Emergency services were called to Bradford Road, Dewsbury, at around 10am this morning (Saturday) following the crash.
The collision involved a white BMW 420 coupe car.
Police are now appealing for witnesses following the fatal collision, which took place under a railway bridge near the Lidl supermarket.
A road closure is in place at the scene.
Sergeant Carl Quinn, of the Major Collision and Enquiry Team, said: "We are investigating this fatal collision and are appealing for witnesses. Anyone who saw the collision or the manner in which the BMW was being driven prior to it, is asked to contact the Major Collision and Enquiry Team on 101. 1
Police said a 21-year-old man has been arrested on suspicion of causing death by dangerous driving in connection with the incident, and is in police custody for questioning.