What is an APU?

APU is short of Auxiliary Power Unit.  Some trucks have APU’s equipped to help reduce the tractors idle cost by offering a more fuel saving solution to idling the tractor. The APU is a self-contained generator that powers up the auxiliary equipment within the cab of the tractor.  Some APU’s are even capable of running the heat and AC within the tractor. The higher the cost of diesel the better return on investment an APU will provide.  Since APU’s only use a portion of the fuel that idling the tractor would the need for APU increase as the cost of diesel increases.

Auxiliary power units (repeatedly referred to as APUs) remove the need to run truck engines on idle while parked and are regularly used by truck drivers to monitor fuel use. One drawback of these units is that they normally weigh several hundred pounds, and could be a problem for drivers who carry close to highest weight limits. With the president’s latest expansion of the MAP-21 bill dealing with state-by-state APU regulations, this may be confusing to drivers who habitually cross state lines.

Below we’ve placed a helpful guide, created by fleet tracking systems company Track Your Truck, that notifies drivers just how much APU weight is exempt in each state.

APU Exemption Guide