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Study Highlights Weather Conditions at Time of Motor Vehicle Crashes

Release Date: February 1, 2016

In the United States during 2010-2014, an average of 1,179,253 police-reported crashes, 425,103 injuries, and 5,137 deaths occurred in adverse weather and/or roadway surface conditions annually, representing 21% of all crashes, 18.5% of all injuries, and 15.6% of all fatalities. This is just one of the key findings of a recently published study conducted by the AAA Foundation for Traffic Safety to investigate the number of motor vehicle crashes, injuries, and deaths that occurred in relation to weather conditions and weather-related roadway surface conditions present at the time of the crash.

The majority of all crashes over the study period (86.2%) occurred in clear weather. Among crashes that did not occur in clear weather, the conditions present were crashes in rain (9.2%), snow (3.4%), sleet (0.6%), fog (0.4%), and other conditions (0.2%). Adverse weather conditions were present in 18.3% of all crashes in the Midwest and 16.8% of crashes in the Northeast, whereas they were present in only 11.6% of crashes in the South and 8.8% of crashes in the West. Crashes on Interstate highways were slightly more likely than crashes on other types of roads to occur under adverse weather conditions (18.6% vs. 13.4%) and on wet roads (17.2% vs. 14.0%). Weather conditions present in crashes of heavy trucks and buses were similar to those present in crashes of cars and light trucks.

Crashes that occurred in adverse weather or on slippery roads were more likely to be single-vehicle crashes than crashes that occurred in clear weather and on dry roads and were less likely to result in injuries or fatalities than crashes that occurred in clear weather and on dry roads. After adjustment for other factors related to crash severity, crashes that occurred on snow-covered roads resulted in 31% fewer injuries per crash and 47% fewer fatalities per crash than crashes that occurred on dry roads and crashes that occurred on ice-covered roads resulted in 19% fewer injuries per crash and 29% fewer fatalities per crash than crashes that occurred on dry roads. The only weather condition associated with a statistically elevated rate of fatalities per crash was fog-related; crashes that occurred in fog resulted in 155% more fatalities per crash than crashes that occurred in clear weather.

The AAA Foundation for Traffic Safety study Motor Vehicle Crashes, Injuries, and Deaths in Relation to Weather Conditions, United States, 2010 2014 published January 2016 can be accessed at

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The information contained in this publication was obtained from sources believed to be reliable. ISO Services, Inc., its companies and employees make no guarantee of results and assume no liability in connection with either the information herein contained or the safety suggestions herein made. Moreover, it cannot be assumed that every acceptable safety procedure is contained herein or that abnormal or unusual circumstances may not warrant or require further or additional procedure.

COPYRIGHT ©2016, ISO Services, Inc.