A motorcyclist is being treated by ambulance crews following a collision in Lewes.
Emergency services are dealing with the collision which involved a motorbike and a car on the A27 near the Southerham roundabout at Lewes, police said.
The motorcyclist is being treated by an ambulance crew and the driver is unhurt, police said.
Motorists are asked to avoid the area if possible.
It is hoped to have both carriageways open before the evening rush hour.
The incident happened just after 3pm today (Thursday July 24).
Anyone who witnessed the collision is asked to email firstname.lastname@example.org or call 101 quoting serial 1015 of 24/07.