the front axle and 80 percent each to the rear tractor truck axle and semi trailer axle: Front axle load = 0.20(50,000) = 10,000 lb Rear tractor and semitrailer axle loads = 0.80(50,000) = 40,000 lb For lane loading, the uniform load is 0.016 times the weight of the tractor truck: Uniform lane load = 0.016(50,000) = 800 lb/ft