Drivers can assume that each 5 MPH they drive above 60 MPH, according to the Governor's Highway Safety Association (GHSA), is like paying an additional 20 cents a gallon for gas. Additionally, aggressive highway behavior such as speeding, rapid acceleration and braking can lower gas mileage by a whopping 33% at highway speeds and 5% around town.
According to a GHSA survey of state highway safety agencies, Wisconsin, for example, has reported a noticeable level of slower vehicle speeds stemming from recent price hikes. Officials there say traffic volume is down slightly, but speeds are also down, which may account for fewer and less serious traffic crashes across the whole state.
Commercial vehicles are slowing slightly, State troopers report, with many traveling at or below the speed limit. That's not surprising because independent long-haul truckers are known for ruthlessly watching their costs, and truck fleet managers do the same. A handful of other state officials noted the reduced speed of commercial vehicles, likely resulting from more trucking companies setting policies that require their drivers to stay below a set speed, such as 67 mph. Some companies' trucks are wired so that fleet managers know if the drivers have topped the speed.
In addition to helping fight the cost of record-high gas prices, slowing down also increases the likelihood of surviving a crash. "I try to remember to slow down," says Eduardo Rodriguez, a resident of upper Manhattan in New York City. "But today, it's always hurry, hurry, hurry everywhere you go. Everybody's gotta be there yesterday, and if you do the legal speed limit of 55 or 60 MPH, people tailgate you or beep their horn. You can't obey the law even if you want to without getting grief on the highway."
In a high-speed crash, according to the Insurance Institute for Highway Safety, a passenger vehicle is subjected to forces so severe that the vehicle structure cannot withstand the impact of the crash and maintain survival space in the occupant compartment.
Further evidence comes from a recent study that showed even a small reduction in speed can have a big impact on lives saved. In the report, published in the Transportation Research Record, author Rune Elvik found that a 1 percent decrease in travel speed reduces injury crashes by about 2 percent, serious injury crashes by about 3 percent and fatal crashes by about 4 percent. These reductions are critically needed, traffic safety experts say, as speeding remains a serious highway safety problem. Nearly 13,500 people died in speed-related crashes in 2006.
Nationally, GHSA members report that they are not seeing much noticeable decrease in travel speeds by passenger vehicles. "However, given the extremely high gas prices and life-saving benefits of slowing down, we urge the public to ease off the accelerator," says GHSA Chairman Christopher J. Murphy says.