SAE J 690:1998-11-06

[In the report of the SAE Motor Truck Rating Committee on Ability Ratings published in the January 1940 issue of the SAE Journal, it was recommended that pounds per certified net brake horsepower delivered to the clutch or its equivalent be used as the index of the potential ability of a motor truck or combination. This report defined the term "certified net brake horsepower" in detail and recommended that certain data be provided to support the certification. The accompanying forms provide a method for the presentation of the data specified.]