Bus rapid transit

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This article is about high-capacity bus transit systems. For lower-order transit systems, see Matatu and bus; for higher quality and capacity see tram, light rail and rapid transit.

Image:Silverline-courthouse.jpeg Image:DSC03021.JPG Bus rapid transit (BRT) is a broad term given to a variety of different transportation systems that, through infrastructural and scheduling improvements, attempt to use buses to provide a service that is of a higher quality than an ordinary bus line. Each BRT system utilizes different improvements, although many improvements are shared by many BRT systems. The goal of such systems is to at least approach the service quality of rail transit while still enjoying the cost savings of bus transit. The expression "BRT" is mainly used in North America; elsewhere, one may speak of Quality Bus or simply bus service while raising the quality.

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Etymology

"Bus rapid transit" takes part of its name from "Rapid Transit" which describes a high-capacity rail transport system with its own right-of-way, its alignment often being elevated or running in tunnels, and typically running long trains at short headways of a few minutes. Because of the name similarity one tends to associate the merits of "Rapid Transit" also with the newer "BRT" expression.

The BRT term encompasses a broad variety of modes, including those known or formerly known as express buses, limited busways and rapid busways.

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What makes a BRT

These bus systems can come in a variety of different forms, from dedicated busways that have their own rights-of-way (e.g., Ottawa's Transitway or the Los Angeles LACMTA Orange Line) to bus services that utilize HOV lanes and dedicated freeway lanes (e.g., Honolulu's CityExpress) to limited stop buses on pre-existing routes.

An ideal bus rapid transit service would be expected to include some or all of the following features:

  • Bus-dedicated, grade-separated right-of-way: Right-of-way may be separated from all other traffic and dedicated to bus use. Such right of way may be elevated; on rare occasions, the right of way may be modified rail right of way.
  • Bus streets and busways: A bus street or transit mall can be created in an urban center by dedicating all lanes of a city street to the exclusive use of buses.
  • Bus lanes: A lane on an urban arterial or city street is reserved for the exclusive or near-exclusive use of buses.
  • Bus signal preference and preemption: Preferential treatment of buses at intersections can involve the extension of green time or actuation of the green light at signalized intersections upon detection of an approaching bus. Intersection priority can be particularly helpful when implemented in conjunction with bus lanes or streets, because general-purpose traffic does not intervene between buses and traffic signals.
  • Traffic management improvements: Low-cost infrastructure elements that can increase the speed and reliability of bus service include bus turnouts, bus boarding islands, and curb realignments.

Image:Curitiba bus stop.JPG

  • Faster boarding: Conventional on board collection of fares slows the boarding process, particularly when a variety of fares is collected for different destinations and/or classes of passengers. An alternative would be the collection of fares upon entering an enclosed bus station or shelter area prior to bus arrivals (similar to how fares are collected at a kiosk before entering a subway system). This system would allow passengers to board through all doors of a stopped bus. Many BRT systems also use low floor buses (or high level platforms with high floor buses) to speed up passenger boardings and enhance accessibility.
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Arguments in favour of BRT

A BRT system may have a dedicated roadway in areas where traffic congestion is greatest or to bypass mixed traffic to reach the central business district (CBD or "downtown"), but also utilizes existing highways and roadways where traffic is lighter to reduce costs. Optimally, such routes offer advantages over regular bus service with greater service frequency, increased capacity, and higher speed. BRT systems with an exclusively used right-of-way offer the prospect of a more comfortable ride than a normal bus immersed in stop-and-go traffic.

The key argument in favor of BRT systems is that they can provide a quality of service similar to light rail or rapid transit systems, but at greatly reduced capital investment in vehicles and right-of-way. Key to this assumption is the utilization of existing streets, so that capital costs in these areas are only for the vehicles themselves and additional street furniture required for operation. Road maintenance costs are often not attributed to the bus service.

BRT can be faster to implement and more affordable, flexible, and appropriate in scale than light rail for medium capacity requirements or areas that have a moderate degree of density. This can lead to their use as interim systems until light rail is built. Buses also have a great deal of flexibility and can often be rerouted if necessary, such as avoiding blockages for road construction.

The possibility of incremental construction and implementation means that a BRT system can be easily tailored to meet the specific transportation needs and opportunities within individual neighborhoods and transportation corridors.

Busways can offer one seat rides and reduce the number of transfers. For example, a busway system, like the Ottawa Transitway, has many routes using part of the busway to speed trips and save time. Such trips would require one or two transfers on a rail system.

In addition, bus rapid transit is often linked with intelligent transportation systems (ITS), and can involve special buses that control traffic signals, smart card systems, automatic vehicle location, dynamic message signs, and automatically guided buses.

