A crash in Polegate on the A27 caused delays for motorists.
The smash is thought to have involved a bus and a car and happened at junction with Gainsborough Lane and the A27 Lewes Road.
One driver was treated by ambulance crews while the other was unhurt.
The road re-opened briefly at 9.30am, but was then shut an hour later for recovery work, before being fully re-opened at just after 11am.
The incident caused major traffic disruption in both directions of the A27 with cars re-routed via Jevington.