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
2009
2010
2011
2012
3969
3338
3285
3104
3510
Annual Numbers
Occupants of motorcycles in crashes:
Year
Total People
2008
2009
2010
2011
2012
4493
3812
3741
3509
3948
Who is involved in motorcycle crashes?
2008-2011
Female
s
14%
<16
1%
21+
93%
Males
86%
Out
of
State
8%
In
State
92%
16-20
6%
Who is involved in motorcycle crashes?
2012
Female
s
14%
<16
1%
21+
93%
Males
86%
Out of
State
8%
In
State
92%
1620
6%
What About Helmet Use?
Time Period
Year(s)
Helmet Use
Rate in
Crashes
2008-2011
97%
2012
96%
2008-2011
98%
2012
74%
Jan 1-Apr 12
Apr 13-Dec 31
*74% is probably an underestimate of the true helmet
use rate on the road
Fatalities and Injuries
Apr 13-Dec 31
Year(s)
2011
2012
Serious
Fatalities Injuries
Helmet
(per
(per
Use
year)
year)
Percent
Fatal
Percent
Serious
Injury
Yes
97
574
3.2%
19%
No
6
23
7.2%
31%
Yes
56
390
2.3%
16%
No
55
194
6.5%
23%
Fatalities and Injuries
Apr 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
Driver
Passenger
Year(s)
Helmet Rate
2008-11
98%
2012
74%
2008-11
97%
2012
75%
Who Wears Helmets?
Gender
Male
Female
Year(s)
Helmet Rate
2008-11
98%
2012
73%
2008-11
97%
2012
78%
Who Wears Helmets?
Driver Drinking
Year(s)
Driver Not
Drinking
2008-11
Helmet Use
Rate
98%
2012
76%
2008-11
90%
2012
54%
Driver Drinking
Who Wears Helmets?
Category
Helmet
No Helmet
Year(s)
Percent
Riders with
Drinking
Driver
2008-11
7.1%
2012
5.2%
2008-11
30%
2012
13%
How Does Fatality Risk Change with
Alcohol and Helmet Use?
Helmet Use
Alcohol Use
Driver Drinking
Helmet Worn
Driver Not
Drinking
Driver Drinking
No Helmet
Worn
Driver Not
Drinking
Year
Percent Killed
2011
12.3%
2012
11.1%
2011
2.6%
2012
1.8%
2011
13.0%
2012
14.7%
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)