Urban Sprawl Puts Teen Drivers At Even Higher Risk

There is a strong relationship between the number of miles a teen drives and the risk of injury or death, said lead author Matthew Trowbridge, a fellow of the University of Michigan Injury Research Center. “So, are there things in the environment that promote driving exposure?”

Yes, according to the study, which found that teens in sprawling counties were more than twice as likely to drive more than 20 miles per day as teens in compact counties were — and the younger they were, the more miles they drove.

The study analyzed driving and demographic data for 4,528 teens, ages 16 to 19, from the 2001 National Household Transportation Survey, and then associated those data to an index of county-level sprawl to calculate the probability of a youngster racking up miles on the odometer. The researchers said that this methodology might actually underestimate the effects of sprawl on driving.

John Ulczycki, executive director of the NSC’s Transportation Safety Group, said the study gives weight to his organization’s efforts to educate parents. He said that the trend toward larger, centralized high schools requires kids to travel longer distances each day. “I suspect that, in most cases, the degree of sprawl today is much different than it was a generation ago,” he said.

Most initiatives for teen driving safety attempt to limit exposure to the risk by limiting driving. While city planners have begun to try to encourage walking and biking, they are only beginning to consider injury prevention in their designs, according to Trowbridge.

The study took a multidisciplinary approach, examining factors in the built environment that might promote driving exposure. Co-author Noreen McDonald is a professor in the Department of City and Regional Planning at the University of North Carolina.

“There’s a growing awareness that anything man-made actually impacts public health,” Trowbridge said. A key question for planners — and for all of us — he said, is, “Are we doing ourselves harm as a society with some of our development practices?”

Journal reference: Trowbridge MJ, McDonald N. Urban sprawl and miles driven daily by teenagers in the United States. Am J Prev Med 34(3), 2008.