an improved approach to the economically ideal bed size making each haul cycle more profitable because spilled rocks of certain sizes are typical causes for damage to truck tires a reduction of spillage provides both safety and economic benefits the haulage process another possible technique shown in fig3 that will reduce the possibility of spillage is to deposit the payload 114 on the bed 13 at a position 118 that is closer to the front end 16 of the bed 13 than the position 18 illustrated in fig1 by moving the load position 118 forward the risk of spillage off the rear end 15 of the bed 13 while traversing up a steep grade 111 may be reduced a fixed loading angle may not fit all types of payloads so it may be preferable to introduce an adjustable loading angle u03b2 such an adjustable angle u03b2 would be used for variations in the grade angle u03b8 of the haulage paths from one location to another for variations in the angle of repose u03b3 of various materials and by limiting the loading capabilities of the bed 13 before the granular material 12 begins to fall off the rear end 15 of the bed 13 the hoist mechanism 21 may be controlled and activated by a controller 22 which may be a separate or dedicated controller or part of the engine control module ecm of the truck 10 the controller 22 may include a memory 23 for the storage of the angle of repose u03b3 of the granular material 12 being transported or various angles of repose u03b3 for various granular materials that the truck 10 is expected to transport the tilt.