Analysis of Motorcycle Crashes: Comparison of 2012 to Previous Years

Carol A. Flannagan, Ph.D.Center for the Management of Information for Safe and

Sustainable Transportation (CMISST)Biosciences Group, UMTRI

Motorcycle Crashes

The motorcycle helmet law was modified as of April 13, 2012

What was the picture of motorcycle crashes in 2012 and how did they change (or not) compared to previous years?

Annual Numbers

Annual motorcycle crashes:

Year Total Crashes

2008 39692009 33382010 32852011 31042012 3510

Annual Numbers

Occupants of motorcycles in crashes:

Year Total People

2008 44932009 38122010 37412011 35092012 3948

Who is involved in motorcycle crashes?2008-2011

Who is involved in motorcycle crashes?2012

What About Helmet Use?

Time Period Year(s)

Helmet Use Rate in

Crashes

Jan 1-Apr 122008-2011 97%

2012 96%

Apr 13-Dec 312008-2011 98%

2012 74%

*74% is probably an underestimate of the true helmet use rate on the road

Fatalities and InjuriesApr 13-Dec 31

Year(s)Helmet

Use

Fatalities (per year)

Serious Injuries

(per year)

Percent Fatal

Percent Serious Injury

2011 Yes 97 574 3.2% 19%

No 6 23 7.2% 31%

2012 Yes 56 390 2.3% 16%

No 55 194 6.5% 23%

Fatalities and InjuriesApr 13-Dec 31

• Overall fatality rate in 2011 = 3.3%

• Overall fatality rate for 2012 = 3.4%

• Fatality rate was 2.8 times higher for those who didn’t wear helmets in 2012 compared to those who did

Who Wears Helmets?

Role Year(s) Helmet Rate

Driver 2008-11 98%

2012 74%

Passenger 2008-11 97%

2012 75%

Who Wears Helmets?

Gender Year(s) Helmet Rate

Male 2008-11 98%

2012 73%

Female 2008-11 97%

2012 78%

Who Wears Helmets?

Driver Drinking Year(s)Helmet Use

Rate

Driver Not Drinking

2008-11 98%

2012 76%

Driver Drinking 2008-11 90%

2012 54%

Who Wears Helmets?

Category Year(s)

Percent Riders with

Drinking Driver

Helmet 2008-11 7.1%2012 5.2%

No Helmet 2008-11 30%2012 13%

How Does Fatality Risk Change with Alcohol and Helmet Use?

Helmet Use Alcohol Use Year Percent Killed

Helmet WornDriver Drinking 2011 12.3%

2012 11.1%Driver Not Drinking

2011 2.6%2012 1.8%

No Helmet Worn

Driver Drinking 2011 13.0%2012 14.7%

Driver Not Drinking

2011 4.3%2012 5.3%

Separating the Effect of Alcohol from the Effect of the Helmet

How do we figure out what the helmet does separate from risk-taking factors like alcohol use?

Regression models allow us to predict risk of fatality or injury account for alcohol, speed, age, and other factors

Bottom Line…

Taking risk-taking factors into account, we find:

•Alcohol more than quadruples the risk of death and nearly triples the risk of serious injury•After accounting for other risk factors, not wearing a helmet doubles the risk of fatality and increases the risk of serious injury by 60%

Bottom Line…

If we apply the models to 2012 data and predict what would have happened if all riders had worn helmets, we would expect:

•26 fewer deaths (21% reduction)

•49 fewer serious injuries (8% reduction)

Thanks for your attention.

University of Michigan Transportation Research Institute (UMTRI)