The results of over 600 braking tests carried out on large mining trucks are presented in this paper. The tests were made over the past five years at mine sites in British Columbia on dump trucks having load capacities ranging from 35-200 tons. All tests were made with the vehicles fully loaded operating on downhill grades varying from 6-10%. Stopping distances were measured from the point of application of the service brakes from various initial speeds. The results are adequate, in some cases, to permit extrapolation of the observed values to indicate a likely “runaway” speed of the truck in the event of failure of the regenerative or other auxiliary retarding system.