Police were called at around 4.20am this morning when a Hyundai car crashed into a parked HGV on a residential street in Wakefield.
A spokeswoman said: "A woman and a man, both in their 20s, suffered potentially life-threatening injuries and were taken to Leeds General Infirmary."
Now investigators are appealing for witnesses to the incident in Lime Pit Lane, Stanley, at around 4.20am.
The white Hyundai car had been travelling towards Lake Lock Road when it hit an HGV parked at the side of the road.
Police Sergeant Martin Greasley, of West Yorkshire Police’s Safer Roads Team, said: “This was a very serious incident which has left two people with significant injuries.
“We are carrying out a range of enquiries but would appeal for anyone who witnessed the collision itself or saw a white Hyundai i20 driving in the area shortly before the collision, to get in touch.”
Lime Pit Lane was closed this morning while enquiries were carried out but it has since reopened.
Anyone who witnessed the collision is asked to contact the Safer Roads and Neighbourhood Support Team on 101, quoting log number 142 of 1 March.