like a bicycle does - the single front wheel turns, as the driver turns the handle bars, the two rear wheels stay aligned and front facing.

How does a cycle-rickshaw turn without a differential? This answer applies to a rickshaw with two wheels on the back, which are connected by a fixed axle. On the front, is one wheel which is used for steering. When a car’s engine turns the back wheels through a differential, only one wheel is being driven at any given time. This is necessary because, when turning a corner, the outside wheel takes a larger diameter curve than the inside wheel. If both wheels turned at the same speed, as without a differential, the inside wheel would spin on the road and not grip. I once bought a car that had been used for racing. The differential had been welded to prevent normal functioning. On straights, the car really accelerated well because the engine transmitted its power equally to both wheels. But on corners, one of the back tires would scream – even at low speeds. A rickshaw, without a differential would act similarly to a car with a welded transmission. The big difference is that a car’s engine has much more power than a human rickshaw driver. A human would never have the power to squeal a bike’s back wheel. When a car with a welded differential squeals a tire, this represents a waste of energy since the power is not fully being transmitted to effective speed. When a bike rickshaw turns a corner, the waste of energy would be felt by the rickshaw driver as greater resistance as the two back wheels would be turning on different circumferences. One of the tires would be skidding causing friction, a loss of energy and more demand on the peddling driver. The inefficiency of the rickshaw described above, could be eliminated by having the bike chain drive only one wheel. All other wheels, whatever their position on the rickshaw, must be independently free-wheeling. In the Philippines, such rickshaws exist and they are basically a normal bike with a sidecar attached. I’ve seen other rickshaws in other Asian countries where there are two wheels on the front where the passengers sit. The seat and wheels are one assembly which turns together, and the front wheels are one their own independent axles. There is one back wheel which is driven by the chain.