Paramedics cut man out of car after four car pile-up

Paramedics have had to cut a man out of a car after a four-wheel drive was pushed on top of his vehicle in a chain-reaction crash at Klemzig.

CCTV captured the moment a ute was catapulted into the air, pushing another vehicle into oncoming traffic.

Four cars were involved in the collision, but incredibly no one was seriously harmed.

Witnesses told 9NEWS they feared that the crash could be fatal.

"Glad they are actually, you know, nobody got injured. As far as the car, they can fix it up, no problem," one witness named Terry told 9NEWS.

"The way the car was skid and gone another car on top, I thought maybe somebody died," Lalit Shirvalkar said.

A male driver aged in his 20s was trapped in his car.

Raminder Singh saw the crash and rushed to help.

"My heart is racing and I'm telling him 'you are alright' and he is telling me he is alright," he said.

Emergency crews had to smash through the car's front windscreen, then saw off the car's roof in order to free the driver.

He was then transported to Royal Adelaide Hospital with non-life threatening injuries.

The three other drivers involved were unharmed.

Roads were blocked for almost two hours following the collision, with police diverting traffic as the affected vehicles were towed from the scene.

Police are now trying to piece together what lead to the accident, and whether inattention, alcohol or speed played a part.