Land-vehicle Design
Motorised 3-Wheelers
Motorised 3-wheelers are commonly produced industrially for cheap and traffic-efficient transportation (cargo and to a lesser extent passenger taxis).
This is a recent class of land-vehicles and only a few designs exist.
Tricycles
Tricycles, are very cheap to protoype. A handful of companies design and produce several such designs at very small scale.
In recent years, DC-motor powered cargo-trailers have also been designed
as bicycle add-ons, and have operational characteristics similar
to tricycles.