Travel reports show the dual carriageway has now been re-opened, with residual delays travelling eastbound.
Police said officers were called to the scene at around 5.10pm near the Crossbush Inn to find the car ‘well alight’.
The road was closed between The Causeway and the A284 Lyminster Road while emergency services attended.
A spokesman for the fire service said a crew from Arundel used two breathing apparatus and a hose reel to put out the fire and there were no reported injuries.