A study of Indiana drivers shows heightened risk of serious injury and death for men 45 and older driving on snow and ice, women driving on rain-slick highways, and younger men driving on dry roadways.

"I would say Indiana is pretty representative of the nation as a whole because it is average in terms of climate and socio-demographics, so these findings might be similar nationwide," said Fred Mannering, Purdue University's Charles Pankow Professor of Civil Engineering.

Surprisingly, men younger than 45 showed a 21 percent higher likelihood of severe injury while driving on dry roads than on wet roads, and a 72 percent higher likelihood of severe injury on a dry road than on snowy and icy roads, he said.

"Younger men may be tempering some of their aggressive driving behavior to compensate for the compromised roadway surface under adverse weather conditions," Mannering said. "But they seem to let such behavior loose on dry roads and may be underestimating the severe crash risk in good weather conditions."

Findings are based on an analysis of 2007-2008 police report crash data of 23,431 Indiana drivers.

Men 45 and older are 5.5 times more likely to be severely injured or killed when driving on snowy and icy road surfaces than they are when driving on wet surfaces.

"It's noteworthy that older men driving pickup trucks were 81 percent more likely to be injured on snow and icy surfaces than those older men driving other vehicle types," Mannering said.  "This could reflect overconfidence or a false sense of safety in such vehicles, which are generally larger."

Women 45 and older were more than four times more likely to be severely injured on wet road surfaces than when driving on dry road surfaces, and women younger than 45 were nearly three times more likely. Women in the older category also had a 44 percent higher chance of being severely injured on rain-slick interstate highways compared to other roads.

"This suggests that women drivers, on average, significantly underestimate the risk of a severe crash on wet roads and do not compensate for reduced friction on slick, high-speed roads," said Mannering, associate director for research of Purdue's Center for Road Safety.

Findings were detailed in a paper published in September in the journal Accident Analysis and Prevention. The paper was written by Mannering and doctoral student Abigail Morgan.

"The data might be used to give women drivers a heads up that they have to be really careful on wet pavements, and the same for young men on dry roads and older men on snow and ice," Mannering said. "The best way to help prevent severe accidents is understanding the conditions under which they are most likely to occur."

(Article courtesy of Purdue University News Service. View the entire article at http://www.purdue.edu/newsroom/research/2011/111205ManneringDrivers.html)