The maximum permitted weight of lorries was increased in February 2001 to 44 tonnes. All bridges have had to be assessed to see if they could cope safely with this increase.
Pending strengthening, public safety is maintained on those bridges assessed as weak by using temporary weight restrictions or other measures.
Work carried out under the strengthening programme gives priority to bridges on principal roads. For substandard bridges on the non-principal road network, decisions are made whether to restrict weights permanently rather than strengthen. Each bridge is considered on its merits taking into account safety, economic and environmental factors.