Background: Off-road vehicles (ORVs), which include all-terrain vehicles (ATVs) and side-by-sides (SxSs), are designed for off-road use only. Iowa law restricts roadway riding to occupational purposes and limits it to daylight hours. A growing number of Iowa counties are opening roadways to recreational ORV use and many counties are choosing not to include a daylight restriction. To better understand this issue, the study objective was to compare and contrast daytime and nighttime ORV crashes on Iowa’s roads. Methods: Analysis was performed using Iowa Department of Transportation crash data from 2002 to 2017 to analyze potential differences between daylight and nighttime ORV crashes. Crashes at dawn and dusk were not included in the analysis (34 crashes, 5.7% of the total). Darkness was defined as 30 minutes after sunset and ended 30 minutes before sunrise as reported by the National Weather Service. Youth were defined as <16 years of age. All analyses were performed using SPSS (Statistical Package for the Social Sciences). Results: 559 crashes were analyzed. About one-quarter (142, 25.4%) occurred in the dark, with nearly identical proportions of males and females for day vs. night crashes. The proportion of nighttime crashes was higher for adults than for youth (30% vs 11%, p<0.0001). In 48% of nighttime crashes, the vehicle operator was physically or cognitively impaired in some way (e.g. alcohol use). Impairment was only observed in 11% of drivers in daytime crashes. No child 50 mph (57% vs. 34%, p<0.0001); still, one-third of nighttime crashes occurred on roads with highway speeds. Motor vehicle crashes were more common during the day (35%) than at night (13%), p <0.001. Fatal (15%) and major (49%) injuries occurred more frequently in nighttime crashes as compared to daytime (8% fatal, 39% major), p=0.003. Conclusion: Operating ORVs on roads already represents a high-risk activity. The observation that a higher proportion of fatal and severe injuries occurred at night as compared to during the day suggests additional factors may contribute to the severity of crashes after dark. Targeted injury prevention strategies are clearly needed, including educating users about the dangers of roadway and nighttime operation, as well as better enforcement of state and local ORV safety laws.
Council on Quality Improvement and Patient Safety Program