Bus rapid transit

Introduction

In corridors with high travel demand, Bus Rapid Transit lines (BRT) can help move people quickly and provide a viable alternative to the private automobile. Typically, BRT lines are distinguished from baseline bus service by their speed, frequency, capacity, and reliability. BRT service also offers many advantages of light rail, such as high speeds and a strong identity, for lower implementation and construction costs. The Transportation Cooperative Research Program (TCRP) defines Bus Rapid Transit as “a flexible, rubber-tired form of rapid transit that combines stations, vehicles, services, running ways, and ITS (Intelligent Transportation Systems) elements into an integrated system with a strong image and identity.

Depending on the community’s needs, a BRT service could take the form of an upgraded conventional bus line that features frequent all-day service and improved bus stops with real-time arrival displays. Corridors with heavier travel demands may justify a greater capital investment in BRT.

While full BRT is often viewed as less expensive to construct than rail, there are important tradeoffs to consider within the wide spectrum of BRT systems. A BRT line with its own dedicated right-of-way, grade separated intersections and transit stations would provide very fast and reliable “rail lite” service, but could easily cost hundreds of millions of dollars. Operational improvements which speed buses can also reduce the cost of offering service by reducing the time that it takes to complete a route. This means that drivers can complete more routes in a day and a transit agency can maintain set headways with fewer buses than in slower operations. When funding is limited, the benefits of adding these expensive features to one line should be weighed against implementing less expensive measures – i.e. bus-only lanes, upgraded shelters, signal priority – on a greater number of lines. The question may ultimately come down to which alternative saves the most time per dollar invested. Agencies may, however, want to consider other factors as well, such as mobility improvements, social impacts, and land use effects of new fixed route transit service.

Features

Running Ways

BRT systems may use a wide variety of running ways, which have a major impact on the overall system performance. Bus-only lanes on congested corridors or at choke-points in the road network provide buses with operational benefits and a potential competitive advantage vis-à-vis private automobiles. Running ways may be complemented by other treatments that improve travel time listed below, such as transit signal priority, queue jumps, and bypass lanes.

Busways

The Los Angeles County Metro Orange Line carries over 20,000 trips every day, traversing the San Fernando Valley. Photo via the Metro Transportation Library and Archive.

In corridors with high existing or potential transit ridership, transit agencies may want to consider investing in a segregated busway. This is particularly relevant where the agency owns an existing right-of-way or if there is excess road space. Busways grant exclusive use of the right-of-way to buses. They may be grade-separated, at-grade, or median lanes. Busways that are separate from general traffic flow improve reliability and travel time, but are generally more expensive to implement. Busways provide even greater operational advantages over bus-only lanes by reducing interactions with other vehicles entirely, except in instances where the busway intersects with streets. Busways also increase driver productivity, increase fuel efficiency, and improve safety. Furthermore, busways may allow for easier boarding and alighting at the bus stations because they allow for the space to provide raised platforms.

Bus lanes

Bus lanes also provide advantages for operating BRT service. If contraflow lanes are used, they should operate at all hours, while concurrent flow lanes may be used during peak hours only. Bus lanes are useful for enhancing the identity of the service. Several criteria determine the success of bus lanes: they should carry a high frequency of buses in a congested area, the street right-of-way should be able to accommodate them, and the community should be supportive.

Reducing conflicts with other vehicles and allowing transit vehicles to circumvent congestion improves overall speeds and increases schedule reliability and help transit agencies adhere to scheduled headways. When overall speeds are improved, buses can make their runs in less time. This allows agencies to maintain capacity and service using fewer buses, allowing them to save on operating and capital costs.

Bus lanes have the advantage of being easy to implement quickly and generally do not require the higher costs of property acquisition and construction that are associated with busways. In many instances, bus lanes can be installed with minimal capital expense -- just what is needed to re-stripe a street. Thus, bus lanes can be deployed in corridors that might not otherwise warrant a more extensive capital investment in service quality.

Transit Signal Priority (TSP)

Transit signal priority (TSP) alters signal timing to better accommodate transit vehicles, but does not necessarily preempt regular signal timing. Rather, it may extend a green light or shorten a red light to minimize dwell time. TSP is a flexible and common tool for BRT systems and can be applied along an entire arterial system or at individual intersections.

