In the early days of this site I once discussed axle positions and the often confusing bridge formulas that vary from state to state. Depending on what state you run your truck you can get away with different axles positions and setups that might work for one location but not the other. Similar to the bridge formula, the increase in APU’s (Auxiliary Power Units) has raised its own unique set of state by state laws.
For the inquiring minds an APU allows a trucker to have power for such things as heat, air conditioning and lights without the need to run the truck’s engine. Typically an APU is diesel powered generator located between the cab and rear axles. With many localities across the country having passed laws prohibiting trucks from idling for any reason for longer than a few minutes an APU became something of necessity over a luxury. While viewed as better for the environment an APU can add anywhere from five to seven hundred pounds to a truck’s gross total weight. It might not sound like much when we’re talking about 60,000 lb cargos but for operators that run close to the limit the pounds add up.
Realizing that auxiliary power units were eating into cargo capacity, exemptions were allowed to deduct specified weights from a truck’s total weight. Much like the axle weight positions noted above each state has their own specific criteria. For drivers that routinely cross state lines knowing exactly how much APU forgiveness they are allocated can be confusing and possibly lead to massive overweight fines if not figured correctly.
With that in mind the good people at TruckYourTruck.com have put together a handy list of what to expect with your journies. Check it out and let me know if you find it helpful.