The number of council-owned road bridges deemed substandard rose 7% in the last year, new figures show.
Some 3,441 bridges in Britain were not fit to support the heaviest lorries in 2016/17, according to motoring research charity RAC Foundation.
This represents around one in every 22 of the 74,000 bridges on the local road network and is up from 3,203 the previous year.
Many of these structures have weight restrictions and others are under programmes of increased monitoring or managed decline.
Devon has the highest number of substandard bridges at 249, followed by Somerset (168), Essex (160) and Cornwall (144).
Some are substandard because they were built to earlier design standards, while others have deteriorated through age and use.
RAC Foundation director Steve Gooding said the figures were "unwelcome, if unsurprising".
He said: "The road maintenance crisis faced by financially beleaguered councils is often reported in terms of potholes to be filled, but this research hints at the wide spectrum of things needing attention, including blocked gullies, overgrown verges and, of course, fragile bridges."
The total cost of clearing the backlog of work on all bridges, including those that are substandard, was estimated at £5 billion, up from £3.9 billion a year earlier.
But annual council spending on bridges had fallen by 18% year-on-year to £367 million.
Mr Gooding said: "As council budgets continue to be squeezed by the growing pressure of social care, these numbers are a stark illustration of the gloomy consequences for the quality and integrity of our local networks."
The study was carried out in partnership with Adept, a group representing local authority bosses responsible for transport and other sectors.
Martin Tett, transport spokesman at the Local Government Association, representing more than 370 councils in England and Wales, insisted local authorities were "doing what they can" to maintain roads in the face of "increasing budgetary pressures".
He urged the Government to reinvest the equivalent of 2p per litre of existing fuel duty into local roads maintenance as well as provide "long-term and sustained investment".
On Tuesday, a bridge that features in Thomas Hardy's novel Tess of the D'Urbervilles partially collapsed into a river.
The Grade II* listed Wool Bridge was considered to be the best preserved Elizabethan bridge in Dorset, where it crosses the River Frome.
It was already closed to traffic except for cyclists.