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