Reducing the speed limit on the Orwell Bridge during strong winds prevented three closures - which would have totalled 23 hours - in just one month.
Now fresh calls have been made to review the diversion route when the reduced speed limits cannot be used and the bridge does have to close - to avoid traffic going through the centre of Ipswich.
The matter was discussed on Thursday night at Ipswich Borough Council's scrutiny committee, where it was revealed that the £1.5m upgrade introduced in March prevented three closures in May alone.
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Previously, these storms would have forced the bridge to close for a total of 23 hours.
The new measures enable the speed limit over the bridge to be reduced from 60mph to 40mph when wind speeds reach between 45mph and 60mph.
Councillors at the committee, which has lobbied hard for improvements for more than five years, have welcomed the progress.
However, they requested that Highways England and Suffolk County Council return to the committee in the near future to address the outstanding problem of the diversion route for instances when wind speeds mean a bridge closure is still required.
Committee vice-chairwoman Sandra Gage said: “I am pleased with the early results of the use of the lower speed limit on the bridge – it will clearly significantly reduce the frequency that the bridge has to close.
“But there does need to be a Plan B, which is not really the solution we wanted – a northern bypass – but will have to do, and it is about Highways England and Suffolk County Council urgently reviewing the current official diversion route.
“It is wholly unacceptable for this route to be the A1214 through the centre of Ipswich.
"Roads such as Colchester Road, Chevallier Street, Yarmouth Road and London Road were deemed unsuitable for trunk road traffic over 40 years ago, hence the construction of the current bypass in the early 1980s.
“This route takes traffic along roads with poor air quality areas, which the highways authority is supposed to be addressing.
“Whenever there is an incident on any part of the route, including on the bridge, the role of the bypass is compromised and the traffic diverts through our town, causing gridlock and lost income.”
Suffolk Chamber of Commerce estimates that a single bridge closure costs the town’s economy £1m per day.
It too has echoed calls for a solution when winds are too high for the 40mph limit to be acceptable.
It is not yet clear when the two highways authorities will return to the borough council’s scrutiny committee to discuss the issue.
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