Drivers are being warned they could face disruption as a series of overnight works take place in the coming weeks.
It comes as Highways England carries out around 20 nights of maintenance works to the A47 Bascule Bridge in Lowestoft.
Highways chiefs plan to carry out the overnight works between Monday, October 28 and November 24 - with drivers likely to face delays as traffic is diverted.
In a letter sent to nearby residents about the A47 works on the Bascule Bridge, Highways England said they would be "undertaking necessary improvement works on the A47 to replace one of the motors that helps lift Bascule Bridge".
It adds: "These road improvements are necessary to maintain the strategic road network along the A47.
"This will add benefits, such as a longer life span of the bridge and an improved journey for our customers."
The works are scheduled to take place overnight from 8pm to 6am each night, including weekends, between October 28 and November 24.
However, no works are expected to take place on Saturday, November 9.
With the bridge set to be temporarily closed, a spokesman for Highways England said: "The work we plan to do on the A47 Bascule Bridge in Lowestoft is likely to last over a two to three-week period.
"Work will take place overnight and traffic will be diverted round the town to avoid the area.
"A special bus service will be in place for pedestrians and cyclists."
A statement on the First Norfolk and Suffolk buses website said that due to the closures of the Bascule Bridge for repair works, "evening service 101 and X21 journeys will be diverted after 8pm" for about four weeks, starting on Monday, October 28.
It adds: "X21 buses departing Lowestoft after 8pm and departing Norwich from 7pm onwards will be diverted along Waveney Drive, Victoria Road, Oulton Broad, Normanston Drive, Peto Way and Denmark Road.
"Service 101 will follow the same diversion route from Kirkley Run, then Victoria Road. 101 will not stop on Waveney Drive or near Asda.
"The bus stops at Station Square (inbound) and Waveney Road (outbound) won't be served after 8pm.
"We are sorry for any inconvenience."
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