Demonstration of the Safety Benefits of Front Brakes on Heavy Trucks

摘要

The report describes a test program that was conducted by the U.S. Department of Transportation in September 1986 to demonstrate the safety benefits of brakes on the front (steering) axles of heavy duty vehicles. Twelve volunteer over-the-road truck drivers were asked to drive vehicles in various braking maneuvers with four different front brake configurations: full front brakes, limited front brakes, no front brakes and one front brake, only. Test vehicles included two bobtail tractors, two empty tractor semi-trailers and one fully loaded (80,000 lb) tractor semi-trailer. Test maneuvers included straight line braking, braking in a turn and braking in a lane change. Most tests were run on wet, slippery pavement although some stops were also performed on dry asphalt. Results of the tests indicated that braking performance and control of the vehicles were optimized when full front brakes were utilized.