The A27 has been reopened after a police incident closed the road westbound for more than an hour this morning.
The main route was initially closed in both directions at Falmer at 6.40am.
The eastbound carriageway was reopened 15 minutes later, but was closed westbound until 8am.
At its worst, traffic was reported to be queuing back for three miles back towards Lewes.
Traffic was being diverted into Brighton along Lewes Road, where Brighton and Hove Buses also reported long delays, affecting services.
The road was while police negotiated with a man who was on the wrong side of the barrier at a bridge over the road.
He agreed to get down and was taken to hospital.
See the latest news headlines from The Argus:
- Hospital facing charge over legionnaires' disease case
- Lido restoration plans wins £2.3m cash boost
- Train delays due to flooded railway tunnel
- UPDATE: Man who fell 11 storeys from high rise had cancer
- Doctor charged with sexually assaulting 16-year-old patient