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Arguments against BRT

One bus has space for about 50 passengers only; articulated or double decker buses may push the crush load capacity to about 100. Thus the BRT transport vessel has an intrinsic capacity limitation and finds its place on the capacity scale between standard bus services and rail-based systems. In Europe the bus driver's salary may account for 60-70% of the total operating costs. As one tram driver can drive the same number of passengers as 4-6 bus drivers, on high capacity routes BRT may not be the most cost effective solution.

When a dedicated roadway is only available for part of the bus journey the BRT system is still subject to traffic congestion. As with truck traffic, heavy bus traffic with its high axle-load causes significant wear and tear of the road surface, and regular investment is required to maintain quality. This is a particular problem for guided busways, bus stops and similar situations where the wheels always pass exactly over the same spot.

BRT also suffers from images problems associated with buses (see Perception below). Some argue, they do not attract the ridership of rail lines, and it is not clear whether they can encourage secondary advantages such as neighborhood revitalization and business development. Conversely, some South American systems claim capacity in the order of 40,000 passengers per hour per direction (pphpd), levels that are consistent with some heavy rail, metro systems. Similarly, many more modest BRT systems may operate with daily ridership that equals or exceeds that of light rail (LRT) systems in other cities.

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BRT in metro tunnels

A special issue arises in the use of bus vehicles in metro structures. Since the areas where the demand for an exclusive bus right-of-way is apt to be in dense downtown areas where an above-ground structure may be unacceptable on historic, logistic, or environmental grounds, use of BRT in fully underground tunnels may not be avoidable.

Since buses are almost universally operated by internal combustion engines, bus metros raise ventilation issues similar to those of tunnels. In the case of tunnels, powerful fans typically exchange air through ventilation structures on the surface, but are usually placed in a location as remote as possible from occupied areas to minimize the effects of noise and concentrated pollution.

A straightforward way to deal with this is to use electrical propulsion in tunnels and, in fact, Seattle in its Metro Bus Tunnel and Boston in Phase II of its Silver Line are using this method in their respective BRTs. In the case of Seattle, dual-mode (electric/diesel electric) buses manufactured by Breda were used until 2004, with the center axle driven by electric motors obtaining power from trolley wire in the subway, and with the rear axle driven by a conventional diesel powertrain on freeways and streets. Boston is using a similar approach, after initially using electric trolleybuses to provide service pending delivery of the dual mode vehicles in 2005. In 2004, Seattle replaced its "Transit Tunnel" fleet with diesel-electric hybrid buses, which operate similarly to hybrid cars outside the tunnel and in a low-noise, low-emissions "hush mode" (in which the diesel engine operates but does not exceed idle speed) when underground.

The necessity for providing electric power in these environments brings the capital and maintenance costs of such routes closer to light rail and raises the question of building light rail instead. In Seattle, the downtown transit tunnel was closed in September 2005 for conversion to a shared hybrid-bus and light-rail facility.

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Comparison with other forms of mass transit

BRT attempts to combine the advantages of a metro system (exclusive right-of-way to improve punctuality and frequency) with the advantages of a bus system (low construction and maintenance costs, does not require exclusive right-of-way for entire length).

Compared to standard bus service BRT systems with dedicated right-of-way and thus an increased average transport speed can provide more passenger-miles with the same number of rolling stock and personnel. They also offer the prospect of a more fluent ride than a normal bus immersed in stop-and-go traffic.

Capacity of BRT and normal buses is smaller compared to tram (light rail, tram-train) and rapid transit (metro, mass transit). Typical buses are 12 metres (40 feet) long, articulated buses 18 metres (60 feet). The maximum length for a street-running tram consist (in Germany) is 75 metres (about 250 feet). Metro trains can be 240 m (about 800 feet) long. With similar dwell times in stations the capacity scales with the length.

The typical diesel engine on the bus causes noticeable noise and vibrations. Through the use of electric buses BRT designers hope to increase ride quality and decrease pollution. As the energy use for acceleration is proportional to the vehicle mass, electric traction (with the electricity supplied by wire like in trams and metro) allows lighter vehicles, faster acceleration and energy can be fed back into the grid when the vehicle is decellerating.

In contrast to BRT, both light rail and rapid transit require the placement of rails for the whole line. The tram usually avoids the high additional costs for the engineering structures like tunnels that need to be built for metros. Rail tends to provide a smoother ride and is known to attract significantly higher passenger numbers than road-based systems. An advantage of BRT, however, is that its maintenance facilities can be located anywhere, whereas for rail there must be a facility for each separate line.

Many BRT designers have used the need to construct power conduit systems as an argument against light rail, but a new proposal, known as ultra light rail, would have trams carry their own power, much like a bus, at a significant energy savings due to lack of rolling resistance.

