Wisconsin becomes 15th state to permit 550-pound APU exemption

December 8, 2017

Keith Goble


In an effort to encourage more truck drivers to stop idling, a new law in Wisconsin raises the allowable weight limit for trucks.

States were given the ability in 2005 to allow heavy-duty trucks to exceed the 80,000-pound maximum weight limit to encourage the use of idle-reduction equipment.

During the next decade many states adopted rules to increase the weight limits for trucks equipped with auxiliary power units up to an additional 400 pounds. Wisconsin is among the states that acted.

According to the U.S. Department of Energy, 17 states have laws that authorize the weight allowance for commercial vehicles. There are 14 states where the weight allowance is granted by enforcement policy rather than by state law.

In 2012, the federal transportation law included a provision to allow states to increase their APU weight exemption another 150 pounds to 550 pounds. The change was sought to accommodate newer technologies available for truckers that consume less fuel, but weigh more.

Thirteen states have enacted laws to authorize APU exemptions up to 550 pounds. Arkansas grants 550-pound exemptions via enforcement policy.

Wisconsin Gov. Scott Walker has signed into law a bill to boost the state’s weight exemption from 400 pounds to 550 pounds. SB198 took effect on Tuesday, Dec. 5.

States yet to permit a weight exemption for APU use are California, Hawaii, Kentucky, North Carolina and Rhode Island. The weight allowance doesn’t affect state highway funding eligibility.

A full list of state APU weight exemptions is available.