A steel-tube chassis attaches to the bicycle's rear-wheel hub. This chassis rests on a narrow axle, placed just behind the bicycle's rear-wheel. The axle rolls on 2 pairs of small bicycle-wheels. This axle is steerable via a chain-based mechanical coupling with the steering system of the bicycle's front-wheel.
The stabilizer adds stability and rear-wheel shock-absorption to the riding characteristics of the bicycle. It enables riding on off-road surfaces.
It adds about 70 cm to the length of the bicycle is about 50 cm wide and weighs about 8 kg including wheel and tire weight.
A cargo-carrying frame can be added on top of the stabilizer chassis and attached to the bicycle-frame's seat-post corner.
The design flows air through the car,
via air-inlets incorporated into the roof, forward floor areas and an air-outlet in the trunk flap.
A mild air-conditioning system is added at the air-inlets.
Glass panels will be used in the roof for both front and rear sections.
A center mounted steering-system is planned with the driver sitting in the center of the front cabin.
The target is efficient aerodynamics and ergonomics.
This design is based on a 100cc moped (gearless lightweight motrocyle) design (shown above) that weighs about 90kg. The engine is petrol-based and provides a mileage of 60 km/L.
The planned design will only use the drive-train of this existing design and target a similar weight.

Large established manufactuers have a basic structural design that has been developed and refined over several decades.
Minor changes are made to this structure, which is primarily the chassis (e.g. BMW CLAR, VW MQB. Merecdes MFA).
Since production happens at very large scale in assembly-line factories, a single design is made for each usage class, and the design is done in-house, over several years, linked to a production process.

The design state-of-the-art is similar to automotive (e.g. Cradle, Diamond, Backbone frame types). The number of chassis designs is a lot larger and design revisions happen
twice as frequently as automotive.
Usage classes are based on engine size and weight.
There is more outsourcing of the design process, and smaller designers can exist, since a new design is a lot cheaper to protoype.

A bicycle is designed as a bicycle-frame only, by a an established brand (e.g. Diamond, Step-through, Cantilever frame types).
All other components that go into a finished bicycle are designed by specialised component manufacturers, such as
wheels and tires,
gear-shifting mechanisms,
brakes,
drivetrain components such as chain-cranks, chains and freewheels,
and shock-absorption systems.
Usage classes are based on terrain, targeted speed, loading level etc.
Of late, DC-motor based drivetrain assist sys

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, 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.

Low-cost commercial pushcarts are typically 4-wheeled with no steering control.
The Unit-Construction-Hub
is a space, an installation and a process repository
for the production of a single land-vehicle unit.
It is a (significantly) lower-cost alternative
to assembly-line production.
It requires a garage-sized space
and the tooling necessary for the production of
a single land-vehicle unit.
It's similar in complexity
to a large, well-equipped repair garage.
We have started prototyping a Unit-Construction-Hub for the production of a bicycle-trailer.