A motorcyclist suffered serious injuries in a freak incident at Parafield Gardens.
At 1.40pm on Saturday afternoon, the driver of the vehicle along Martins Rd saw the person on the ground.
Advertiser Understands that he fell off a bicycle and hit his head on the concrete.
Following treatment at the scene, a 57-year-old man from Parafield Gardens was taken to Royal Adelaide Hospital with life-threatening injuries. His condition is serious.
Martins Rd was heavily crowded with street bans while Major Crash officials inspected the site.
Anyone who has witnessed the incident or has footage of the dormitory is urged to call Crime Stoppers on 1800 333 000.