New speed limit does not increase fatality rate

WEST LAFAYETTE – The decision to raise the speed limit on Indiana’s interstate highways to 70 mph three years ago did not lead to more deaths or severe injuries from crashes, a Purdue University study found.\nState legislators heard worries that allowing speed limits on rural portions of interstates to rise from 65 mph would cause greater danger for motorists before the move was approved in 2005.\nFatalities on those highways, however, did not increase because drivers were already going faster than the posted speed limit and the differences in drivers’ speeds were lowered, said Fred Mannering, a civil engineering professor at Purdue who was the study’s co-author.\n“Most drivers are at 70 or 75,” he said. “When you have a driver at 55 and another at 80, you could see more accidents.”\nThe Purdue researchers used a series of mathematical equations to tally accident probabilities based on motor vehicle accident data from 2004 and 2006, the years before and after the speed limit increased.\nThe model took into account weather, type of vehicle and other variables.\nThe study found higher accident rates for some non-interstate highways where speeds were increased.\n“Interstate highways are designed for 70 miles-per-hour speeds,” Mannering said. “The interstate has the capacity to withstand those speeds.”\nIndiana State Police who patrol Interstate 65 in the Lafayette area have not seen an increase in fatalities since the speed limit was increased.\n“We are giving more tickets because we have increased the number of troopers at the post,” said state police Sgt. Kim Riley of the Lafayette post.\nSome regular drivers of I-65 also agreed with the study.\n“The amount of traffic, more cars on the road, leads to more accidents than the speed alone,” said Kevin Deboy, the owner of Deboy Trucking in Rossville.\nBob Combs, who has been commuting an hour from the Clinton County town of Mulberry to Indianapolis for 25 years, said he agreed with the decision to raise the speed limit.\n“If you run the interstate a lot, you’ll see people tend to be more alert and pay more attention when they are driving at these speeds,” Combs said. “Changing the speed was absolutely a good move.”