Safety Benefits, Fewer Crashes Confirmed in Federal Study of Truck Speed Limiters

Devices that electronically limit the top speed of trucks have “profound” safety benefits and significantly reduce speeding-related accidents, a federally sponsored study released last week found.

The report used data from 20 fleets — both with and without the devices — and is the first speed-limiter study to analyze actual crash data, its authors wrote.

“Results from multiple analyses indicated a profound safety benefit for trucks equipped with an active [speed limiter],” the study said. It was conducted by a group that included the Virginia Tech Transportation Institute and the American Transportation Research Institute.

The study supports American Trucking Associations’ position that all trucks should have speed limiters set at 65 mph, the group said.

“This study confirms what ATA has been saying for years — speed kills, and one of the most effective ways to prevent hundreds, if not thousands, of crashes on our highways is to slow all vehicles down, including large trucks,” ATA President Bill Graves said in a statement.

ATA asked federal regulators in 2006 to limit trucks to 68 mph but later changed its position to 65 mph, federation spokesman Sean McNally said.

The National Highway Transportation Safety Administration, which has the power to mandate the devices on new vehicles, agreed in 2011 to consider a requirement after ATA petitioned both NHTSA and the Federal Motor Carrier Safety Administration (1-10-11, p. 1).

“The findings support the preponderance of evidence that if you slow trucks down, you’re going to get a significant safety benefit,” David Osiecki, senior vice president of regulatory affairs at ATA, told Transport Topics. “ATA’s been saying that for years; this adds weight to our argument.”

The study found a “strong, statistically significant” decrease in speed limiter-related crashes — those that speed limiters were meant to prevent — in trucks using the devices when compared with trucks that did not use them. It did not find any statistically significant difference in overall crash rate.

Speed limiters used in the study were set between 62 mph and 70 mph. The fleets included 138,000 trucks that were involved in 15,000 traffic incidents during the three-year study period.

“It’s important to acknowledge the size of this study, the fact that it was done in the field,” Osiecki said. “They looked at actual crash data for trucks using speed limiters and trucks not having an active speed limiter. Multiple statistical tests were run, and those analyses found that the safety benefits are there.”

Every truck manufactured from 1992 onward has a speed limiter installed, Osiecki said. That means the cost of complying with a mandate would be very low, because the device needs only to be activated.

Osiecki urged FMCSA to require that all existing trucks have active speed limiters. An FMCSA spokeswoman said the agency has not proposed a rule for existing trucks.

The Department of Transportation’s most recent monthly report on rulemakings said NHTSA expects to issue a rule proposal in August.

The Owner-Operator Independent Drivers Association took issue with the report, calling it a reversal of conclusions outlined in a 2010 draft of the report.

“It’s not a new study at all,” said spokeswoman Norita Taylor. “They simply threw out specific pieces of information that did not fit the biased agenda to impose speed limiters.”

OOIDA opposes speed limiter requirements, saying that it would cause unsafe speed differentials between trucks and other vehicles on highways (1-10-11, p. 1).

“All credible highway research shows that highways are safest when all vehicles travel at the same speed and that different speeds for cars and trucks actually increase the likelihood of accidents,” OOIDA Executive Vice President Todd Spencer previously told TT.

However, by demonstrating safety benefits of using speed limiters, the study showed that the benefits of the devices outweigh any problems from speed differentials, Osiecki said.

“This report does find that the safety benefits of the use of speed limiters overcome the potential negatives of speed differentials between cars and trucks,” he said.

OOIDA also has warned that mandating speed limiters could slow down the movement of goods (10-3, p. 4). The report released last week did not examine that possibility.