An Air Ambulance has been called following a multi-vehicle crash on the A24 Horsham bypass near Broadbridge Heath.
The collision has taken place northbound at the junction with the A264.
The fire service said three crews, from Horsham, Partridge Green and Crawley, had been sent to the scene.
A spokesman for the Air Ambulance said crews were also currently in attendance after being called at about 2.40pm.
Long tailbacks have been reported on the dual carriageway and congestion is also being reported around the town.
More to follow.