The Highways Agency has said cavities underneath the A14 at the Rookery crossroads could be responsible for subsidance over the past months.
Radar equipment has been used to determine the problem, which led to speed restrictions and repairs having to be carried out on the westbound carriageway in October.
Now, the organisation is planning to fill in the cavities short term in order to determine a permanent solution to the problems.
The subsidance occurred on two occasions after a 12 million improvement scheme, creating a two level junction and underpass, was completed by Mowlem Plc, now Carrillion, and opened in 2006.
However, problems later appeared on the westbound stretch of road between the Rougham interchange and Two Mile Spinney.
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