Weight Restrictions on Lodge Creek Bridge
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Motorists driving through or into Chinook have likely noticed the new weight limit sign at Lodge Creek. This sign is among several that the Montana Department of Transportation (MDT) has erected as part of new load posting procedures on public bridges across the state as mandated by the Federal Highway Administration (FHWA). Already subject to hundreds of regulations that apply to freight carriers and transport companies, many truck drivers expressed alarm at the sign.
A loaded semi-truck (tractor-trailer) will typically weigh 80,000 pounds, which is well over the posted limit of 30 ton. Therefore, such a limitation would virtually close this section of Highway 2 in Blaine County to truck traffic.
Upon consulting the MDT publication "Bridge Load Posting Program," a person would discover that the sign at Lodge Creek does not apply to ALL trucks. Therefore, area grain and livestock producers need not worry about receiving a citation for exceeding the weight limit as long as they are pulling a grain or cattle trailer that can be separated from a power unit-often referred to as a tractor. Passable configurations include operating a two-unit or even a three-unit vehicle.
Because the Lodge Creek sign features a silhouette of a single-unit vehicle, the thirty ton limit applies to any vehicle with a trailer permanently attached to its tractor. Single-unit vehicles include box trucks, moving trucks, dump and concrete trucks, or buses. Because the sign reads: Weight Limit 5-7 Axles 30T, the maximum GVW is based on the vehicle's number of axles. This is not a single limit sign.
In the last decade, manufacturers have developed specialized hauling vehicles (SHVs) that are capable of legally carrying heavy, concentrated loads. These vehicles have been found to overstress bridges more than standard vehicle types of the past. To account for their increasing presence and to ensure safe operation, the FHWA has developed guidelines that standardize legal loads for SHVs that all States are required to use in bridge analysis and posting. Based on these new vehicles guidelines and on other safety-based bridge engineering evaluations adopted by the FHWA, the Lodge Creek sign was deemed necessary.
According to the MDT, not all bridges were designed to carry today's standard legal loads, and some bridges have deteriorated over time. Bridge weight restriction signs are posted to keep motorists and their vehicles safe. They are also posted to prevent certain loads from crossing and overstressing the bridge, which could lead to both visible and hidden damage, and to eventual closure or failure of the bridge. To prevent any overload and damage, to maintain the integrity of a bridge, and to safeguard bridge longevity, the MDT asks for motorists' responsible cooperation.
The MDT stressed that weight restrictions do not mean that a bridge is unsafe, as long as vehicles meet the posted limitations. Rather, bridge load posting will help MDT safeguard vital transportation infrastructure.
Anyone wishing to learn more about the Montana Bridge Load Posting Program or about load postings signs and how to interpret them is encouraged to visit the MDT website.
