Reduced Load Restrictions

Under some circumstances, such as structural weakness, it is necessary to limit the gross weight of vehicles on bridges temporarily. The overall vehicle weight impacts the bridge structure and the same maximum weight restriction applies to both single and combination vehicles. The maximum tonnes sign (single gross weight -Rb-63) is used to limit loads on constrained bridges.

This sign must be used on bridges where the same maximum gross weight applies to single and combination vehicles. A structural assessment of the bridge is required prior to passing a by-law authorizing the weight restrictions.

This sign is used to limit the weights of heavy vehicles on weak bridges. In some situations, vehicle configuration and the weight distribution of two different vehicle components across the bridge structure are critical to the safety of the bridge.

This sign must be used where structural engineers have set individual load restrictions requiring the maximum permitted gross vehicle weights for a single-vehicle unit (e.g. cube truck), a combination of two vehicles units (e.g. a tractor and trailer) and a combination of three vehicle units (e.g. a tractor and two trailers). The Rb-63A sign indicates the maximum weight for each vehicle combination.

It also must be used on bridges where the different maximum gross weight applies to single and combination vehicles. A structural assessment of the bridge is required prior to passing a by-law authorizing the weight restrictions.