Police are appealing for witnesses to a fatal collision involving a motorcyclist at Stopham, near Pulborough, on Saturday (11 March).
Emergency services were called to the A283 with the junction of Lea Farm Lane at about 11.15am.
Despite the efforts of paramedics, the motorcyclist, a man, died at the scene.
Sergeant Chris Ambrose said: "We are investigating the circumstances but would urgently like to trace the driver of a red SUV 4x4 vehicle who could be a significant witness to the incident.
"If you were the driver or who have any information which could help our investigation, please email email@example.com quoting Operation Broad."