ANN ARBOR, Mich., Feb. 6 (UPI) -- U.S. teens in sprawling counties are twice as likely to drive more than 20 miles per day as teens in compact counties, increasing accident risk, a study said.

Lead author Matthew Trowbridge, a fellow of the University of Michigan Injury Research Center, said there is a strong relationship between the number of miles a teen drives and the risk of injury or death.

Traffic crashes are the leading cause of U.S. teen fatalities -- accounting for 44 percent -- the National Safety Council found.

The study, published in the March issue of the American Journal of Preventive Medicine, analyzed driving and demographic data for 4,528 teens, ages 16 to 19, from the 2001 National Household Transportation Survey.

The researchers associated the data to an index of county-level sprawl to calculate the probability of a teen racking up miles on the odometer and found teens living in more spread-out suburbs sprawl were more than twice as likely to drive more than 20 miles per day as teens in compact counties were.

The researchers also found and the younger the teens, the more miles they drove.