A motorcyclist who suffered serious injuries after colliding with a wall and a parked car on Pontefract Road in Knottingley remains in a critical condition.
Emergency services were called to the scene , close to the junction with the A162 Ferrybridge Bypass, at around 4am on Monday.
Police said initial enquiries suggest the motorbike was stolen.
The rider, a 26-year-old man, was taken to Leeds General Infirmary by ambulance with life-threatening injuries.
Police said the rider lost control of the blue Yamaha motorbike and collided with a wall and parked car.
Pontefract Road was closed while police and paramedics dealt with the incident.
PC Daniel Baldwin said: “We would urge anyone who has seen this collision or thinks they have seen this vehicle immediately prior to the collision to call the Western Area Safer Roads Team on 101.”