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, single axle, tandem axle, or bridge formula weight limits by up to 550 pounds (lbs.) to compensate for the weight of the technology. 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 or idle reduction technology, and demonstrate or certify that the technology is fully functional at all times.
Furthermore, NGVs may exceed the weight limits by an amount equal to the difference of the weight of the natural gas tank and fueling system and the weight of a comparable diesel tank and fueling system. The NGV must not exceed a maximum gross vehicle weight of 82,000 lbs. (Reference Iowa Code 321.463)