A junction has closed for two weeks while preparations for Lowestoft's third crossing continue.
Diversions are in place for the junction of Durban Road with Waveney Drive, with work expected to take two weeks, finishing on January 25.
The junction will be permanently closed once construction of the Gull Wing bridge begins later this year.
A spokesperson for the project team said: "The work is being carried out by Farrans and Suffolk County Council, who are drilling exploratory holes to check locations of utilities, such as water services.
"This is part of the preparation work for the construction of the Gull Wing bridge.
"Later in the year, the junction will be closed permanently once construction is under way."
The £126.75m bridge was given the final seal of approval by the government in November, with the bridge planned to open in the summer of 2023, ending more than 100 years of waiting.
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