When I was in high school our school put on a tech fair and we always participated in the mileage car race. They wouldn't allow 2 wheel only vehicles because it was still supposed to be near a car type configuration. We tried a 3 wheeler once that the operator could tilt/lean without the rest of the car in cornering but it did not gain us anything. That sure was a fun experience. Our cars were always 2 wheels up front and 1 in the rear. The last one we built we made the steer axle to have spring loaded spindle mounts. That car won that year and we got disqualified because the front axle didn't meet their rule wording. We think the school that won every year just threw a fit.