Difference between revisions of "Bus rapid transit"
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Revision as of 19:29, 11 April 2012
In corridors with high travel demand, bus rapid transit lines 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.
The Federal Transit administration identifies several features, the presence of which determines the type and quality of a BRT system. They include: bus lanes, busways, fare collection, automatic vehicle location, land use, signal priority, stops, shelters, vehicles design, and expressways (Diaz 2009).
Depending on the community’s needs, a BRT service might be 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 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 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.
Bus-only lanes on congested corridors or at choke-points in the road network provide buses with considerable operation benefits and a potential competitive advantage vis-à-vis private automobiles. In particular, bus-only lanes increase transit vehicle reliability by reducing conflicts with other vehicles in mixed traffic that might otherwise delay transit vehicles.
Reducing conflicts with other vehicles should increase schedule reliability and help transit agencies adhere to scheduled headways. Furthermore, bus-only lanes can allow buses to pass uninhibited by traffic through congested areas, improving overall speeds. When buses can make their runs in less time, agencies can maintain the same level of capacity and service using fewer buses, allowing them to save on operating and capital costs.
In many instances, bus lanes can be installed with a minimum of 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.
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 provide even greater operational advantages over bus-only lanes by reducing interactions with other vehicles entirely, except in instances where the busway may intersect streets (although this can be alleviated with transit signal priority). Furthermore, busways may allow for easier boarding and alighting at the bus stations, thanks to stations that allow for more level boarding.
Automatic vehicle location
Stops & shelters
The more suburban city of San Bernardino is investing in a BRT line. Dubbed SBX, the line will connect Cal State San Bernardino with the city center.
Diaz, Roderick. Federal Transit Administration, "Characteristics of Bus Rapid Transit for Decision-Making." Last modified 2009. Accessed November 3, 2011. http://www.fta.dot.gov/documents/CBRT_2009_Update.pdf.