An Adelaide man has recounted the moment he came close to death, after a person put large rocks on a busy expressway.

Josh Nicolson was driving 100 km/h along the Southern Expressway when he hit 12 rocks that had been scattered across the road.

"It was a really dark area so you couldn't really see them up until the point where you got pretty close to them and by that stage it's too late," Mr Nicolson told 9News.

He managed to pull over, and along with another driver, the pair began stopping traffic.

"I started pulling the rocks off the road and once the traffic was stopped the other guys helped," he said.

Mr Nicolson's car wasn't seriously damaged, however four other vehicles had their tyres blown.

"When I saw the guy in the Corolla, his car just bounced right over it…I think it's just pure luck no one was seriously hurt," he said.

Detectives are urging witnesses to come forward so they can track down the offenders.

Source: 9News https://www.9news.com.au/national/cars-damaged-in-adelaide-after-large-rocks-placed-on-southern-expressway/22337ac0-b009-4172-94fe-34eb3e434b5a