National Highway Traffic Safety Administration Amends Stopping Distance Requirement

(The following information is based on the NHTSA’s ruling located in the Federal Register and available at!documentDetail;D=NHTSA-2009-0175-0006)


Earlier this week, the National Highway Traffic Safety Administration (NHTSA) published a new requirement for the stopping distance of truck tractors, in response to an earlier ruling.

In July of 2009, the agency issued a ruling requiring an improved stopping distance for heavy trucks, reducing the distance of trucks traveling at 60 mph from 355 feet to 250 feet, allowing a minority of very heavy tractors a stopping distance of 310 feet.

The ruling, however, sparked the response of eight petitions based on four main issues.  One of them, having to do with the stopping distance requirements, was challenged by the TMA, HDBMC, and Bendix, who believed that “speeds lower than 60 mph have not been validated through actual vehicle test data” and that “the brake timing may be too fast for some vehicle configurations.”

Therefore, the NHTSA was asked to remove the new requirements until tests could be conducted and results obtained.  The NHTSA accepted and “required compliance with the improved stopping distance requirements for tractors with four or more axles and a GVWR of 59,600 pounds or less by August 1, 2013.”

NHTSA conducted tests analyzing the stopping distance of a tractor trailer traveling at 60 mph, 55 mph, 50 mph, and so on down to 20 mph, repeating the test with a lightly loaded vehicle weight (excluding the trailer).

The results showed that when the tractor was loaded to GVWR and traveling at 20 mph, it obtained a stopping distance of 31.2 feet…1.2 feet more than the required amount.

After gathering all of the results, the NHTSA decided that the requirements may not be practicable and increased the stopping distance for a loaded truck traveling at 20 mph from 30 to 32 feet and for an empty tractor traveling at the same speed from 28 to 30 feet.

The NHTSA’s new ruling will become effective on Monday, August 1st with petitions being accepted up until September 12th.

How is Road Scholar Transport improving their stopping distance?  We have equipped trucksall of our new tractors with disc brakes for safety as well as purchased trucks with the Bendix Wingman ACB System which works to maintain a set distance of 8/10ths of a mile marker behind a forward vehicle, preventing accidents by automatically reducing the throttle, using the engine retarder, or applying the brakes.

Wouldn’t you rather your freight onboard trucks equipped with anti-crash technology?  If so, then visit to schedule your LTL or truckload freight.

What do you think of the NHTSA’s stopping distance requirements?

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