More than 3,000 council-maintained road bridges in Great Britain are substandard, according to research by the RAC Foundation.
It says analysis of data received from 199 of the 207 local highway authorities in England, Scotland and Wales found that 3,203 structures over 1.5m in span are not fit to carry the heaviest vehicles now seen on our roads, including lorries of up to 44 tonnes.
This means many of these bridges have weight restrictions. Others are under programmes of increased monitoring or even managed decline.
The Foundation has calculated that these 3,203 bridges represent 4.4% (about 1 in 23) of the roughly 72,000 bridges to be found on the local road network.
What’s more, the number of substandard bridges is 35% greater than that estimated by the RAC Foundation to have been substandard two years earlier.
Nearly half (47%) of bridges in Slough were substandard, while the proportion was more than a third in Bristol, Croydon and Islington.
“If money was no object, then councils would ideally want to bring 2,110 of these back up to standard,” the report says. “However, budget restrictions mean councils only anticipate 416 of these will have the necessary work carried out on them within the next five years.”
The report adds that the one-off cost of bringing all the substandard bridges back up to perfect condition would be around £890 million. This is the equivalent of £278,000 per structure.
The total cost of clearing the backlog of work on all bridges – including those that are substandard – is estimated at £3.9 billion, but that councils are currently spending just an eighth of that – an estimated £447 million – per year maintaining their entire bridge stock.
When the local authorities were asked what the biggest challenges they expected to face in the next 10 years in maintaining their bridges; “funding” and “skill shortages” were commonly cited.