I'll pull together a response to feedback on the controversial Brisbane busway post in the next few days, but meanwhile, Engineer Scotty asks a good clarifying question:
Part of the problem with BRT [Bus Rapid Transit] acceptance in the US, is [that] most visible BRT systems ... tend to look and act like rail-based metros. In the US, we speak of BRT lines--the Silver Line in Boston, the Orange Line in LA, EmX in Eugene, OR--and so forth. The busses which run on BRT are different than the local busses (different branding, different route nomenclature, different fare structures, rapid boarding, longer station spacing, nicer stations, proof-of-payment or turnstiles rather than pay-the-driver-as-you-board)--
Everything about the service is made to look like a rail-based metro service, except for the tires. I think that therein lies the problem--trains are better than busses at being trains, and this sort of distinct corridor service tends to be better served by rail, all else being equal.
There are exceptions, of course--low volume small-city lines like EmX again--but such services ignore the fundamental strength of busses, which is that they aren't tied to the physical infrastructure. Other than the capital cost--something which it is usually not wise to optimize for, as governments can generally get capital funding more easily than operating revenue--if you limit the BRT vehicles to the BRT infrastructure, you're generally getting something that costs more and not less to operate. BRT, to be most useful, needs to be disconnected from the notion of "lines", where the line refers to the physical infrastructure. Would you agree with this, or am I barking up the wrong tree?
Scotty is onto an important distinction. In the BRT business, the systems Scotty cites (Eugene, Los Angeles Orange Line, Boston Silver Line) are
called 'closed' systems, in that all buses operate only within the
specified infrastructure, with a separate brand. Each is just one route or in a few cases, like the Silver Line, there may be two or three patterns.
Brisbane is an 'open' system, like Ottawa and Pittsburgh, and like the El Monte Transitway in Los Angeles. The busway infrastructure is branded, and there are bus routes that remain entirely within it, but there are many others that branch off of it into the regular street network. The Busway brand applies to the infrastructure, not the routes. The buses running in the busway are ordinary Brisbane Transport buses like you'd see on any route in the city.
However, the distinction between open and closed is not the same as the distinction between "emulating light rail" and "emulating heavy rail." That distinction is about grade separation, i.e. separation from cross traffic. Typical recent American applications such as the Los Angeles Orange Line or Eugene's EmX are emulating light rail in their ability to run onstreet and cross streets at signals, which heavy rail generally doesn't do. As I've said, I think Brisbane's busway segment is a fairer imitation of heavy-rail speed and reliability than anything in North America, apart from fragmentary busways in Ottawa, Pittsburgh, Los Angeles etc. Of those, only Ottawa's is anything close to a complete system, and it's compromised, of course, by the lack of a downtown segment.The two distinctions are quite separate. Here in Sydney, for example, there are two busways (Liverpool Parramatta T-way and North West T-way) that are entirely at grade with lots of signalised intersections. The first is currently 'closed' -- operated by a single line running the whole length -- but there are plans to make it 'open.' The second has always been open, i.e. served by a range of routes that branch off of it at various points.