Three-wheeled cars are not the norm. There’s no functional justification in producing a car that is fundamentally less stable than a four-wheeler, so a three-wheel design is a novelty nowadays.

Simply put, three-wheeled vehicles are classified as motorcycles in the U.S. Therefore, they don't need to undergo the expensive safety testing that four wheel cars do.

Toyota's three-wheeled i-Road, first launched at the Geneva Motor Show in 2013, is now undergoing a car sharing system trail run in Grenoble, France. The i-Road combines the handling of a ...