North Yorkshire Police officers were called to a collision involving a red Volkswagen Lupo and the road-sweeper on the B6480 at High Bentham near to the junction of Bent Lane at 11.34am on Saturday.
Emergency services were dealing with the injured driver of the Lupo when the road-sweeper left the scene.
But it later crashed on the A65 at Austwick, causing the driver serious injury, including a fractured ankle, a broken rib and fractured vertebrae. He was taken to Airedale Hospital.
The woman driver of the Lupo was taken to Airedale Hospital with possible a suspected rib fracture.
The driver of the road-sweeper tested positive on a roadside breathalyser is currently under investigation on suspicion of drink driving.
Police are appealing for anyone who may have witnessed the collision in either location, the manner of driving of either vehicle or who may have dash-cam footage that could assist the police investigation, to come forward.
Call North Yorkshire Police on 101 and pass the information to the Force Control Room, quoting reference 12190042962 or contact [email protected]