The collision with a Seat Leon occurred at 10am on Saturday May 22 on Castlegate, one of the town's main shopping streets.
The victim was a pedestrian aged in his 80s. He was taken to hospital with serious head and leg injuries.
The driver of the Seat Leon, a local woman in her 20s, was arrested on suspicion of driving a motor vehicle with a specified controlled drug above the specified limit. She has been released under investigation pending further enquiries.
Police are appealing for witnesses to the collision or anyone who recalls seeing the vehicle prior to the collision, or who has dashcam footage, to get in touch as soon as possible to assist the investigation.
Contact North Yorkshire Police on 101, select option 2, and ask for Jack Dodsworth, or email [email protected] quoting reference number 12210122895.