APU weight allowances by state

By Land Line staff

It’s been more than 10 years that a big problem with auxiliary power units caused major headaches for truck drivers who installed the units – they simply weighed a lot. That added weight threw axle weight- limit compliance into question.

To address the question, an exemption, which was signed into law by President Bush in August 2005 as part of the Energy Policy Act of 2005, increases a vehicle’s maximum gross vehicle weight limit and axle weight limit by 400 pounds. This allows for the adding of a qualified idle-reduction technology, such as an APU.

Following that, there was even a rulemaking. The Federal Highway Administration solicited comments. The gist of the rulemaking “required” by demonstration and/or certification from the manufacturer that the idle-reduction technology “is functional at all times, does not exceed 400 pounds gross weight (including fuel), and that the unit cannot be used for any other purpose.”

But, after all that – a law and a proposed regulation – a memo written by FHWA’s Size and Weight Division in November 2005 said that the exemption won’t be treated as a federal mandate.

“We determined that (the exemption) does not pre-empt state regulations or compel the states to grant the increased weight tolerance,” the FHWA memo said. “Rather, (the exemption) simply increases the federal interstate maximum weight limits to compensate for the weight of the APUs installed.”

Environmental Protection Agency officials voiced their concern over an exemption that would not be honored nationwide.

“The non-pre-emptive nature of the 400-pound weight waiver creates a disincentive for trucking companies and owner-operators to purchase and use mobile idle-reduction technologies,” an internal EPA memo stated. “Truck owners have no way of knowing whether … a particular state may issue them a citation for their APU weight.”

Early on Land Line received reports from truckers that enforcement officials in several states would not acknowledge the higher limit. Some state officials simply were not explicitly acknowledging the exemption, but indicating that their weight tolerances would cover an additional 400 pounds.

Congress doubled down on giving truckers that extra latitude on truck weight for APUs and the like when it passed the short-term highway bill Moving Ahead for Progress in the 21st Century. In the bill, Congress upped the weight tolerance to 550 pounds.

It may have taken more than a decade, but the vast majority of the problem has finally been resolved.

Land Line State Legislative Editor Keith Goble has tracked bills in statehouses around the country and tracked the progress toward getting actual exemptions written into state law. He maintains a handy chart online at OOIDA.com that is updated when legislation is on the move or signed into law. You can see the state-by-state breakdown here as of July 18.

To date, only six states/regions remain holdouts on granting or honoring some sort of exemption. Those are California, the District of Columbia, Hawaii, Kentucky, North Carolina and Rhode Island.