Efforts in the 1970's to require that United States heavy vehicles be equipped with antilock braking systems (ABS) were unsuccesful. This is partly due to the truck user concerns about the in-service operational reliability and serviceability of the systems. As a necessary pre-step to reconsidering a requirement for ABS, the National Highway Traffic Safety Administration (NHTSA) began, in 1988, a large in-service field evaluation of current-generation ABS systems. The aim was to determine if they would function reliably in U.S. trucking operations. Reliability and serviceability has been tracked on 200 ABS-equipped truck tractors, operated by seventeen fleets in six U.S. cities for a two-year period beginning in late 1988/early 1989. Beginning in late 1990, 50 ABS-equipped trailers were added to the program, for a two-year period. Maintenance records and specifically designed on-board monitor/recorder systems have been used to monitor system operation. Data from the recorders indicates that: (1) the ABSs function is used more frequently than might have been expected; and (2) the frequency of operation increases, as would be expected, during the winter months. Driver acceptance of the systems has been favourable. Maintenance information collected to date indicate that ABS can be succesfully installed and maintained on U.S. heavy vehicles.
Samenvatting