Federal Bridge Formula establishes the maximum weight any set of axles may legally carry on the Interstate roadways. The FBF is a mathematical formula used to determine the appropriate weight of loads based on axle configuration (number of axles, axle spacing, weight distribution). The formula is as follows:
This formula can look intimidating, because of that, Oversize.io has developed a calculator to determine whether your load meets FBF guidelines. (See Also: State Axle Weight Regulations)