Bridge Formula Definition
The bridge formula is a mathematical expression used to find the gross weight of a vehicle. The calculations are generally based on the axle number as well as their spacing. The bride formula's design was initially intended to reduce any typical commercial vehicle's weight-to-length ratio crossing a bridge.
The appropriate weight distribution for your cargo and vehicle can be achieved in one of two ways. You can increase the length between the existing axles to attain compliance or spread the shipment's weight over several additional axles.
How do I Achieve the Correct Bridge Weight?
The bridge formula takes into account three variables:
Your vehicle's gross weight (GWV) is the total weight of the cargo, trailer, and truck. The Federal Gross Vehicle Weight means that interstate travel is restricted to 80 000 lbs. There are, however, cases when the bridge formula might dictate otherwise.
In the event when your axles are spaced more than 40' apart, the weight limit of a single axle is 20 000 lbs. If the shafts are less than 97' apart, the interstate weight limit is set at 34 000 lbs. Some interstates may have lower or higher weight limits. This disparity comes as a result of some weight limits being "grandfathered." This means that the original weight restrictions have been maintained despite changes to the formula.