A bus (or omnibus or autobus) is a road vehicle designed to carry passengers. A bus generally carries more passengers than a minivan, and is used for different purposes. Buses are the most widely used mode of public transport, although buses also see use in a number of other applications, notably in tourism and as private transport. Buses come in various shapes and sizes, and can carry anywhere from 8 to 200 passengers, in varying levels of comfort. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses. A more luxurious version of all sizes of bus is the coach. Buses are usually powered by a diesel engine, although early buses were horse drawn, and experiments with steam buses also occurred. In parallel to the fully mobile bus, was use of the trolleybus. Limited uses and further research into alternative powertrain technologies for buses continues in parallel with the car industry. While historically buses around the world had, and still have, differences in design and appearance, in common with the car industry bus manufacturing is increasingly a globalised activity, with the same design of bus appearing on roads around the world. Buses, particularly for public transport, are increasingly designed for accessibility.
Since motorisation, the traditional configuration of a bus was an engine in the front and an entrance at the rear. Since the 1960s, with the transition to one man operation, buses in the developed world have taken the form of mid or rear-engined designs, with a minimum a single door at the front, or multiple doors, depending on need. Front-engined buses still persist for niche markets such as American school buses, some minibuses, and buses in less developed countries which may be derived from truck chassis, rather than purpose built bus designs.
The most common design of bus is a rigid single-decker bus with two axles, or if needed, a second rear axle. The midibus is a lighter and smaller purpose built development of the single deck bus, which emerged in the 1990s. The minibus, originally developed from van conversions, fulfils the lowest capacity needs of buses. Minibuses today are both still derived from vans, or built specifically as minibuses. For carrying capacities larger than catered for single-deckers is generally achieved by the use of the double-decker bus or the articulated bus, the preference of which varies from country to country. A double-decker is a rigid single-decker bus but with an extra upper deck, with the decks joined by a staircase, usually at the front in modern vehicles, but in the rear for historical designs. Larger double-deckers can feature both a front and rear stair case. Articulated buses take the form of single-decker bus with a 'trailer' portion attached. In articulated buses, drive can be through the front or rear section's axles. In modern articulated buses, it is possible to walk between the front and rear sections through an "accordion" joint.
For many new bus fleets, there is an increasing shift to low-floor buses (see Accessibility), although again in other parts of the world, high floors can still be encountered. The move to low floor has all but eliminated the mid-engined design, although some coaches still have mid mounted engines.
While most bus and coach designs will normally have two axles, (or three for articulated buses), buses and coaches may often be fitted with additional axles to accommodate extra length/weight. This is common on three axle rigid coaches. Often this feature is subject to local vehicle regulations. An uncommon departure from the normal standard rigid or articulated buses, there also exist limited instances of bi-articulated buses, and passenger carrying trailers - either towed behind a conventional bus (a bus trailer), or hauled as a trailer by a truck (a trailer bus).
A coach or motorcoach describes a more luxurious version of a bus, designed for more comfortable or longer distance travel. Coaches can come in the same general configurations as buses, as single or double-deckers, articulated, or small 'mini-coaches'. Coaches have a higher floor level than buses, to allow for under-floor storage of luggage. The larger coach designs are often heavier and higher powered than the equivalent sized buses, to allow higher speed motorway or autoroute operation and increased luggage carrying capacity. Coaches do not generally allow for standing passengers, and feature upholstered high backed individual seating. Coaches often contain passenger comforts such reclining seats, hand luggage storage, a toilet and audio-visual entertainment systems. As a low-cost version of a coach, a bus may be fitted with coach style higher backed more comfortable seats, termed ‘dual purposed’ bodywork. These may be used on long distance public transport services, or as low cost charter coaches. Increasingly in some areas, individual upholstered coach style seating, either fully high backed or standard bus seat height, is being employed on higher specification transit buses, sometimes with leather upholstery.
Historically, accessible buses were specially modified standard buses, as mobility buses, produced by post manufacture, or niche manufacturers. Latterly, many standard bus types have become accessible, although mobility buses are still in production, usually as minibus size vehicles. Mobility bus modifications are usually to add a side or rear wheelchair lift and add doors, or widen existing doors, or add an extendible access ramp. For standard buses a major part of accessibility is achieved by the low-floor bus design, although for coaches accessibility is being achieved through wheelchair lifts due to their higher floor level. Easier access for wheelchairs, pushchairs and the elderly can also be achieved through the use of kneeling air suspension and electrically or hydraulically extended under-floor ramps. Other accessibility features include wide entrances and interior gangways, for wheelchairs and push chairs, and brightly coloured interior fittings and clear destination displays to aid the visually impaired.
