The Findings presented in this paper are based upon the investigation and reconstruction of more than 250 commercial vehicle accidents. Practical methods yielding acceptable results in terms of speed determination and fade and temperature prediction in truck run-away accidents are presented. The importance of accurate and complete data collection with respect to accident scene, mechanical condition of the vehicle, and driver human factors are discussed.The effects of complete, partial and no-wheel lockup on accident reconstruction are discussed for straight and out-of-control motion of the vehicle, including Jack-knifing. The importance of front wheel brakes is considered.The engineering concepts used in the analysis of accidents involving brake fade are presented including factors such as Jake brake, brake adjustment, and heat checking of drums. Driver factors are also considered. Truck rollover mechanics as it applies to braking accidents is reviewed. The effects of brake system design on accident causation are briefly discussed.Accident causation due to brake system maintenance is analyzed. Utah roadside inspections reveal that as many as 41% of the tractor-semitrailers operating on our highways are shut down due to defective brake maintenance.