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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Parts and Accessories Necessary for Safe Operation: Surge Brake Requirements

Notice of proposed rulemaking (NPRM); request for comments.

In response to a petition for rulemaking from the Surge Brake Coalition, the Federal Motor Carrier Safety Administration proposes to amend the Federal Motor Carrier Safety Regulations (FMCSRs) to allow the use of automatic hydraulic inertia brake systems (surge brakes) on trailers operated in interstate commerce. A surge brake is a self- contained permanently closed hydraulic brake system activated in response to the braking action of the tow vehicle. The amount of trailer braking effort developed is proportional to the total trailer weight and deceleration rate of the tow vehicle. Currently, surge brakes are not considered by FMCSA to comply with the FMCSRs specifying that all brakes with which a motor vehicle is equipped must at all times be capable of operating, and that a single application valve must, when applied, operate all the service brakes on the motor vehicle or combination of motor vehicles. The intent of this rulemaking is to adopt performance-based brake system requirements to allow the use of surge brakes on certain combinations of commercial motor vehicles based upon engineering test data submitted by the Surge Brake Coalition.

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