Comparing driving exposure by driver age in Michigan

Background

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

Methods

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.

Conclusion

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.