Idle Reduction and Natural Gas Vehicle (NGV) Weight Exemption

Any motor vehicle equipped with an auxiliary power unit (APU) or other idle reduction technology may exceed the gross, axle, tandem, or bridge formula weight limits by up to 400 pounds (lbs.). To be eligible for the weight exemption, the vehicle operator must be able to provide written proof or certification of the weight of the APU and demonstrate or certify that the idle reduction technology is fully functional at all times. A vehicle primarily powered by natural gas may exceed the state’s gross vehicle weight limits by a weight equal to the difference between the weight of the vehicle with the natural gas tank and fueling system and the weight of a comparable vehicle with a diesel tank and fueling system. The NGV maximum gross weight may not exceed 82,000 lbs.

(Reference Code of Alabama 32-9-20)