For centuries, city designers have looked at road networks, shaken their heads at the traffic jams, and dug great big tunnels under the city to allow for a faster, disruption-free form of transport.
But Song Youzhou, a Chinese designer, has a very new suggestion. He has created an electric "bus" which straddles two lanes of traffic but passes under overpasses, using road barriers as a kind of rail.
Five Chinese cities have apparently signed on to pilot the new form of transport already, and the rest of the world is taking notice. Bai Zhiming, the project's manager, says the system would cost a fifth as much as a subway, which seems convicing given the system requires no tunnelling and minimal infrastructure.
Each bus could carry as many as 1,200 people, and cars would pass easily beneath it. (Lorries would need to go behind it, or overtake in another lane.) It would also run on solar power.
This video introduces the concept, and shows a model of the futuristic vehicle whizzing over traffic jams. Customers would board at road bridges, and if necessary, could evacuate via slides which fold out of the bus's sides:
But as Time Payne, a transportation consultant, points out at Fast Company magazine, we shouldn't get too excited yet:
"For us transit geeks, it's pretty interesting stuff, just to see what people are trying...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."
We still have a lot of questions: the overpass stations seem very complicated, as passengers would need to descend into the vehicle from above; and lorries seem like they'd cause no end of trouble. As Cory Doctorow points out at Boing Boing, videos also appear to show the vehicle bending as though made of rubber, not steel. That doesn't mean it isn't a very cool idea, though.