A Performance-Based Brake Test (PBBT) is any device which can quantitatively assess the braking performance of a vehicle. This is done through direct measurements of the brake forces at each wheel, axle or for the vehicle as a whole. Such devices include roller dynamometers, flat plate brake testers, breakaway torque brake testers and drawbar-type testers. Each of these devices can determine the brake forces without restriction to brake type (disk or drum) or energy supply (air, hydraulic or electric). In addition, PBBTs based on mechanical or electronic decelerometers can assess the overall vehicle braking capability through a stopping performance test in which deceleration and/or stopping distance is obtained, also independent of brake type or application method. Some PBBT types have been used worldwide for decades for both safety inspections and as part of regular Preventive Maintenance (PM) work in fleet shops.
A pbbt is an important part of truck safety.