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Controversies

Opponents of bus rapid transit initiatives argue that BRT is not an effective replacement for light rail or subway services. They argue that in order for BRT to have greatest effect, it must have its own right-of-way requiring space and often construction costs. In many cases, BRT does not, and shares the road with cars and other local buses. Buses run on an ordinary road surface, hence it is more difficult for BRT to claim exclusive street use. As a result, BRT operating in mixed traffic is subject to the same congestion, delays, and jarring and swaying rides as do ordinary city buses. Furthermore, signal priority systems, which are often the sole factor differentiating BRT from regular limited-stop bus service (most notably in Los Angeles' extensive "Rapid" system), might cause severe disruptions to traffic flow on major cross streets. Opponents argued that this merely redistributes, rather than reduces, the traffic congestion problems that BRT systems are designed to alleviate. On the other hand, many light rail systems also utilize signal priority system and railroad-style crossing gates to speed up service as well, and in the same time both BRT and light rail get more persons across a road junction than car traffic.

A study [1] of the 98 B-Line BRT in Vancouver, British Columbia, Canada conducted by TransLink, Transport Canada and the IBI Group confirmed many benefits of that BRT system including increased ridership, reduced vehicle emissions, improved reliability, improved customer satisfaction. Analysis of the transit supportive signal timing and the transit signal priority system that supports the service confirmed a slight improvement in travel times and reliability for all vehicles in the corridor with negligible impact to traffic crossing the corridor.

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Implementation in the United States

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Development

Before it even had the name, bus rapid transit first got major backing in the United States with the rise of federal funding for urban mass transportation during the 1960s. The first exclusive busway in the United States was the El Monte Busway, an exclusive bus lane between El Monte and Los Angeles, California. It opened in 1973. Today, American BRT initiatives in receive a great deal of support from the Federal Transit Administration. Planned BRT lines are now eligible to be included in the FTA's New Starts program, which was formerly reserved only for rail projects.

That notwithstanding, the FTA, in announcing its New Starts for 2005, has rated the New Britain-Hartford Busway (Connecticut) "Recommended" but Phase III of the MBTA's Silver Line BRT project (referenced below) "Not Recommended" based on "MBTA's unreasonable operating cost assumptions." This implies that BRT will be subject to the same scrutiny as rail projects, though (also as with rail projects) the FTA will work with the localities to see if projects can be brought into compliance with requirements.

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Perception

BRT suffers from the serious image problem of buses. Quite often buses of any kind are far less attractive to "choice" riders; i.e., riders who could take transit or drive automobiles but prefer transit for certain trips because of perceived amenities of speed, convenience and/or comfort often found in light rail and subway systems. Bus systems suffer not only from poorer speed and ride quality, but from the perception of buses as a social accommodation — a means of transportation used by those who have no other choice, called "transit dependent."

In the view of some, advocacy for buses among the lower classes contributes to the socioeconomic unattractiveness of BRT. For example, in California, a 1996 lawsuit by the Los Angeles-based Bus Riders Union (site), and litigation initated in 2005 by related groups in the Bay Area, have sought to force transit agencies to shift funds from rail and BRT construction to mixed-traffic bus projects.

While many BRT systems utilize state-of-the-art buses that differ substantially from traditional buses, light rail systems are perceived of still having a higher travel quality. Some put it bluntly as "a bus is still a bus". Routes that have been converted from BRT to light rail have often seen very large ridership gains.

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Implementation in South America

Curitiba's pioneering BRT system (which influenced the construction of the Metro Orange Line BRT in Los Angeles) has seen ridership fall since the mid-1990s as its city's middle class has burgeoned, with cars more readily available resulting in increases in traffic congestion. An extensive summary of information regarding the Curitiba busway system is available at [2] São Paulo, mindful of how traffic has choked commerce in the city, has begun construction of a subway system to complement bus services.

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Implementation in Europe

There is a large number of public transport systems in European towns that fulfill several of the BRT criteria given above, however, they are rarely designated as BRT. Bus lanes and exclusive use of key city-centre streets is commonplace, bus priority on approach to traffic lights is quite frequent. All-door boarding is standard during daytime, ticket machines can often be found at bus stops, sometimes in the buses, ticket booklets pre-purchased with the passenger validating the individual ticket at time of boarding, and the use of travel passes is actively encouraged. Particular at rush-hour there are spot checks only.

Dedicated engineering structures for bus-only use are less frequent. If capacity demand is high enough to warrant these, there usually is also a case for the construction of a tram or light rail line, thus bus-only systems are more frequently found in small to medium-sized towns. In larger towns and cities it is not rare at all that a right of way exclusive to public transport is used by both tram and bus.

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List of Bus Rapid Transit Systems

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BRT systems in North America

The Table of Bus Rapid Transit Systems in North America holds more comprehensive information.

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Canada

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Mexico

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United States

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BRT systems in South America

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BRT systems in Asia

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BRT systems in Australasia/Oceania

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BRT systems in Europe

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See also

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External links

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Critical of BRT

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From lightrailnow.org

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From other sources

nl:Hoogwaardig openbaar vervoer ja:ガイドウェイバス fi:Bussimetro zh:巴士快速交通系统

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