Identification of Factors Associated with Both Frequency and Severity of Deer-Related Motorcycle Crashes.

Introduction: Motorcyclists are particularly vulnerable to injury when encountering large animals such as deer in the roadway. The frequency of these events, factors associated with their occurrence, and the extent of injuries sustained from such crashes are not yet well described.

Methods: A review of 10 years (2012-2021) of statewide motorcycle crash reports from a single state with a large deer population was performed to ascertain the frequency of deer-associated motorcycle crashes. Environmental and roadway conditions, as well as motorcyclist age, gender, and helmet usage, were identified to determine if associations exist with the severity of injuries sustained.

Results: Statewide, 8.5% of reported motorcycle crashes involved deer. Excluding the two most densely populated counties, this rose to 10.7%, with 24.1% of crashes occurring during non-daylight hours being deer related. Factors associated with increased frequency of more severe injury and death included not wearing a helmet, female gender, and rural county crash location. Death and severe injuries were reported in more than twice as many riders who were unhelmeted compared to those wearing helmets (36.1 vs 16.6%; p < 0.01).

Conclusion: In a single midwestern state, deer represent a significant danger to motorcyclists, especially in rural settings during non-daylight hours. A cautious approach to riding during this time, utilizing available safety precautions to minimize risk of severe injury and death, and further exploration of viable interventions to reduce the likelihood of these occurrences should be considered.