Queue Jumps and Bypass Lanes

Alternatives to TSP include queue jumps and bypass lanes, which both require a right-turn or additional right lane. Queue jumps utilize a special bus signal, separate from the signal phases for general traffic, that gives buses an early green light to allow it to merge into the adjacent through lane. This early signal is typically only a few seconds long. Bypass lanes make it possible for buses to cross an intersection to a stop on the far side before merging back into general traffic.

Service Characteristics

Regardless of the type of running way used, BRT service also benefits from spacing stops a greater distance apart than typical local stops or allowing express bus service to skip some stops. This allows BRT buses to achieve higher average speeds than local bus service. In fact, the Federal Transit Administration recommends spacing BRT stops similar to how a light rail system might space its stops. In the Los Angeles region, for example, average stop spacing of the two BRT lines is nearly one mile. Ultimately, though, stops must be spaced so that they serve trip generators and the service is able to maintain high overall speeds where appropriate.

Frequent service is a keystone of Bus Rapid Transit service. Typically, BRT service should run more frequently than adjacent local service because it is considered to be a higher order of service. The American Public Transportation Association recommends that BRT serve enough destinations to justify running buses at headways of at least every ten minutes. Frequent service, paired with service that lasts the full day, has traditionally proven to be convenient for passengers and a successful strategy for introducing new BRT service. The federal New Starts and Small Starts grant programs have certain requirements for the frequency and hours per day that corridor bus projects must run in order to qualify for funding, as well.

Fare Collection

Some BRT systems use off-board fare collection because of the time savings it can offer, which translates into greater reliability for passengers. However, the cost effectiveness of this strategy may be limited if many passengers use pre-paid smart cards or if the cost of installing ticket machines and hiring staff to inspect for proof of fare payment outweigh the benefits.

Stops and Stations

BRT stations contribute to the identity and image of the line while providing valuable amenities and services. BRT stations have been estimated to account for up to 15 percent of ridership increases. However, the stations’ size, design, and amenities offered are all largely based on the needs of the service provider and BRT stations may range from basic platforms to large intermodal transit stations. A BRT line may count a variety of station and stop types along its route, depending on the needs and volume of passengers expected to board at each stop. The American Public Transportation Association does not recommend using basic bus stops for BRT lines, though, because they do not distinguish the line from local bus service. For an example of an upgraded stop design, see the photo of the Los Angeles Metro Orange Line’s BRT stop.

A Los Angeles Metro Orange Line bus picks passengers up at one of its shaded stops. Photo by Gary Leonard courtesy of Los Angeles Metro. Originally published on The Source, thesource.metro.net/

Additional Reading

Gray, George, Norman Kelley, and Tom Larwin. Mineta Transportation Institute. “Bus Rapid Transit: A Handbook for Partners.” 2006.

This guide, created by the Mineta Transportation Institute at San Jose State University, was co-sponsored by the California Department of Transportation (Caltrans) and the United States Department of Transportation. It describes the role that Caltrans plays in working with local transit systems to create BRT systems, as well as how those BRT systems should interact with the state highway system. The guide also offers lessons learned from around the state and a brief description of the BRT systems in California at the time of publication in 2006.

The Transit Cooperative Research Program. "Report 118: Bus Rapid Transit Practitioner's Guide." 2006.

This guide was created in order to guide practitioners in planning and implementing BRT service and includes methods for estimating ridership, costs and benefits, and assessing land development effects of BRT service. It offers descriptions of existing BRT services in North America and around the world.

The American Public Transportation Association Standards Development Program. "APTA Manual of Standards and Recommended Practices for Bus Transit Systems." 2010.

The American Public Transportation Association has developed a comprehensive set of recommended practices for operators of bus transit service. This includes guides on the branding, operation, and design of BRT systems and facilities. This link also includes recommendations for using intelligent transportation systems for BRT service.

The National Bus Rapid Transit Institute. NBRTI.org.

The National Bus Rapid Transit Institute offers a wealth of resources for advocates of BRT. They publish a quarterly newsletter and maintain a database of currently operating BRT systems, maintain a listserve, and have published evaluations of several BRT systems.