The man was seriously injured in the incident, which happened at around 7.30pm in Old London Road on Friday evening (January 21).
The road was closed for around five hours while fire crews extracted the driver from the silver hatchback, and paramedics treated him at the scene.
Officers said he was taken to hospital with serious, potentially life-changing injuries.
A spokesperson for Sussex Police said today (January 27): “The casualty remains in hospital with serious injuries, but is in a stable condition. Anyone with information which can help officers with their investigation is asked to email [email protected] or call police on 101 quoting serial number 1115 of 21/01.”