Lotus had introduced the concept of ground effect to the Formula One world championship in with their fast, but not always reliable, Type 78. Peter Wright and Colin Chapman had discovered that by carefully shaping the underside of the car, they could accelerate the air passing under the car, thereby reducing the air pressure under the car relative to that over it and pushing the tyres down harder onto the track. The increased downforce gave more grip and thus higher cornering speeds. Ground effect had the great advantage of being a low drag solution, unlike conventional wings, meaning that the increased cornering ability was not compromised by a decrease in straight line speed. In Lotus ironed out the reliability problems and further developed the concept from relatively simple sidepods with a wing profile into full venturi tunnels under the car. As soon as they appeared at Zolder, the black and gold Type 79s of Mario Andretti and Ronnie Peterson outpaced the opposition by a comfortable margin.