Quote:
Originally Posted by allan_kuan
Is it just me or are a lot of people now just resigned to the fate of having BRT plow our busy streets for many more years to come? (sigh)
(optimism sputters to a stop)
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Not necessarily, but it is still difficult to envision a skytrain extension up to UBC, so even up to Arbutus, you will still have the capacity issue west of arbutus (and probably further exacerbated, by the fact that other currently competitive alternative from Expo line, like 43 will be not really anymore.
On the topic of bi-articulated bus, I have plan to write something on it for my blog,
but here some preliminary bits:
From number I have collected from the
lacmta which has a fleet including 40", 45", 60" and 65 foot buses, and other correlations, you can deduce that the bus capacity as function of its length is looking like it:
I have purposely put an index capacity normalized at 1 for the staple 40 foot bus, rather an absolute pax capacity, since you can get great variance for it across agencies:
For example LACMTA estimates capacity of its 65 footer at 100 pax, the constructor, nabi, will come up with number at 71, while in Bratislava, similar bus length will be considered able to carry 200 pax, and bi-articulated bus are more often than not in area having generous standard for bus capacity closer to the one of Bratislava than the one of LA
That said you could question, the form of the curve:
There is lot of "dead" space in a bus, bus driver space, wheel's room...which will impair its capacity as well as the configuration of all of it can make the circulation, hence optimal loading and dwelling time more or less efficient (usually a bus carries less pax per sq meter rear of its rear wheel, rather than front of it, mostly because door access become more complicate (on the topic see
http://voony.wordpress.com/2010/02/0...-hydrogen-bus/ )
the articulation area is kind of a dead space of its own too, and it is usually 5 feet long...
(I don't know how to make image same scale), but the pictures below illustrate enough why a 65 foot bus, though only 10% longer than a 60 foot, can carry 20% more passenger (lacmta number)
artic 60 foot
Nabi 65 foot bus in LA
Citaro GL 65 foot bus
the additional articulation and wheel room is why a 80 foot bi-articulated bus doesn't provide much more capacity than an 65 foot single articulation...and eventually it is on of the reason why 65 foot seems to become overly popular (i guess it involve lot less maintenance too)...
Another reason from a Vancouver viewpoint, to prefer the 65 foot is that basically the market for 80 foot is nonexistent in NA (so as previously mentioned could require a custom order, or import with all associated risk), what is less the case for 65 foot, which being more versatile could be also deployed on much more route, so a 65 foot procurement could nourish more interest from manufacturer (and from a manufacturer view point, the work is mostly body extension in the case of the Nabi, Citaro has been one step further, but in a more established market).