The Brighton bypass was closed for much of the morning rush-hour period after a crash near the Southwick tunnel (Friday 8 June).
A woman was taken to the Royal Sussex County Hospital in Brighton with neck injuries after the crash on the A27 between the Holmbush roundabout and the Hangleton turn-off at about 5am.
The eastbound road was closed for more than three hours while firefighters cut her out of her car and Sussex Police investigators gathered forensic evidence.
The crash is believed to have happened when one driver tried to avoid a dead badger in the road.
Sussex Police said that the crash involved a Mazda, being driven by the woman, and a Vauxhall Corsa.
Anyone who saw the crash is asked to contact Sussex Police on 101.