Police are appealing for witnesses following a potential hit-and-run in Chichester on Friday (August 23).
The incident took place at about 4.10pm on Friday at the junction of Sherbourne Road, and Oliver Whitby Road.
The cyclist, an 84-year local man, was taken by ambulance to St Richards Hospital, Chichester, with a serious head injury. He is currently in a stable condition, police have said.
A spokesman for Sussex Police said: "We are appealing for witnesses to a serious collision between a car and a pedal cycle in Chichester.
"It is believed that the car involved did not stop at the scene.
"Anyone who saw what happened or who has relevant dash-cam or closed circuit television (CCTV) images is asked to contact Sussex Police online, by emailing email@example.com or by phoning 101, quoting Operation Dartmoor.