229024 Comparing driving exposure by driver age in Michigan

Monday, November 8, 2010

Johnathon P. Ehsani, MPH , Center for Injury Prevention among Youth, School of Public Health, University of Michigan, Ann Arbor, MI
C. Raymond Bingham, PhD , Transportation Research Institute, University of Michigan, Ann Arbor, MI
Jean T. Shope, MSPH, PhD , Transportation Research Institute, University of Michigan, Ann Arbor, MI

Motor vehicle crashes are the leading cause of death and a leading cause of morbidity among teenagers and young adults in the U.S. Understanding young driver exposure has been identified as a national priority, because exposure forms the basis of rate calculations and risk estimation. Currently, little is known about young driver exposure. This study compared two young driver groups that have a high crash risk with a low-crash-risk group of adult drivers


Using state-wide Michigan Travel Counts survey data collected in 2004 and 2005, each respondent's total miles, minutes and trips driven within a 48-hour survey period were calculated. Linear regression models tested the main effects and interactions of demographic and trip characteristic on the relationship between age and driving exposure.

Results Driving exposure patterns were distinct across the age groups. The youngest drivers drove fewer miles and minutes compared to the older age groups, and had less trip diversity, but drove a comparable number of trips. In addition, the number of vehicles per household was uniquely associated with 16-17-year-olds' exposure. Finally, the youngest drivers made a significantly higher proportion of trips with passengers, as well as a significantly higher proportion of trips with non-household passengers than older drivers.


Patterns of driving exposure differ by driver age. While it is not possible to associate these differences with crashes using these data, knowing the characteristics of young drivers spend more time driving can inform prevention efforts.

Learning Objectives:
1.Describe differences in driving exposure by age in the state of Michigan. 2.Examine how age, demographic and trip characteristics interact to influence driving exposure 3.Use driving exposure estimates to understand driving behavior patterns.

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am conducting research on young drivers as part of my doctoral degree.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.