Long combination vehicle operational field test
Authors: C. B. Winkler
The objective of this operational field test was to evaluate the stability enhancing characteristics, practicality/reliability, maintenance costs, and fleet personnel reactions to antilock braking systems (ABS) and double-drawbar dollies [C-dollies on long combination vehicles (LCVs)]. To do this, a fleet of double- and triple-trailer LCVs in actual commercial service was equipped with ABS and with double-tow-bar dollies and their performance monitored for a period of about one and one-half years. In that time, the test fleet accumulated approximately 1.4 million miles on trips within the study, and the individual units of the test fleet accumulated over 10.5 million unit-miles. Monitoring techniques included the tracking of all maintenance work done on the vehicles in the study, measurement of the physical behavior of the vehicles on the road by means of on-board instrumentation systems, and interviews with drivers, mechanics, and fleet managers. This report provides a detailed description of the test methods and results in the following sections: Background; Limitations of the Field Study; An Introduction to Terminology; An Overview of the Test Program (the participating fleets, vehicles, ABS equipment, special vehicle wiring, C-dollies and hitches, electronic data systems, duration of the study and mileage accumulations); The Performance of Antilock Braking Systems on Long Combination Vehicles; Maintenance and Operating Costs of ABS on LCVs; The Performance of C-Dollies in the Operations of LCVs; Maintenance and Operating Costs of C-Dollies on LCVs; and The Opinions of Fleet Personnel on ABS and C-Dollies in LCV Operations.