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Bus rapid transit

From Academic Kids

Bus rapid transit (BRT) is a relatively new umbrella term for urban mass transportation services utilizing buses to perform premium services on existing roadways or dedicated rights-of-way.

BRT encompasses a broad variety of modes, including those known or formerly known as express buses, limited busways and rapid busways. What is now called bus rapid transit first got major impetus in the US with the rise of federal funding for urban mass transportation during the 1960s. Bus rapid transit targets the same segment of the transit market as light rail transit. Proponents say it combines the rapidity of a rapid transit or light rail line with the flexibility of buses.

Contents

Introduction

The Bus Rapid Transit (BRT) system is based on the concept of utilizing various features of light rail and rapid transit to speed up services provided by buses. A BRT system may have a dedicated rights-of-way (as in rapid transit) in areas where competition with highway traffic would be greatest, but also utilizes existing highways and roadways in less-congested areas wherever possible to reduce costs. For example, existing bus routes could operate normally in most areas, but would enter a special lane on an existing highway, or a dedicated right-of-way to bypass mixed traffic to reach the Central Business District (CBD).

The key argument in favor of BRT systems is that they provide a higher quality of service (similar to light-rail transit systems), but at greatly reduced capital investment in vehicles and right-of-way, facilitating their use as interim systems until light rail is built. 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. Proponents say that BRT is faster to implement and more affordable, flexible, and appropriate in scale than light rail for medium-sized areas, or areas that have a moderate degree of density. Proponents also say that it allows for incremental construction and implementation and can be easily tailored to meet the specific transportation needs and opportunities within individual neighborhoods and transportation corridors. Opponents argue that bus rapid transit services are simply improved bus lines that do not attract the ridership of rail lines, or encourage secondary advantages such as neighborhood revitalization and business development.

Insofar as BRT can utilize dedicated rights-of-way it offers advantages over regular bus service, including service frequency, increased capacity, and speed.

The bus rapid transit initiative has received a great deal of support from the Federal Transit Administration in the United States. A new development encouraging BRT is that it is now eligible to be included in the FTA's "New Starts" program formerly reserved for rail projects only. 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.

BRT: A Definition

BRT is a broad term given to a variety of different transportation solutions that operate through the usage of buses. It can come in a variety of different forms, from dedicated busways that have their own rights-of-way (e.g., Ottawa's Transitway) to bus services that utilize HOV lanes and dedicated freeway lanes (e.g., Honolulu's CityExpress) to limited stop buses on conventional routes. 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, AVL bus tracking, dynamic message signs, and automatically guided buses.

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

  • Bus lanes: A lane on an urban arterial or city street is reserved for the exclusive or near-exclusive use of buses.
  • 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 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.
Bus stop in Curitiba
Enlarge
Bus stop in Curitiba
  • 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.

BRT in subways

A special issue arises in the use of bus vehicles in subway 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, visual, or environmental grounds, use of BRT in fully underground subways may not be avoidable.

Since buses in the U.S. and many other countries are almost universally operated by fossil fuels, bus subways 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 downtown subway 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 were used until 2004, obtaining power from trolley wire in the subway, and powering their electric motors by diesel generation when outdoors. Boston plans to do the same, but for the time being is using electric trolley buses to provide service. In 2004, Seattle replaced its "Transit Tunnel" fleet with diesel-electric hybrid buses, which operate similarly to hybrid cars outside the tunnel and exclusively under electric battery power 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 bus subway is to be closed in the autumn of 2005 for conversion to a shared electric-bus light-rail subway.

Controversies associated with BRT

Operational Factors

Opponents of bus rapid transit initiatives argue that BRT is not an effective replacement for light rail or subway services. They argued that in order for BRT to have greatest effect, it must have its own right-of-way; in many cases, BRT does not, and share the road with cars and other local buses. 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.

Perceptions

BRT also suffers from a serious image problem. In many places (and particularly in the United States), buses of any kind are far less attractive to middle- and upper-class riders than light rail and subway systems, suffering from resultingly low ridership among segments of the population that prefer travel by automobile to using any sort of public transportation whatsoever. (The fact that the overwhelming majority of bus riders in many U.S. cities is composed of blacks and Latinos serves as a further deterrent to bus ridership by middle-class whites.) While many BRT systems utilize state-of-the-art buses that differ substantially from traditional buses, BRT opponents insist that "a bus is still a bus." Routes that have been converted from BRT to light rail have often seen very large ridership gains. Even Curitiba's pioneering BRT system has seen ridership fall since the mid-1990s as its city's middle class has burgeoned, with resulting increases in traffic congestion. Mindful of how traffic has choked commerce in São Paulo, the city has begun construction of a subway system. In the view of some, advocacy for BRT 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, and litigation initated in 2005 by related groups in the Bay Area, have sought to force transit agencies to shift funds from rail and highway construction to BRT projects.

BRTs in North America

Dedicated right-of-way
Exclusive highway lanes
Exclusive on-street lane
No exclusive lanes but heavy intersection bypass lanes
and limited stops and/or traffic light priority
Part-time exclusive lanes on some lines, limited stops, traffic light priority
Conventional bus lines with limited stops

Bus rapid transit systems outside of North America

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