Bridges A bridge is considered to be any structure that carries the highway over a river, canal, railway or footpath. A bridge can also carry a railway or footpath over the highway. For the purpose of classifying Trafford’s highway assets, the term ‘bridges’ is also typically assumed to include other highway structures such as some retaining walls, gantries and culverts. Trafford Council is the Highway Authority, Technical Approval Authority and the Bridge Authority for highway structures in the borough of Trafford. Trafford Council owns, is responsible for, or has some involvement with around 400 highway bridges. There are also other bridge owners/authorities, such as Highway England, Network Rail and Environment Agency. The maximum permitted weight of normal traffic vehicles was increased in January 2018 up to 45.5 tonnes.