The Orwell Bridge was closed for about eight hours due to high winds, causing traffic congestion in Ipswich.
Weather forecasters said winds speeds exceeded 60mph (96km/h) across Suffolk due to Storm Gareth.
The A14, which passes over the bridge, south of Ipswich, was shut by Highways England at about 08:00 GMT between junctions 56 and 57.
Traffic was gradually allowed back onto the river crossing from about 15:45, as diversions were removed.
Latest wind speed readings on the bridge have reached 60mph and above. Until speeds decrease significantly, the closure will remain in place in both directions. Please allow extra time for your journey if you're travelling this morning as the diversion route is heavily congested.— Highways England (@HighwaysEAST) March 13, 2019
On Twitter, motorists said they had braced themselves for "traffic chaos" through Ipswich.
One wrote: "As the Orwell bridge is closed due to wind I better gets the kids scooter out as is the only way to get around town."
Another said: "Ipswich roads stuffed today."
Options to prevent the gridlock caused by the Orwell Bridge closure:
- Northern Bypass: A route connecting the A12 and the A14 running north of Ipswich has been discussed for decades. Options include an A14-style dual carriageway, an 'urban' dual carriageway with roundabouts or a wide single-lane road like Colchester Road or Valley Road
- Upper Orwell Crossings: The multi-million pound project, now cancelled due to spiralling costs, would have seen a bridge connecting the banks of the Orwell around the Holywells area of Ipswich with the Wherstead Road side
- Wind breaks: Highways England commissioned a thorough aerodynamic study of the Orwell Bridge. It will utilise wind tunnel testing and bridge modelling to assess the impact of different wind speeds and directions. It will inform any future measures for wind-related bridge closures
- Reduced speed limits: The bridge already has a 60mph speed limit, but questions have been asked as to whether allowing cars to continue at, for example, 30mph would reduce the impact of the wind. In theory the slower the vehicle travels, the more stable it is - but this will still largely be dictated by the wind speeds
- Allowing cars to continue on the bridge: High-sided vehicles such as coaches and lorries are more exposed to the winds across the bridge than cars. With that in mind, one area for assessment is diverting high sided vehicles off the bridge but allowing cars to continue using it
- Additional diversions: Currently just one diversion is publicised. Some Ipswich councillors have called for traffic to be diverted off the A14 earlier when heading eastbound, so cars get onto the road network outside of the A14 well before reaching Ipswich
It took more than an hour to close the Orwell Bridge, with traffic diverted via the A1156, A1189 and A1214 through Ipswich.
According to Highways England protocol, advisory restrictions are put in place with wind speeds between 45mph (72km/h) and 60mph (96km/h), and closures above 60mph.
The bridge has been known to close with wind speeds of 49mph (79km/h).
Closures are made to prevent lorries being blown over.