The maintenance backlog for council-owned road bridges in Britain has increased by a third in 12 months, new figures show.
An estimated £6.7bn is needed to bring all the structures up to scratch, according to analysis of 2017/18 data by motoring research charity the RAC Foundation.
Lancashire County Council has 77 bridges with weight restrictions, the seventh highest figure.
That is down from the 104 flagged up last year, when the council said many of the restrictions are needed for “historical reasons”.
Some are substandard because they were built to earlier design standards, while others have deteriorated through age and use.
Between them, local authorities say they would ideally want to bring 2,026 of these bridges back to full carrying capacity.
RAC Foundation director Steve Gooding said establishing the condition of highway bridges is a “litmus test for the condition of our road network” and described the findings as “worrying”.
He added: “While we should draw some comfort from the good knowledge highway authorities have about the strength and structural integrity of their bridges, the fact is that many thousands are subject to enhanced monitoring, speed and weight restrictions, and the cost of bringing them up to scratch is continuing to mount.
"Ancient bridges on rural back roads might not be the highest priority for repair, but the risk we run is that substandard structures on some roads result in heavier vehicles having to make lengthy detours.”
Devon has the highest number of substandard bridges - with a total of 244 needing repairs.