A chauffeur is an individual who operates any self-propelled vehicle (automobile) for a profession. While the term may refer to anybody who drives for a living, it usually implies a driver of an elegant passenger vehicle such as a horse-drawn carriage, luxury sedan, motor coach, or especially a limousine; those who operate non-passenger vehicles are generally referred to as “drivers” (as in bus drivers and truck drivers). In some countries, particularly developing nations where a ready supply of labor ensures that even the middle classes can afford domestic staff and among the wealthy, the chauffeur may simply be called the “driver.” “Chaffeur” is the modern French masculine term (noun/verb) derived from the meaning “he who heats”. The earliest automobiles, like their railroad and sea vessel counterparts, were steam-powered and required the driver to pre-heat the engine to produce energy, thus, the French term for stoker was adapted.[citation needed] People currently sometimes employ chauffeurs full-time to drive themselves in their own personal vehicles, yet there are also professional services offering limousines or rental cars driven by chauffeurs. This is very similar to but more luxurious than taking a taxicab. A variety of benefits are cited for using chauffeurs, including convenience, productivity and time savings, and driving safety for businesspeople and seniors. Indeed, insurance costs for luxury vehicles are often lower if the designated driver is a chauffeur. The requirements to be a chauffeur vary in geography and vehicle size or type, with many of these requirements established at the state or municipal level (US). In addition to a standard driver’s license, some areas require a chauffeur to obtain an additional professional license, which frequently sets certain numerous minimum standards for age, driving experience and record, local geographic knowledge, and indigenous security and operational procedures