could lead to multi-vehicle chain-reaction crashes, allowing them to take preventative action to reduce the risk of such crashes.