Site Calculates Risk Factors for Travelers
A middle-aged male pedestrian is four times as likely, on any given trip, to be killed by a car as is an elementary school student, according to a new interactive Web site that lets people compare travel risks.
Published January 20, 2007 by The New York Times
By Matthew L. Wald
WASHINGTON — A middle-aged male pedestrian is four times as likely, on any given trip, to be killed by a car as is an elementary school student, according to a new interactive Web site that lets people compare travel risks.
The site allows users to assess the dangers of driving, walking, and riding a motorcycle or a bicycle, by season, region and personal characteristics of the traveler. It links two federal databases, one of traffic fatalities and the other of travel habits, to put the number of deaths into context by comparing them with what statisticians call exposure, or the extent to which people are in situations where there is a chance of a crash.
The site was put together by researchers at Carnegie Mellon University, with support from the AAA Foundation for Traffic Safety. It is being presented at the Transportation Research Board’s annual meeting, which begins Sunday, and is going public then, at hope.hss.cmu.edu.
Risk, the researchers emphasize, is not the number of people who die, but the probability of death per mile traveled, or per trip or minute of travel.
Linking the databases produces results that vary considerably from common perception, the Web site’s creators said. For example, the risk of death for an 18-year-old male driver is about the same as that for an 80-year-old female driver, but both are safer than the operator of a motorcycle. And counterintuitively, risk is higher in the mountains in summer than in winter.
“What surprised me most is that there were lots of surprises,” said Paul S. Fischbeck, the director of the Center for the Study and Improvement of Regulation at Carnegie Mellon and a professor of engineering and public policy.
For instance, Dr. Fischbeck said, “I knew that 80-year-olds and 18-year-olds were at high risks, but to have them at the same level of risk, it’s a very stark contrast.”
He said the original idea behind the Web site was to educate consumers. “But when you find things that are counterintuitive that you cannot explain,” he said, “that’s not good for education.” He said he planned to assign his students to try to find explanations.
The Web site allows a variety of comparisons. For example, the risk of death for vehicle occupants who are 16 to 20 years old, on weekdays, is 13.86 per 100 million trips between 8 a.m. and noon. But between 8 p.m. and midnight it is 30.51 per 100 million trips, more than twice as high.