Sussex Police said the emergency services were dealing with a van fire and car that had left the road – and the driver was trapped.
West Sussex Fire & Rescue Service confirmed crews from Burgess Hill and Henfield attended the van fire – northbound on the A23 between Muddleswood and Hickstead, at 10.18am.
It added that a car left the road and went into a hedgerow, between Pyecombe and Muddleswood, northbound.
“One person was trapped, but the casualty self-extricated under South East Coast Ambulance Service’s supervision,” said a spokesman.
“Two fire engines from Brighton attended at 10.39am.”