BRT: long haul service in the US versus comprising a "transit network" in South America
There are the factors that are considered the primary elements of quality bus rapid transit service (From TCRP report 90, Bus Rapid Transit, volume 2, Implementation Guidelines although this AC Transit webpage does a nice job illustrating the points as well:
A. Running Ways – including mixed traffic lanes, curb bus lanes, and median busways on city streets; reserved lanes on freeways; and bus-only roads, tunnels, and bridges.
B. Stations – Providing higher quality infrastructure than simple bus stops. This can include platforms, more significant forms of shelter, quality information systems and other amenities.
C. Vehicles – BRT vehicles can include conventional standard and articulated diesel buses however there is also a trend toward innovations in vehicle design. These include (1) "clean" vehicles; (2) dual-mode (diesel-electric) operations through tunnels; (3) low-floor buses; (4) more doors and wider doors; and (5) use of distinctive, dedicated BRT vehicles for image and branding.
D. Intelligent Transport Systems – Use of technologies including automatic vehicle location systems; passenger information systems; transit preferential treatment systems at signalized intersections, controlled tunnel or bridge approaches, toll plazas, and freeway ramps.
E. Service Patterns – Usually with high service levels and can include a mix of express and stopping patterns. Significantly, most networks operate beyond the running ways and onto local streets which can reduce the need to transfer at stations.
While looking into it further I came across the large body of transit research by Monash University professor Graham Currie, who has written a great deal about bus rapid transit, among other topics.
One of the papers, "Understanding ridership drivers for bus rapid transit systems in Australia," compares four different bus and bus rapid transit services in Australia in an attempt to figure out what are the most salient characteristics that drive ridership.
I have criticized some of the hype or cheerleading about bus rapid transit in the US, because it is made from a faulty comparison, in that in the successful bus rapid transit networks in cities like Curitiba and Bogota, which have more than one million daily riders, the riders are transit dependent and more willing to withstand "crush densities" (maximum number of riders on the bus) more than double than is typical in the US.
But reading the Currie paper made me realize another difference. BRT is promoted by organizations like the ITDP and the World Resources Institute as being superior--not just cheaper--than rail transit.
While I don't know if bus is superior to rail in cities like Bogota or Curitiba, there is no question that it works. But, the reality is that bus rapid transit systems in those cities are true networks.
For example, the Transmilenio system in Bogota has 12 lines, serving a dense core of about 35 miles in length and 136 stations, with 12 more stations under construction, serving 2.2 million daily riders (a couple years ago there were riots because of the failure to expand the system, which is overcrowded).
The Curitiba system is set up more like a subway system, with fewer lines (6) and stations (21), and a system length of about 50 miles and serves 2.3 million daily riders (by contrast the DC area subway system has 6 lines, 91 stations, 117 miles of track and about 760,000 daily riders).
Comparatively, while BRT in the US might be part of a transit network, mostly as delivered it is is mostly a long haul line or two, which may substitute for a single light rail line, but isn't a true network. Also see "Why bus rapid transit has stalled in the Bay Area," from the San Francisco Chronicle.
And that's fine. But it's important not to generalize the impact of true BRT in South America to how it is used in far more limited implementations in the US.
The line is 6.8 miles long, serving 59 stations, and the ridership is not usually reported in hard numbers only percentage of growth over previously existing service, because at the root, the number is low, fewer than 15,000 riders per day.
Note that BRT lines in Los Angeles have significantly higher ridership, but under 50,000 daily riders.