Police are appealing for witnesses and any relevant CCTV or dashcam footage following a collision on the A259 Ferring by-pass.
The incident happened at about 4pm on Thursday, March 16, on the westbound carriageway towards Angmering between Asda and the roundabout junction with the A280
It involved the rider of an Aprilla motorcycle and the driver of a blue BMW.
The rider, a 32-year-old man from Lancing, was taken to hospital with serious injuries, where he currently remains.
Officers are investigating the collision, and want anyone with relevant footage of the collision, or of the vehicles in the area in the run up to it, to come forward.
Information can be reported to Sussex Police online or on 101, or email collision.investigation@sussex.police.uk and quote Operation Hemmingway.
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