Although a 'standard cycle' is sometimes proposed, there is too much variation
in both geometry and dimensions, for a single vehicle to represent all
particularly with regard to steering. [IAN 195/16 - Figure]
A straight route with a 1.5 m gap allows all of these vehicles to pass through.

The vehicles considered here are based on a larger collection at:
List of Land Vehicles Types by Number of Wheels - [wikipedia]

This is a smaller collection because:
- all the vehicles here are wheeled;
- vehicles that steer similarly form a single category;
- the emphasis is non-motorised vehicles (10 mph / 16 km/h).

One Wheel
Two Wheels
Three Wheels
Four Wheels