About 9.50am (Wednesday 5 July 2023), emergency services were called to the intersection of Castle Hill Road and Church Street at West Pennant Hills, following reports a pedestrian was struck by a car.
The pedestrian, an 83-year-old man, was taken to Westmead Hospital in a critical condition.
The driver, a 67-year-old man, was not injured and was taken to Westmead Hospital for mandatory testing.
Officers from The Hills Police Area Command established a crime scene and will investigate the circumstances surrounding the incident.
As inquiries continue, anyone with dashcam vision or further information about the crash is urged to come forward.
Traffic diversions are in place, visit livetraffic.com for more information.
Anyone with information about this incident is urged to contact Crime Stoppers: 1800 333 000 or https://nsw.crimestoppers.com.au. Information is treated in strict confidence. The public is reminded not to report information via NSW Police social media pages.