What’s a Bridge Formula?
In trucking, a bridge formula refers to a mathematical expression that helps arrive at the gross weight of a vehicle. The expression is derived from the axle number and their spacing. These axles include single axle weight and tandem axle weight alongside the gross vehicle weight. The bridge formula was intended to minimize the usual commercial vehicle weight-to-length ratio that crosses a bridge. Cargo weight can be appropriately distributed in either of two ways. The first one is done by spreading the weight of the shipment across some additional axles, and the second by maximizing the length between the fixed axles for compliance. A bridge formula also allows less weight for closely spaced axles.
Importance of a Bridge Formula
As per the federal weight regulations, bridge formula compliance is inspected by officials posted at the weigh stations. These officials lie in the environs of big cities or, at times, the state borders. The purpose of weighing is to ensure the truck's weight lies within the expected legal limits. The usual weight limit is up to 80,000lbs. However, it is important to note that tankers are an exception in bridge formula compliance. This is because the Federal government from the American Trucking Association requested so.