Police are appealing for witnesses or anyone with dashcam footage following a serious collision on the A27 in Hammerpot around 1.25am on Tuesday, November 22.
A car collided with a stationary police car, which was assisting with a lane closure following a separate road collision two hours previous.
The road was closed in both directions so colleagues from West Sussex Fire and Rescue and the ambulance service could attend the scene.
A man who was driving the vehicle was taken to Royal Sussex County Hospital with serious, life threatening and life changing injuries, where he remains at this time.
The A27 has subsequently reopened.
Anyone witnesses to the collision or has dashcam footage which could assist officers with their investigation is asked to report it to police by emailing firstname.lastname@example.org quoting Operation Hutton.