Toad Turnpike is the track you groan at. A normal figure-8 dumped with cars and 18-wheelers is quite a challenge if you don't have a racer that can handle well. To win, you must be able to swerve and dive in between traffic, all with the risk of exploding if you hit a vehicle. The item boxes are strategically placed on alcoves along the track.
When you start out, the game places you and the racers on a small section cut off from the main track, so you don't get bombarded with automobiles at the start. If you go to the item lines on the side of the road, be careful not to be trapped by a truck, as this will cost precious time. Use a grab-and-go strategy, so as not to be locked in. If you're hit on the track, try to get moving as fast as possible, for both time and the threat of being pummeled by a car. When you're behind a racer, check behind his kart. If there is a vehicle, try crippling them with a red shell or banana, as this will cause his kart to crash twice. Bananas are a great tool on this course.
Practice makes perfect (or at least better)!