The occupants of a car fled after the vehicle had been involved in a collision near Bradford.
Police are appealing for witnesses after people "failed to stop" after a crash which left two cars "extensively damaged" in Thornbury in the early hours of today.
The collision involving a silver Vauxhall Astra and a red Toyota Yaris occurred at around 12.10am on Leeds Road.
The Astra had been travelling out of Bradford in the direction of Thornbury at the time.
A West Yorkshire Police spokesperson said: "The occupants of the Astra fled the scene on foot towards Bradford. One of the occupants is believed to have been injured.
"The driver of the Yaris, a woman in her 20s, remained at the scene and was uninjured in the collision. Both vehicles were extensively damaged."
Police are appealing for anyone with any information, anyone who witnessed the collision or anyone who saw the silver Astra before the crash, to get in touch with officers.
Anyone with information is asked to contact PC 2526 Riley or PC 2589 Darren Wood of the Safer Roads team on 101, quoting log number 13 of September 19.
Information can also be passed anonymously to Crimestoppers on 0800 555 111.