floorboard. They often have a gear shifter with an automatic clutch. The moped used to be a hybrid of the bicycle and the motorcycle, equipped with a small engine (usually a small two-stroke engine up to 50 cc, but occasionally an electric motor) and a bicycle drivetrain, and motive power can be supplied by the engine, the rider, or both. There are also Sport mopeds – a type of moped that resembles a sport bike. In many places, mopeds are subject to less stringent licensing than bikes with larger engines and are popular as very cheap motorbikes, with the pedals seeing next to no use. Mopeds were very popular in the United States during the fuel-crisis of the late 1970s and early 1980s, but their popularity has fallen off sharply since the mid-1980s. In response to rising fuel prices in the first decade of the 2000s, U.S. scooter and moped ridership saw a resurgence. Sales of motorcycles and scooters declined 43.2% in 2009, and continued to decrease in the first quarter of 2010, with scooter sales doing worst, down 13.3% compared to a 4.6% drop for all two-wheelers. Other types of small motorcycles include the minibike, monkey bike, Welbike, pocketbike, and pit bike. Enclosed and feet forwards Enclosed motorcycles include cabin motorcycles and streamliner motorcycles. Feet forwards motorcycles include the 1911 Wilkinson TMC and the 1918 Ner-A-Car. Contemporary examples include the Quasar, powered by a Reliant Robin engine, and the Peraves range powered mainly by BMW K Series engines. Utility Some motorcycles are specially adapted for specific job functions, such as those used by the ambulance, blood bikes, fire, and military services, and for specialized delivery services, such as pizza deliveries. Beginning in the 1960s with the Mountain Goat specialized motorcycles were developed for use on farms. The Motocrotte (or cainette) was used in Paris to collect dog waste with vacuum suction in the 1980s and 1990s, and was still in use in other French cities as of 2016. A derny is a motorized bicycle used for motor-paced cycling events. Tricycles While motorcycles typically have two wheels, some motorized tricycles are classed as three-wheeled motorcycles. Some brands have made various types of three-wheelers direct from the factory. Most of these vehicles are treated as motorcycles for registration or licensing purposes. Tilting three-wheelers keep all three wheels on the ground when they lean to negotiate curves. These include Honda's Gyro range,