Officers were called to a serious collision involving a van and taxi at 10.45pm last night on the M606, Bradford.
Two men aged 28 and 49 in the taxi were pronounced dead at the scene.
An 18-year-old male passenger in the van died in hospital this morning.
Another passenger from the van a 17 year old boy is in hospital with serious but not life threatening injuries.
The 15 year old driver has been arrested on suspicion of causing death by dangerous driving but remains in hospital with serious but not life threatening injuries.
Due to the nature of the incident West Yorkshire Police has informed the Independent Office for Police Conduct.