Sussex Roads Police are investigating a multi-vehicle crash on the A24 between Findon and Washington that occurred around 8:45 am on Thursday, November 16.
The accident, involving three vehicles, led to the closure of the dual carriageway in both directions as emergency crews attended the scene.
One individual was severely injured and airlifted to the Royal Sussex Country Hospital.
Police are seeking witnesses and asking for any relevant CCTV or dashcam footage.
Information can be reported to Sussex Police online or via emailing: email@example.com and quoting serial 247 of 16/11.