Cologne, Germany  - Police praised Thursday a van-driver who successfully stopped a speeding car on a German highway after its driver had suffered a fatal heart attack at the wheel.

As the car in the fast lane veered to its left and skidded along a metal safety barrier, the alert van-man, 39, pulled out to the right, overtook it and saw the driver slumped over the wheel.

He placed his van in front of the out-of-control car, allowed it to gently hit the rear end and then applied the brakes hard.

Ambulance crews managed to reanimate the car driver, 50, but he died shortly after in hospital of the effects of the heart attack.

German police said the Wednesday incident near Cologne might have ended as a horrific head-on collision if the hero, who has experience of emergencies as a volunteer fire-fighter, had not acted.

He drove away in the slightly crumpled van, which belongs to his employer. (dpa)