Rising to the defense of the heavy truck antilock brake requirement, the National Highway Traffic Safety Administration last week rejected a petition to drop the standard or give drivers the option not to use it.


The requirement, formally known as Federal Motor Vehicle Safety Standard No. 121, was implemented in 1997 as a way to improve the truck's stopping ability and directional stability during heavy braking. The antilock technology has since become the foundation of succeeding generations of onboard safety systems, such as electronic stability control and roll stability control.

The agency was responding to an October 2010 petition by William B. Trescott, Bay City, Texas. Trescott asked for a rulemaking to either drop the ABS requirement, amend it to allow automatic deactivation when the truck goes faster than 55 mph, or require an on-off switch for the driver.

Trescott contended that NHTSA's research shows that antilock systems lead to more fatal crash involvements and promotes incompetent driving.

He cited NHTSA's July 2010 statistical analysis of truck crash data that indicated mixed effectiveness of the standard. He said, for instance, that the research showed that ABS leads to only a 3% reduction in all crash types, and it increased overall fatalities by 1%.

ABS is effective in preventing jackknife crashes, but an unintended side effect is to allow incompetent drivers to stay in the business, he said in his petition. Before ABS, drivers who had a jackknife would have been fired; now they stay behind the wheel and get into other types of crashes, he reasoned.

The agency in its response challenged Trescott's analysis of the statistics, saying that the data in aggregate show a trend of fewer fatal crashes with ABS, even though subgroups of data do show increases in rear-end crashes by ABS tractors.

The agency said it cannot explain the rear-end crashes, but noted that the data are not detailed or conclusive enough to prove that ABS contributes to them.

The agency also said, "We do not believe that ABS somehow allows incompetent drivers to drive trucks."

Trescott in a telephone interview said the agency's response angers him. "I don't think they addressed the question," he said. "I asked for a study on whether an on-off switch would improve safety."

He did agree, however, with the agency's summary of his petition, which said he asked that the ABS requirement be dropped or amended to give drivers an option not to use it.

Trescott said he does not have standing to sue the agency in response but wondered aloud if any industry groups might join in. He said he has been pursuing this petition on his own without support from any carriers or industry groups.