Officers were called to Oldham Road at around 5.45pm on Saturday 26 April following reports of a serious collision involving a Toyota Prius and an electric scooter.
The rider of the scooter, a man in his 20s, was taken to hospital where he remains in a life threatening condition.
The driver of the car stayed at the scene and no arrests have been made.
Greater Manchester Police said its Serious Collision Investigation Unit is now working to establish the full circumstances.
Officers are asking anyone who witnessed the incident to come forward. They are also keen to speak to people who may have CCTV, dashcam or mobile phone footage from the area in the moments before the collision.
Anyone with information is asked to contact police on 0161 856 4741 quoting log 2474 of 26 April 2026. Information can also be shared through the force website reporting tools or anonymously via Crimestoppers on 0800 555 111.
