Motorcycle

A motorcycle is broadly defined by law in most countries for the purposes of registration, taxation and rider licensing as a powered two-wheel motor vehicle. Most countries distinguish between mopeds of 49 cc and the more powerful, larger, vehicles (scooters do not count as a separate category). Many jurisdictions include some forms of three-wheelers as motorcycles.
Environmental impact
In 2007 and 2008, motorcycles and scooters, due to good fuel efficiency, attracted interest in the United States from environmentalists and those affected by increased fuel prices. Piaggio Group Americas supported this interest with the launch of a "Vespanomics" website and platform, citing lower per-mile carbon emissions of 0.4 lb/mile (113 g/km) less than the average car, a 65% reduction, and better fuel economy.