Motorcycle Safety Sampler: Michigan Crash Data

1. Motorcycle Safety Sampler: Michigan Crash Data Carol Flannagan, Ph.D. University of Michigan Transportation Research Institute March 20, 2019

2. Motorcycle Crashes and the Helmet Law • Helmet law was modified starting April 13, 2012 • Helmets no longer required for motorcyclists age 21+ • Six years of data now—what can we learn/conclude?

3. Title • Key results: • In the crash population, helmet use dropped from 98% in 2008-2011 to 74% in 2012 after modification of the helmet law. The rate was just below 70% in 2017. In general, the helmet use rate observed in crashes has been decreasing very slowly since the large decrease after the modification. • Before and after the modification, the percentage of out-of-state riders who were involved in Michigan crashes has remained stable at ~6%. • Helmet use rates for crash-involved riders age 16-20 dropped from 96% before the modification to 83% in 2017, even though helmet use is mandatory for the riders in this age group. • Motorcycle drivers without motorcycle endorsements are somewhat less likely to wear a helmet, compared to those with endorsements. Those with endorsements made up 55% of the population both before and after the modification. • After accounting for other risk factors (e.g., alcohol involvement), the risk of fatality for non-helmeted riders was 1.9 times the risk for helmeted riders. Non-helmeted riders’ risk of serious injury was 1.7 times higher than that of helmeted riders. • The overall rate of K+A injuries (per crash-involved rider) decreased from 21% before the modification to 18% after. However, the fatality rate per crash-involved rider increased from just over 3% in 2010-2011 to just over 4% in 2015-2017. • Regression models were used to estimate the number of fatalities and serious injuries attributable to changes in helmet use since the modification. Based on these models, 19% (23 per year) of fatalities and 12% (77 per year) of serious injuries were estimated to have resulted from reduced helmet use after the helmet-law modification.

4. Basic trends: Helmet Use April 13, 2012 Motorcycle helmet law modification in effect

5. Basic trends: Fatalities April 13, 2012 Motorcycle helmet law modification in effect

6. Breakdown by Group

7. Risk factors With motorcycles (among others), risk factors go together: • Alcohol • Not wearing helmets • Speeding

8. Risk factors

9. Risk factors Alcohol moved from mostly here: To mostly here:

10. How to think about risk factors • Wearing a helmet cuts risk of fatality in half, all other things being equal • BUT, fatalities have not skyrocketed (or even increased by 25%) since the modification • Risky motorcyclists (alcohol and speeding) in fatal crashes may have died anyway even when wearing a helmet (because of the severity of the crash) • But, other states see continuing decline in helmet use over time, and increase in fatalities is happening now and probably will continue

11. Recommendations • Promote endorsements • Continued efforts to reduce drunk cycling • Promote helmet use for drivers <21 (and recommended for others)

12. Thank you!