The 35-year-old was struck by a black BMW 4 series at around 1.10am on Sunday morning at the junction of Lodge Road and Spear Road in Southampton.
The female was rushed to Southampton General Hospital where she remains critically ill.
Police are now trying to track down the 25-year-old driver of the car, who is from Southampton. He is not thought to have suffered any injuries.
Officers are now appealing for information from anyone who witnessed the incident.
Anyone with information should call Hampshire Constabulary on 101 quoting Operation Oblong.
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