The air ambulance has landed following a four-vehicle crash on a slip road of the M23.
The crash involves a yellow crane, blue skip, Fiat and fourth vehicle which is at this stage unknown.
It occurred shortly before 3.40pm, a Sussex Police spokesman said.
He said the crash was on the off-slip of the slip road, close to the traffic lights of the southbound carriageway near Pease Pottage.
The motorway is open but police said traffic was moving “very slowly” and are urging people to avoid the area.
The skip and the Fiat have been removed but the crane is still on site.
The driver of the crane, a 54-year-old from Worthing, has been taken to East Surrey Hospital by air ambulance.