Alternatives to the dominance of diesel combustion engine power of conventional buses since the 1930s are being investigated, and have been used in service or trialled in many locations. The electric bus has been the most commonly investigated, with the hybrid electric bus and fuel cell bus also being emerging technologies, along with combinations of power sources/storage. The gyrobus is another system which has historically trialled the use of energy stored as flywheel momentum or hydraulic pressure, and is still being investigated. The conventional combustion model is also being investigated with bio-diesel and hydrogen as alternative fuels.
Public transport forms the major use of buses and coaches, designed for the transport of the general public as a public service, rather than the private hire or use of buses for transport or other purposes. The use and design of public transport buses varies around the world, and utilises the entire range of bus designs and capacities. The design of buses and coaches is often specialised to a particular type of service. Buses may operated fixed routes, or be used as flexible services. Public buses can be organised in large fleets or as small concerns, and be publicly or privately owned and operated.
The transit bus is the predominant design of public bus, which features specific features to allow use as a public transport vehicle. Transit buses have utilitarian fittings designed for efficient movement of large numbers of people, and often have multiple doors. A dual purpose bus is a transit bus fitted with coach style higher backed more comfortable seats, used on longer distance routes where standing passengers are not likely to be present. Specially adapted mobility buses may be used on specialist services for the transport of passengers with mobility issues (See Accessibility section).
High capacity bus rapid transit (BRT) services may use the bi-articulated bus, an extension of the articulated bus concept with two trailer sections. BRT schemes (and other uses) may also use tram style buses, which certain bus manufacturers have tried to emulate the tram with modified articulated bus designs, with features such as a ‘pilot’ style driving position and streamlined styling, for example the Wright StreetCar and the Irisbus Civis. Guided buses are fitted with technology to allow them to run in designated guideways, allowing the controlled alignment at bus stops and less space taken up by guided lanes than conventional roads or bus lanes. Guidance can be mechanical, optical or electromagnetic. Guidance is often, but not exclusively, employed as part of a BRT scheme. Extensions of the guided technology include the Guided Light Transit and Translohr systems, although these are more often termed 'rubber tyred trams' as they have limited or no mobility away from their guideways.
Buses are often used for advertising, political campaigning, Public service announcements, public relations or promotional purposes. These may take the form of temporary charter hire of service buses, or the temporary or permanent conversion and operation of buses, usually of second-hand buses. Extreme examples include converting the bus with displays and decorations or awnings and fittings. Interiors may be fitted out for exhibition or information purposes with special equipment and/or audio visual devices.
Bus advertising takes many forms, often as interior and exterior adverts and all-over advertising liveries. The practice often extends into the exclusive private hire and use of a bus to promote a brand or product, appearing at large public events, or touring busy streets. The bus is sometimes staffed by promotions personnel, giving out free gifts. Campaign buses are often specially decorated for a political campaign or other social awareness information campaign, designed to bring a specific message to different areas, and/or used to transport campaign personnel to local areas/meetings. Exhibition buses are often sent to public events such as fairs and festivals for purposes such as recruitment campaigns, for example by private companies or the armed forces. Complex urban planning proposals may be organised into a mobile exhibition bus for the purposes of public consultation.
Airport operators make use of special airside airport buses for crew and passenger transport in the secure airside parts of an airport. Some public authorities, police forces and military forces make use of armoured buses where there is a special need to provide increased passenger protection. Police departments make use of police buses for a variety of reasons, such as prisoner transport, officer transport, temporary detention facilities and as command and control vehicles. Many are drawn from retired school or service buses.
In local sightseeing, City Sightseeing is the largest operator of local tour buses, operating on a franchised basis all over the world. Specialist tour buses are also often owned and operated by safari parks and other theme parks or resorts. Longer distance tours are also carried out by bus, either on a turn up and go basis or through a tour operator, and usually allow disembarkation from the bus to allow touring of sites of interest on foot. These may be day trips or longer excursions incorporating hotel stays. Tour buses will often carry a tour guide, although the driver or a pre-recorded audio commentary may also perform this function. The tour operator may itself be a subsidiary of a bus operating company that operates buses and coaches for other uses, or an independent company that charters buses or coaches. Commuter transport operators may also use their coaches to conduct tours within the target city between the morning and evening commuter transport journey.
