The two-car crash happened on Manchester Road in Huddersfield at 9.30am today (Tuesday).
A Vauxhall Corsa was turning right towards the Wickes Superstore when it crashed with a Mercedes Sprinter Minibus.
A 45-year-old man who was a passenger in the Vauxhall Corsa was taken to Leeds General Infirmary in a critical condition.
The driver of the car suffered minor injuries.
The driver of the Mercedes Sprinter Minibus, a 39-year-old man, was arrested at the scene on suspicion of drug driving.
He remains in police custody.
Police are appealing for anyone who saw the collision or saw vehicles prior to the collision to get in touch via 101 quoting log 446 of April 16.