NHTSA slightly relaxes stopping distance mandate

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Updated Jul 27, 2011

The National Highway Traffic Safety Administration on Tuesday, July 26, announced that it is slightly relaxing its new stopping distance requirements for new truck tractors at lower initial speeds in response to petitions for reconsideration of the agency’s 2009 final rule.

NHTSA’s final rule amended the federal motor vehicle safety standard for air brake systems by requiring improvements in stopping distance performance on new truck tractors. This rule reduced the maximum allowable stopping distance at 60 mph from 355 feet to 250 feet for the vast majority of loaded heavy truck tractors. For a small minority of loaded very heavy tractors, the maximum allowable stopping distance was reduced from 355 feet to 310 feet.

NHTSA said that based on testing results and the agency’s concern that the current requirements of its final rule might not be practicable, the stopping distance requirement for typical loaded tractors tested from an initial speed of 20 mph is being relaxed slightly by increasing the distance from 30 feet to 32 feet, and for unloaded tractors tested from an initial speed of 20 mph from 28 feet to 30 feet.

The final rule is effective Aug. 1. For more information, go to www.regulations.gov; the docket number is NHTSA-2009-0083-0001.