WASHINGTON, D.C. – The U.S. National Highway Traffic Safety Administration’s plan to shorten the allowable stopping distances for tractor-trailers continues to be bogged down in the regulatory process. The latest delay in unveiling the new stopping distances – expected to be as much as 30 per cent shorter than those in place today – is being linked to a “cost-benefit” analysis of the new standards. They were originally slated to be introduced in an Advanced Notice of Proposed Rulemaking (ANPRM) in 2003.

But the addition of the cost-benefit analysis will pave the way for the rules to be unveiled as a Notice of Proposed Rulemaking, which could become a regulation more quickly than an ANPRM, explained Jim Britell of NHTSA’s Office of Vehicle Safety Research.

While NHTSA can set requirements for stopping distances, it will be up to the trucking industry to develop a way of doing it.

Tractor-trailers with a Gross Vehicle Weight Rating (GVWR) of 52,000 lb. currently need to stop from speeds of 60 mph within a distance of 355 feet – a requirement easily met by either size of brakes. But problems emerge if the allowable distances are shortened to 248 feet, since trucks equipped with 15×4 brakes on steer axles will only come to a rest within 244 feet. A 16.5×5 brake on a steer axle will bring the truck to a stop within 206 feet.

Sources close to the discussions, however, admit certain configurations, including some cement trucks, may find it particularly difficult to meet the new standards.

As for potential changes to stopping distances in Canada, Transport Canada tends to mimic manufacturing requirements set in the U.S., but has yet to introduce any similar legislation.