Buses and coaches are also a common component of the wider package holiday industry, providing private airport transfers (in addition to general airport buses) and organised tours and day trips for holidaymakers on the package.
Public long distance coach networks are also often used as a low-cost method of travel by students or young people travelling the world. Some companies such as Topdeck Travel were set up to specifically use buses to drive the hippie trail or travel to places like north Africa.
In many tourist or travel destinations, a bus is part of the tourist attraction, such as the North American tourist trolleys, London’s Routemaster heritage routes, or the customised buses of Malta, Asia and the Americas.
Most public or private buses and coaches, once they have reached the end of their service with one or more operators, are sent to the wrecking yard for breaking up for scrap and spare parts. Some buses, while not economical to keep running as service buses, are often converted in some way for use by the operator, or another user, for purposes other than revenue earning transport. Much like old cars and trucks, buses often pass through a dealership where they can be bought for a price or at auction.
Bus operators will often find it economical to convert retired buses to use as permanent training buses for driver training, rather than taking a regular service bus out of use. Some large operators have in the past also converted retired buses into tow bus vehicles, to act as tow trucks. With the outsourcing of maintenance staff and facilities, the increase in company health and safety regulations, and the increasing curb weights of buses, many operators now contract their towing needs to a professional vehicle recovery company.
Many retired buses have been converted to static or mobile cafés, often using historic buses as a tourist attraction. Food is also provided from a catering bus, in which a bus is converted into a mobile canteen and break room. These are commonly seen at external filming locations to feed the cast and crew, and at other large events to feed staff. Some organisations adapt and operate playbuses or learning buses to provide a playground or learning environments to children who might not have access to proper play areas. A Routemaster ex-London bus has been converted to a mobile theatre and catwalk fashion show.
As with the auto-industry, into the 20th century, bus manufacturing is increasingly a globalised activity, with manufacturers producing buses far from their intended market to exploit labour and material cost advantages. As with the car industry, new models are often exhibited by manufacturers at prestigious industry shows to gain new orders.
After the Second World War, manufacturers in Europe and the Far East, such as Mercedes-Benz buses and Mitsubishi Fuso expanded into other continents influencing the use of buses previously served by local types. Use of buses around the world has also been influenced by colonial associations or political alliances between countries. Several of the Commonwealth nations followed the British lead and sourced buses from British manufacturers, leading to a prevalence of double-decker buses. Several Soviet countries adopted trolleybus systems, and their manufacturers such as Trolza exported trolleybuses to other friendly states.
The buses to be found in countries around the world often reflect the quality of the local road network, with high floor resilient truck based designs prevalent in several less developed countries where buses are subject to tough operating conditions. Population density also has a major impact, where dense urbanisation such as in Japan and the far east has led to the adoption of high capacity long multi-axle buses, often double-deckers, while South America and China are implementing large numbers of articulated buses for bus rapid transit schemes.
Rather than being scrapped or converted for other uses, sometimes retired buses are saved for preservation. This can be done by individuals, volunteer preservation groups or charitable trusts, museums, or sometimes by the operator themselves as part of a heritage fleet. These buses often need to undergo a degree of vehicle restoration to restore them to their original condition, and will have their livery and other details such as internal notices and rollsigns restored to be authentic to a specific time in the buses actual history. Some buses that undergo preservation are rescued from a state of great disrepair, while others enter preservation with very little wrong with them. As with other historic vehicles, many preserved buses either in a working or static state form part of the collections of transport museums. Working buses will often be exhibited at rallies and events, and are also used as charter buses. While many preserved buses are quite old or even vintage, in some cases relatively new examples of a bus type can enter restoration, while in service examples are still in use by other operators. This often happens when a change in design or operating practice, such as the switch to one man operation or low floor technology, renders some buses redundant while still relatively new.
Bus liveries are commonly used in bus advertising, by fully or partially using a bus livery as a mobile billboard. This greatly increased and became more complex with vinyl technology. Other special use buses may also wear special schemes, such as training buses, school buses, tour buses, product promotion buses, parade buses, and political or public awareness campaign buses.