There are five miles of congestion on the A14 after one lane was closed on the westbound carriageway after a crash involving a car and two lorries.
The incident happened at about 6.15am between junctions 37 and 38 near Newmarket and Exning.
One of three lanes has been blocked as a result of the crash and there are delays of up to 40 minutes.
According to police, the blockage should be cleared "shortly".
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