University of Minnesota researchers have found that most aggressive drivers also tend to be hostile outside their cars.

"People don't change their behavior dramatically when they get in the car," Kathleen Harder, co-author of the study, told the St. Paul (Minn.) Pioneer Press.

She and two others administered a battery of personality, emotional and behavioral questions to a group of 710 drivers between the ages of 18 and 45.

They discovered that a group who scored as "high hostile" in the survey became "more emotionally activated while driving" than people labeled as "low hostile," Harder said.

As a group, the high-hostiles reported driving after drinking more often than the low-hostiles, taking more risks while driving and becoming angrier at slow drivers, police, discourteous drivers and road construction, she said.

Copyright 2005 by United Press International