Bus Rapid Transit - Comparison With Other Modes
High-end bus rapid transit's main advantage over comparable modes like light rail and metro rail are its routing flexibility and cost (and implementation speed) advantages.
BRT allows for far more routing flexibility than rail because of buses' fundamental nature. Unlike trains, buses can jump on and off their "tracks" (busways), thus combining feeder and line-haul functions in one vehicle. For example, a bus can pick up suburban commuters in their neighborhoods, enter a busway leading into an urban downtown, then leave the busway and circulate on downtown streets. This trip would otherwise require two transfers (suburban commuters driving or taking a feeder bus to a suburban rail station, traveling to the downtown, then transferring to a city bus, metro rail system, or taxi).
Furthermore, BRT can generally be constructed at less cost than rail systems. A survey by the U.S. General Accounting Office (PDF) found average capital costs of $7-55 million per mile for BRT systems using busways compared to $12.4-118.8 million per mile for light rail.
[Graph from U.S. GAO, "Bus Rapid Transit Shows Promise," Sept. 2001]
Compared to rail, BRT may have to face the problem of image. In some communities, buses are viewed negatively as dirty, slow, or only for people without other transportation options (depending on the quality of existing bus service, these perceptions may be justified). In these places, "selling" BRT may require a branding campaign which clearly separates BRT from traditional bus service. Of course, in the long run it is a BRT system's quality of service which will separate it from regular bus service.
BRT's other disadvantage is that it has less carrying capacity than metro and commuter rail; it has comparable capacity to light rail. Whether higher-capacity modes can be cost-justified depends on the land use patterns of a given area. In suburban areas like the Hudson Valley, ridership on a flexible BRT system will likely be higher than on a fixed-route light or commuter rail system, even if commuter rail can theoretically carry more passengers.
The largest articulated BRT buses still carry fewer passengers than individual light and heavy rail trains, so to provide the same amount of service as a rail system, a BRT system may have higher labor needs but provide more frequent service. For example, a light rail system may run a 500-passenger train every 10 minutes, while a BRT system may run a 200-passenger bus every four minutes to provide the same amount of service.
Lower-end BRT using on-street bus lanes and/or signal priority should be considered as a replacement for (and an upgrade from) high-volume regular bus routes. The advantages are self-evident: faster travel and increased ridership. BRT conversions may face political opposition if a parking or traffic lane is taken for buses, so planners should ensure that a BRT conversion will indeed result in noticable improvements.
Energy Efficiency
While some critics have argued that bus rapid transit is less energy efficient than rail transit, the available evidence is mixed. A study of German cities estimated that bus transit was 4 times as energy efficient as car travel, while light and metro rail was 2.5 times as efficient as car travel (per passenger-kilometer). By contrast, a U.S. study found that the average train trip was 8.4% more efficient than the average bus trip, and 16.3% more efficient than the average automobile trip. (Both studies are cited in R. Cervero's The Transit Metropolis.)
The large discrepancies in existing studies may exist because transit energy efficiency depends on many variables, including the level of congestion in an area, how heavily used a transit system is, and the differences between various bus and train models. For example, a significant portion of New York City's public bus fleet is diesel-electric hybrid. Because both rail and bus transit are more fuel-efficient than cars, the relevant question is not which mode is theoretically more efficient but which mode or combination of modes will best divert automobile users to transit.
<< Previous Section: BRT = Rights-of-Way, Faster Boarding
Next Section: Suburban Implementations >>
