Motorcycle Safety Sampler: Michigan Crash Data - PowerPoint Presentation

1. Motorcycle Safety Sampler: Michigan Crash DataCarol Flannagan, Ph.D.University of Michigan Transportation Research InstituteMarch 20, 2019

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

3. TitleKey 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 UseApril 13, 2012 Motorcycle helmet law modification in effect

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

6. Breakdown by GroupGroupHelmet UseBefore ModificationAfter ModificationGender†(after only)Males97.4%68.6%Females97.6%71.3%Age (yrs)* <1692.1%77.0%16-2096.5%82.1%21+97.7%68.8%Seat Position Driver97.4%69.9%Passenger97.6%65.2%Vehicle Registration State*Michigan97.6%69.8%Other95.0%62.2%License Endorsement*Yes98.7%72.8%No96.3%64.3%

7. Risk factorsWith motorcycles (among others), risk factors go together:AlcoholNot wearing helmetsSpeeding

8. Risk factorsAlcohol PresenceHelmet UseBefore ModificationAfter ModificationYes89.2%42.5%No98.1%72.9%

9. Risk factorsHelmet UseFatality Rate (per Crash)Before ModificationAfter ModificationYes3.40%2.83%No6.05%6.43%Alcohol moved from mostly here:To mostly here:

10. How to think about risk factorsWearing a helmet cuts risk of fatality in half, all other things being equalBUT, fatalities have not skyrocketed (or even increased by 25%) since the modificationRisky 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. RecommendationsPromote endorsementsContinued efforts to reduce drunk cyclingPromote helmet use for drivers <21 (and recommended for others)

12. Thank you!