A handful of Chinese cities plan to begin testing a new solution for urban traffic jams: a huge electric "bus" that glides over traffic, carrying as many as 1,200 people inside. There's room under the elevated bus for two lanes of cars to keep driving. Watch it here:

The designer says it's significantly cheaper than building a subway (at around $4.5 million per bus) and can replace 40 normal buses. The system can run partly on solar power, potentially reducing more than 2,000 tonnes of carbon emissions from an equivalent fleet of buses.

But it isn't necessarily practical. "I would say that under a very specific set of circumstances, something like that might have an application," says Tim Payne, principal at Nelson\Nygaard Consulting Associates, a firm that designs transportation systems. "But some of the issues of making it fit into the built infrastructure are far more complicated than the typical BRT [bus rapid transit] operation."

Bus rapid transit, a system now in hundreds of cities around the world—including many in China—dedicates or partially dedicates a lane of traffic to buses so they can travel more quickly and reliably—more like a train, but without the massive cost, and without the need for rails as in this design.



In the U.S., where bus rapid transit continues to spread, the new straddling bus likely wouldn't work with existing infrastructure. "Something like that would not operate very well on an arterial, nor would it be very adaptable where there's a lot of overpasses," says Payne. Trucks, which are typically allowed on all roads in the U.S., wouldn't fit under the two-meter high "bus." Intersections would pose more problems, as cars would be forced to wait for the giant bus before they could turn.

"The more interference there is between transit versus traffic, the less you can optimize on speed and reliability," he says.

Song Youzhou, the designer of the elevated bus, says that five Chinese cities—Nanyang, Qinhuangdao, Shenyang, Tianjin, and Zhoukou—have signed contracts with his company, TEB Technology Development Company, for pilot projects of the new transit system. But another pilot project in Beijing was cancelled when experts criticized the design.

"For us transit geeks, it's pretty interesting stuff, just to see what people are trying," says Payne. "While they're very different in the approach, it's not all that different from Elon Musk and the Hyperloop. . . . Putting that video on the Internet with the intention of raising capital, one does not want to talk about downsides."