The solution was to link allowable weights to the number and spacing of axles.ДЄxle spacing is as important as axle weight in designing bridges. As trucks grew heavier in the 1950s and 1960, something had to be done to protect bridges. Is the Formula Necessary?Д«ridges on the Interstate System highways are designed to support a wide variety of vehicles and their expected loads. Gross vehicle weight is limited to 80,000 pounds (23 U.S.C. In addition to Bridge Formula weight limits, Federal law states that single axles are limited to 20,000 pounds, and axles spaced more than 40 inches and not more than 96 inches apart (tandem axles) are limited to 34,000 pounds. N = the number of axles in the group under consideration. L = the distance in feet between the outer axles of any group of two or more consecutive axles.

W = the overall gross weight on any group of two or more consecutive axles to the nearest 500 pounds. This is accomplished either by spreading weight over additional axles or by increasing the distance between axles.Д¬ompliance with Bridge Formula weight limits is determined by using the following formula: What Is It?Д¬ongress enacted the Bridge Formula in 1975 to limit the weight-to-length ratio of a vehicle crossing a bridge. This pamphlet describes the Bridge Formula, why it was established, and how it is used. With a few exceptions noted in this pamphlet, the Bridge Formula establishes the maximum weight any set of axles on a motor vehicle may carry on the Interstate highway system. In the event of a dispute, the statute and regulation take precedence with respect to maximum allowable Federal Bridge Formula weights. This guidance paraphrases provisions of 23 U.S.C. Previous editions of this guidance pamphlet are superseded and no longer valid. The Federal Highway Administration (FHWA) revises its guidance pamphlet Federal Bridge Formula Weights (May 2015).

You may need the AdobeВ® ReaderВ® to view the PDFs on this page.Д¬ontact Information: Operations Feedback at Department of Transportation Home > Truck Size & Weight Bridge Formula Weights

Flatbed dual axle weight distribution