Abstract
This report described trials carried out with 250 articulated vehicles, some with load sensing valves fitted to the rear wheels of the tractor units and some without, in order to see what effect the valves had on accident rates. During a period of three years, records of accidents involving all these vehicles were examined and analyzed in detail. The evidence showed that load sensing valves reduced (but did not eliminate) jack-knifing accidents but the overall accident results were disappointing.