Emergency services are dealing with a serious collision involving a motorbike and two cars, say police.
A police spokesman said the collision happed in Gatwick Road, Crawley, just before 8.15am today (Wednesday May 3).
Gatwick Road and Manor Road have been closed in both directions, according to police.
A police spokesman said: “The air ambulance has landed and there are no other details available at this time.”
Drivers and bus passengers heading north towards Manor Royal from Hazelwick Tesco Extra saw paramedics perform CPR on someone in the middle of the road.
A fire engine, several police cars and teams of paramedics were all on the scene from about 8am.
A bus passenger said: “We can see paramedics trying to save someone’s life while loads of emergency vehicles whizz pass. I hope they’ll be OK.
“I’m only going to meet friends, but there are school pupils and commuters caught up in the queues, as well as several air cabin crew anxious to catch flights.
“We’ve been at a standstill for about half an hour. Traffic must be all the way down to Three Bridges station by now.”