High gas prices could turn out to be a lifesaver for some drivers. The authors of a new study say gas prices are causing driving declines that could result in a third fewer auto deaths annually, with the most dramatic drop likely to be among teen drivers.

Professors Michael Morrisey of the University of Alabama at Birmingham and David Grabowski of Harvard Medical School said they found that for every 10 percent increase in gas prices there was a 2.3 percent decline in auto deaths. For drivers ages 15 to 17, the decline was 6 percent, and for ages 18 to 21, it was 3.2 percent.

Their study looked at fatalities from 1985 to 2006, when gas prices reached about $2.50 a gallon. With gas now averaging more than $4 a gallon, Morrisey said he expects to see much greater drop — about 1,000 deaths a month.

With annual auto deaths typically ranging from about 38,000 to 40,000 a year, a drop of 12,000 deaths would cut the total by nearly a third, Morrisey said in an interview with The Associated Press.

"I think there is some silver lining here in higher gas prices in that we will see a public health gain," Grabowski said. But he cautioned that their estimate of a decline of 1,000 deaths a month could be offset somewhat by the shift under way to smaller, lighter, more fuel-efficient cars and the increase in motorcycle and scooter driving.

Morrisey said the study also found the "same kind of symmetry" between gas prices and auto deaths when prices go down.
"When that happens we drive more, we drive bigger cars, we drive faster and fatalities are higher," he said.

Morrisey and Grabowski found a nearly identical relationship between gas prices and auto deaths in an earlier study that covered 1983 to 2000. The studies used auto deaths tabulated by the National Highway Traffic Safety Administration, which hasn’t yet released figures for 2007.

Clarence Ditlow, executive director of the nonprofit Center for Auto Safety, said it makes sense that auto deaths would decline as driving decreases in response to rising gas prices.

"There are a whole bunch of factors that are influenced by higher gasoline prices — teenagers don’t have as much money, so you have the most risky drivers driving less; people are switching out of the bigger, older more dangerous vehicles, and people also know if they drive slower they’re going to save gasoline," Ditlow said. "So, from a societal viewpoint, higher gasoline prices have a great number of benefits, and one of the most important benefits is fewer traffic fatalities."

But Ditlow said he would be "delighted and amazed" to see deaths drop by a third. He said the declines in driving, while record-setting, still aren’t great enough to suggest such a dramatic drop is likely.

The Department of Transportation said last month that Americans drove 1.4 billion fewer highway miles in April, the sixth month in a row that driving was down and a historic turnaround after decades of annual increases in driving.

"We’re out there on a limb a little bit," Morrisey acknowledged, "but given that we get such consistent stories across the two time periods (in both studies) with somewhat different methodology, they seem to be pretty robust estimates."

Morrisey and Grabowski presented their findings to a meeting of the American Society of Health Economists in Raleigh-Durham, N.C., last month. The study was funded by the Robert Wood Johnson Foundation.