Limousine services have been defined as a luxurious service, a luxury sedan, driven by a professional chauffeur. Limousine is the most expensive liveried vehicle, often associated with extreme wealth. Limousine services are often hired during special events, most commonly weddings, proms and bachelor parties. Limousine services are also used by large companies to transport executives, and by broadcasters to transport guests. Limousines usually have to be booked in advance and are not hired on the spot as taxi cabs can be.