Background
Motorcycle-deer collisions have been described in several small case series. Risk factors for motorcycle-deer collisions and opportunities for intervention have yet to be described.
Objective
The aim of this case-control study is to determine risk factors associated with fatal and injury-related motorcycle-deer collisions.
Methods
The study group was created from Michigan State Police reports and were abstracted from the Michigan Traffic Crash Facts Database for motorcycle-deer collisions occurring from 2004 to 2011 (n = 2692).
Results
A total of 50 fatal (1.9%) and 2642 nonfatal (98.1%) collisions were reported during the study period. Persons involved in fatal collisions were older than those in nonfatal collisions (54.3 vs 44.3, P = .028). Injury severity was evenly distributed (20.3% incapacitating, 31.7% nonincapacitating, 22.2% possible injury, and 25.8% not injured). Transfer to hospital was highest among persons with incapacitating injury (90.7%), fatalities (68%), and nonincapacitating injury (63.7%). Among persons transported to the hospital, helmet use was significantly less for fatal collisions (P = .0009). Motorcycle damage was significantly greater among fatal crashes (P < .0001). Swerving to avoid a crash resulted in higher proportions of nonincapacitating injury but zero fatalities (P < .0001). The majority of collisions (80%) occurred between June and October. November saw a higher proportion of fatal crashes (12% vs 4%, P = .004). The highest risk time of day for all collisions was between 5:00
Conclusions
Fatal motorcycle-deer collisions were more likely to involve older persons, less helmet usage, and do more damage to the motorcycle. Swerving to avoid collision may prevent a fatal crash. Opportunities for intervention should focus on limiting deer access to roadways and increasing safe driving practices.