Select the sports coupe as your car and the Interstate track. On the two lane highway section of the track with the dirt median in the center, get a turbo boost. Use the turbo to gain speed. At the end of the stretch of road will be the green arrows directing you to the exit. Just off to the right of the arrows there will be a metal barrier. Hit it slightly to the right while doing the turbo boost and your car should fly over the barrier and into a ravine.