We need a better bus

We need a better bus. A bus that fits better on the road, and a bus that fits passengers better.

Vehicles with a long wheel-base will sweep sideways in a turn because the rear wheels do not follow the front wheels:

Off-tracking is another name for that side sweep.

Every urban dweller knows that unpleasant feeling when long vehicles sweep inwards toward your toes while you are theoretically safe on the sidewalk. That unpleasantness is enhanced because you know that the driver cannot directly see that inward sweep, it is after all well behind the driver’s front view, so it is up to you to protect your toes and get out of the way.

To limit that inward sweep, bus designers shorten the wheel bases by moving the rear wheels in and the front wheels back, giving us the distinct city bus look:

But we as we know, this does not completely solve the inward sweep problem, and it introduces another problem. The outward sweep of the front and rear of the bus:

A shorter wheel-based bus sweeps in at the centre and out at both ends.

The street design guides acknowledge the large turning radii of city buses:

Not only does this not make for an unpleasant experience for those on the sidewalk, it also slows the buses down. Since they do not fit in one lane around a corner, they have to wait for the opportunity to take up two lanes. As I heard a bus driver once say, “a bus can either turn from one lane into two or two lanes into one”.

The solution is a bus with a significantly shorter wheelbase by introducing an articulation into the standard sized bus and two articulations where we currently have one. With multiple articulations, the bus could take the turn like a centipede instead of like a board. A standard 12m or 40′ bus would have one articulation and an articulated 18m or 60′ bus would have two articulations. The double articulated buses would have to have a second set of steerable wheels to keep all of the wheels in a single track, but that is current technology and is already seen on some other multiply-articulated buses. There is also nothing stopping double-decker buses from being articulated or multiply-articulated in a fairly flat city.

With a shortened first segment, a bus like this would be more city friendly.

The second major improvement to the bus would be to make it fit passengers better. The introduction of low floor buses is a great help to boarding and to wheelchairs, but lowering the floor has made the wheel wells much more of an obstruction:

These are the wheel wells for the front wheels.
And these are the same wheel wells looking forward.

On a low floor bus, the wheel wells are mostly unusable except for bag storage. They are also a major congestion point when people decide that the narrowing is is a good place to stop.

The rear wheel wells can still be fit under side benches because they are mostly subsumed under the higher floor:

The rear wheel wells fit under side bench seating in the high floor rear of the bus.

Other bus designs have tried to utilize the wheel well space by putting raised pedestals over the wheel wells with seats on top, but the pedestals still make for narrow aisles and less standing area:

But buses don’t actually need large wheels and tires. It is possible for a bus to have smaller wheels as long as they can handle the load. To do this, smaller wheels must have higher pressure tires, non-pneumatic solid tires, or more wheels, which would be arranged in tandem.

Non-pneumatic tires can have high loading, and the ride is improving, but I’m not sure whether the technology is quite ready for city buses:

These are mostly for heavy industrial equipment that doesn’t go that fast.

Higher pressure means more expensive tires and more dangerous blowouts, so it is probably most practical to have more wheels arranged in tandem like this early bus:

Current low floor buses have large wheels and large wheel wells:

The dark handlebar shape is intending to show the steering gear and drive train on a low floor bus which is actually much more complicated:

But if much smaller wheels in tandem were used, the wheel wells would fit under bench seating and would not create any narrow, constraining aisles:

Small wheels only require small wheel wells.
And small wheels in tandem allow for a wider aisle and standing area.

Both of the front steering wheels need to steer, but this is already done when tandem wheels are used as seen in the old bus:

I am also assuming an all electric bus, so that complicated drive train can be simplified by using in-hub electric motors:

With in-hub electric motors, there’s no drive shaft but only electric cables which makes it possible to power all of the wheels without a cat’s cradle of drive shafts.

With smaller wheel wells, the interior of a tandem wheeled bus should look more like the interior of a modern low floor tram:

The smaller wheel wells are located under these chairs, but they create a narrower aisle than they would on a bus because of the 1435mm rail gauge.
The 1435mm rail gauge that would not be a factor in a 2500mm wide bus.

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