The Transportation Matrix
Frederik Van De Walle and Peter Cox propose a new way to look at personal transportation. Instead of an evolutionary progression from foot to bicycle to motorcycle to car, they envision a matrix of options that range along an axis of increasing motorization (bottom to top in this diagram, but you could also arrange them from top to bottom), with another axis representing increasing enclosure/weather protection (here shown from right to left).
| Full-power motor -- not enclosed/fewer wheels | Full-power motor -- partially enclosed | Full-power motor -- fully-enclosed/more wheels |
| Small motor -- not enclosed/fewer wheels | Small motor -- partially enclosed | Small motor -- fully-enclosed/more wheels |
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| Pedal/electric -- not enclosed/fewer wheels | Pedal/electric -- partially enclosed | Pedal/electric -- fully-enclosed/more wheels |
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| Pedal only -- not enclosed/fewer wheels | Pedal only -- partially-enclosed | Pedal only -- fully-enclosed/more wheels |