Montana Department of Transportation


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Montana Bridge Load Posting Program

Montana Bridge Load Posting Program logo


The Montana Department of Transportation (MDT) has begun placing new load posting signs at some of its bridges around the state.

Bridge load posting is a matter of public safety and will help MDT safeguard vital transportation infrastructure. Based on recent safety-based bridge engineering evaluations, new vehicle types, and updated mandates from the Federal Highway Administration (FHWA), the new load postings will indicate the maximum amount of weight that can legally cross a bridge for different vehicle types.

image of a Posted bridge over Smith River (near White Sulphur Springs)
Posted bridge over Smith River (near White Sulphur Springs)

Bridge load posting means restricting weight on Montana's bridges

Bridge weight restrictions are required when the engineering analysis of a bridge, known as a load rating, indicates that it cannot carry standard, legal loads. Load ratings provide information about how much distributed weight can safely pass over a bridge. Load posting of bridges is required when a load rating indicates that a bridge cannot safely carry certain loads that would otherwise be legal in the state of Montana. Load posting signs show maximum weight limits for different vehicle types, depending on their axle configuration.

To learn about load postings signs and how to interpret them, see the Bridge Load Posting brochure.

Weight restrictions are required and important for Montana's bridges

Load posting of bridges is essential to the safety of the traveling public. Not all bridges were designed to carry today’s standard, legal loads, and some bridges have deteriorated over time. Load posting, or weight restriction signs are installed to keep motorists and their vehicles safe. They are also posted to prevent certain loads from crossing and over-stressing the bridge, which could lead to both visible and hidden damage, and eventual closure or failure of the bridge.

A posted bridge is safe to use, but the weight of certain vehicles must be limited accordingly. MDT needs your help to prevent overload and damage, maintain the integrity of the bridge, and safeguard bridge longevity.

MDT Bridge Management Program