Strap-on quad roller skates

A pair of strap-on roller skates allows a person to quickly equip himself with a cheap method and faster than walking-type of transportation, which is usable on streets within the city. The pair of skates would be posted on strategic locations around the city (eg just outside the home, outside at the workplace, ...) As the roller skates would be a strap-on version, the shoes themselves do not need to be switched, allowing to quickly pull the roller skates on while on the street.

Another method to use the skates would be to carry them in a backpack. This method would be useful for people not following a standard route (ie work-home), or in cities that do not have a locker on strategic places, to secure the skates in. This method would also allow people to carry them on (public) vehicles, ie trams, trains, ...

Properties

 * Buildable in low-tech workshop
 * Cheap to construct
 * Made from materials approved by the cradle-to-cradle concept
 * Containing rigid structure, so as to allow use with non-rigid shoes. Non-rigid strap-on roller skates (eg Dualz skates, ... ) are thus not allowed.

Design
The overall design would be quite similar to the Scorpion & Quadline Urban Street Skates. It would however be made somewhat more simple and out of less different types of materials.!

Alternative
A alternative would be the use of strap-on jumping stilts.