The Montana Department of Transportation has asked us to remind everybody about new restrictions for weight as they continue to work on public bridges across the state. Keep an eye out for new signs in places that you're used to hauling loads, there may be new weight limits in place.The postings are part of recently updated federal requirements for bridge load rating and posting.

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 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. Pretty simple stuff, the MDT just wants you to be on the lookout for new signs.

“Many older bridges were never designed to carry vehicle types that have become common in present-day use, and some bridges have deteriorated over time,” MDT Bridge Engineer Stephanie Brandenberger said. “Bridge weight restriction signs are posted to keep motorists safe and to ensure that the bridge remains functional. We need to prevent heavy loads from crossing and over-stressing the bridge, which can lead to both visible and hidden damage.”

The MDT is currently updating load ratings for 4,500 public bridges across the state, including approximately 2,500 owned and maintained by MDT. This won't be a quick job, it will be going on for about 4 years. They wanted to emphasized that weight restrictions do not mean a bridge is unsafe, as long as vehicles meet posted limitations.