Conventional buses have a floor at a height above the axles of
the bus, with some wheel well intrusion which is hidden
underneath seating. Typically three steps are required to get
from curb level to bus floor level. Climbing steps slows boarding
for most and makes boarding impossible for some. Slower boarding
means a slower trip, which affects everyone.
One solution to the accessibility problem of buses is the use
of wheelchair lifts installed at the front entrance of the bus.
The problem with this solution is that it can take two minutes or
more to load a wheelchair bound passenger, and of course it does
nothing to speed boarding for those who can climb steps but find
it difficult. As well, the lifts themselves must survive a
hostile vibration-filled environment.
Another alternative, which is currently becoming popular, is
to provide a low floor from the front entrance to the back
entrance, with steps to a higher floor area just aft of the back
entrance, giving space for the rear axle, engine and drivetrain.
In the case of some articulated trolleybuses (and dual-mode buses
which use small diesel engines as generators), the low floor
extends most of the way or all the way back, since the electric
motors are small enough to be placed under the seats.
There is a problem with wheel well intrusion in such designs,
however - due to the large wheels required on rubber tired
vehicles, the interior space taken up by the wheel well is too
high to place seating on, and thus the space is just a shelf,
which is usually "wasted space" - in any event, it
cannot be used for seated or standing passengers. Low floor light
rail vehicles do not have this problem, since there are more,
smaller wheels.
The reduced person carrying capacity of low floor buses can be
an issue if they are used on busy routes, since it may be
necessary to run more buses to provide an adequate level of
service.
What's out there today?
New Flyer low floor standard length
(40 foot) buses have been in service in Victoria since 1992.
There are now 57 of them. There is an order outstanding for 91 of
these buses for Vancouver, and 17 for West Vancouver. New Flyer
low floor buses have a fold out ramp, and steps to a high floor
area behind the rear door.
(This section should have information on other low floor
designs in use elsewhere but the author doesn't currently have
such information - except for a few dual mode buses to be found
on the trolleybus page.)
James Strickland
|