Written by by Kate Springer, Sol Han, CNN

In Tokyo, 14% of commuting traffic is on bike, according to the Japanese Transport Ministry.

But you'd never guess it.

That's because the Japanese capital is burying thousands of bikes in underground parking vaults, in a bid to keep its sidewalks tidy.

From street level, an Eco Cycle looks like a small kiosk --a 560-square-foot hub with a door that seemingly leads to nowhere.

In reality, these stations are gateways to futuristic subterranean parking lots, which each plummet nearly 40 feet into the ground and are home to hundreds of tightly stacked bikes.

Storage solution

In Japan, 78% of households own a bike, compared with 50% of those in Britain, according to a 2014 study by the Pew Research Center

"It's a blessing and a curse," says Chad Feyen, of The Cycling Embassy of Japan , which is devoted to promoting cycling and improving bike infrastructure.

An Eco Cycle elevator in Tokyo, Japan. Credit: Keith Tsuji/Getty Images AsiaPac/Getty Images

"You have a lot of cyclists, but you also have a lot of bikes clustered around Metro stations. It can be dangerous, or at the very least take up space."

Eco Cycle aims to encourage cycling, but free-up space on Tokyo's crowded streets.

"In Japan, there are many illegally parked bicycles in city centers," says Tsunenobu Nozaki, manager of construction design and planning at Giken , the Japanese company which invented Eco Cycle.

"If a bicycle park is far away from the cyclists' destination, no one will use it. "

Gone in 8 seconds

Cyclists can store or retrieve a bike at an Eco Cycle station in just eight seconds.

These efficient subterranean parking lots also protect bikes from rain and theft, while the seismic-resistant shaft is designed to withstand earthquake tremors.

A man loads his bike at an Eco Cycle. Credit: Keith Tsuji/Getty Images AsiaPac/Getty Images

The first time a cyclist uses one of these facilities, a smart locator device -- called an IC Tag -- is fitted to the front of their bike, which correspondents to the smart card they are provided with.

Cyclists swipe their cards at a check-in booth to activate the loading mechanism. Their bike then disappears through a small entryway and is lowered into the compact storage system below.

slot in Tokyo. An Eco Cycle parking space costs about $25 a month, compared with over $700 a month for car parking slot in Tokyo.

Subterranean success

Today, there are 50 Eco Cycle stations across Japan, with a global expansion in the works.

The bikes are stacked underground. Credit: Keith Tsuji/Getty Images AsiaPac/Getty Images

"We regularly receive inquiries from other cities," says Nozaki. "(We plan to) license the design and manufacture of Eco Cycle so that local manufacturers can design and build units in their country."

However, the design is not without its skeptics.

"I think (Eco-Cycle) is a great idea and the technology is fascinating. But I personally don't feel comfortable with my bike going underground," says Feyen.

"If there's an earthquake or an emergency, and I want to get my bike out -- I want my bike to be near me."