ANN ARBOR—Although men still account for most alcohol-related automobile crashes, women comprise an increasing proportion of drivers involved in drinking and driving accidents, say University of Michigan researchers.

“While there has been an overall decrease in both the rate and the incidence of alcohol-related driving, the changes that are occurring appear to differ by gender,” says Patricia F. Waller, director of the U-M Transportation Research Institute (UMTRI). ” Alcohol appears to have greater effects on females in terms of biomedical damage and impaired performance. ”

Using crash data for the state of Michigan, Waller and Fred C. Blow, research director at the U-M Alcohol Research Center, found that female drivers caused 15 percent (8,258) of alcohol-related crashes and 33 percent (158,963) of total crashes in Michigan in 1980.

Ten years later, women accounted for 17 percent (5,541) of crashes involving alcohol and 39 percent (234,661) of total crashes, the researchers say.

Although the absolute number of alcohol-related crashes caused by female drivers fell 33 percent from 1980 to 1990, the decrease was less than that for men, whose drinking- related crashes dropped 44 percent (from 47,297 to 26,591).

As a result, the researchers say, the proportion of women involved in drinking and driving crashes has increased,relative to those caused by men.

Further, total crashes—including those not related to alcohol—increased 48 percent from 1980 to 1990 for female drivers, compared with a 15 percent rise(from 317,195 to 363,467) in total crashes caused by men during this time,the researchers say.

According to Waller and Blow, the disproportionate increase in crashes involving women is due to marked changes in their lifestyles, with many achieving economic independence.

“Women have entered the labor force in record numbers and the age of marriage has increased, so that many more are living independently,” they say. ” These changes have been accompanied by increasing rates of driver licensure and vehicle ownership, reflecting changes in driving behavior and increased driving exposure. ”

The study found that while, on the whole, women have responded favorably to efforts to reduce alcohol-related driving, women in their 30s and those over 65 have had greater rates of increases in drinking-related crashes than in total crashes.

Overall, the researchers say that alcohol affects women differently than men. ” Women appear to be more vulnerable to physiological damage from prolonged alcohol use,” they say. “They may also be more vulnerable to impairment of performance from low doses of alcohol. ”

Waller and Blow, whose study is published in the current.Recent Developments in Alcoholism, call for more gender-specific research, which is critical to understanding the role of alcohol in driving behavior.