Roughly 90 percent of Tokyo's 13.1 million residents commute to work each day by rail, with a third of those riding their bikes on the "last mile" to and from the train station. The result: as many as 3.5 million bikes left illegally parked on city streets every day, crowding already packed sidewalks and exposing the bikes to weather and thievery.

Since Japan's astronomical land prices preclude building street-level bike racks, the Giken corporation has developed an ingenious solution; simply store the bikes 40 feet underground in an automated bike vault. Dubbed the Eco Cycle, this 23-foot diameter storage facility houses as many as 204 bikes.

To use it, you must first sign up for the service—membership costs 2,600 yen ($30) a month, though students pay half that—and be issued an RFID card. You then load your bike into the hub's locking aluminum runway, swipe your membership card, and stand back. The system automatically opens its storage bay, pulls the bike in, and lowers it to a free slot. The storage process, as well as retrieval, takes just 13 seconds on average.

Interestingly, the system's structural pillions come prefabricated and are pressed into the ground like gigantic fence posts. Its storage mechanism and above-ground terminal are also prefabricated and can be installed as their respective units. And, with Japan's hyperactive geology, the Eco Cycle is designed to handle the region's regular tremors. [Danny Choo - World Changing - Giken - Wired]