Safety is No Accident. Visit the National Safety Commission - America's Safety Headquarters for driver safety information, auto recalls and teen safe driver tips.
Tuesday, November 20, 2007
Study Shows Deaths Caused By Time Shift
Two scientists calculate that pedestrians walking during the evening rush hour are nearly three times more likely to be struck and killed by cars now that the clocks have recently been turned back. According to researchers, ending daylight saving time means roughly 37 more U.S. pedestrian deaths around 6 p.m. in November compared to October.
Although preliminary, their study of risk to pedestrians validates previous findings of more deaths after clocks are set back in fall.
According to professors Paul Fischbeck and David Gerard, both of Carnegie Mellon University in Pittsburgh, it's not the darkness itself that's the killer, but the adjustment to earlier nighttime.
Fischbeck regularly walks with his 4-year-old twins around 6 p.m. He's worried enough that he'll be more cautious.
"A three times increase in the risk is really dramatic, and because of that we're carrying a flashlight," he said.
After conducting a preliminary study of seven years of federal traffic fatalities, Fischbeck and Gerard calculated risk per mile walked for pedestrians. They discovered that per-mile risk spikes 186 percent from October to November, but then drops 21 percent in December.
The drop-off by December points out that the risk is caused by the trouble both drivers and pedestrians have in adjusting to the darkness suddenly coming an hour earlier.
In the morning, the reverse happens when clocks are set back and daylight comes earlier. Pedestrian risk plummets, but there are fewer walkers then, too. The researchers found that the 13 lives saved at 6 a.m. don't offset the 37 lost at 6 p.m.
The scientists said the risk for pedestrian deaths at 6 p.m. is by far the highest in November. The danger falls off each month through May.
In earlier studies, The Insurance Institute for Highway Safety of Arlington, Va. found the switch from daylight saving time to standard time boosted pedestrian deaths. The institute calculated that going to a year-round daylight saving time would save about 200 deaths a year, said spokesman Russ Rader.
"Benjamin Franklin conceived of daylight savings time as a way of saving candles," Rader said. "Today we know it saves lives."
Fischbeck and Gerard found that the risk at 6 p.m. in November, after daylight saving time ends, is 11 times higher than the risk for the same hour in April, when daylight saving commences.
The Carnegie Mellon researchers used federal traffic fatality data that they've incorporated into a searchable database for different risk factors. Their findings were not peer-reviewed and are not being published in a scientific journal.
But it is supported by other peer-reviewed studies that examined raw fatalities.
In 2001, John M. Sullivan at the University of Michigan studied national traffic statistics from 1987 to 1997 and discovered there were 65 crashes killing pedestrians in the week before the clocks fell back and 227 in the following week.
Fischbeck and Gerard discovered the growth in fatality risk after the end of daylight saving time pertains only to pedestrians. No such spike was evidenced for drivers or passengers in cars.
They said that once everyone "springs forward" to daylight saving time in April, there is a 78 percent drop in risk at 6 p.m.
But overall for the evening rush hour, turning the clock back is deadly. In 7 years, 250 more deaths occurred in the fall and there were 139 fewer deaths in the spring.
"This clearly shows that both drivers and pedestrians should think about this daylight savings adjustment," Gerard said. "There are lives at stake."
To further assist parents, Lowest Price Traffic School is also involved in educating new drivers and has designed a Parent-Teen Driving Contract, which highlights the key areas for discussion, and offers an agreement to ensure that their teen is driving safely.