China's transit elevated bus

I thought it was an interesting, if not rather fanciful, concept when it was first proposed many years ago. Now, it seems that fantasy has become reality: a couple of weeks ago, China unveiled a prototype of the road-straddling bus.

The electricity-powered vehicle straddles the highway over two lanes and allows cars to pass underneath. The testing of its brake and power systems took place on Tuesday in Qinhuangdao, a port city in northeast China.

The TEB concept is designed to help China alleviate some of its massive traffic problems. By combining two methods of transportation, the hybrid light-rail train and bus would transport large numbers of people inside its carriages while letting cars pass underneath.

The developers believe this method would be more efficient, in terms of speed and overall cost, than building a subway system. Because the TEB is powered by electricity, the transportation system could also help the country cut down on air pollution.

At about 72-feet long, 26-feet wide, and 16-feet high, a single cabin can transport up to 300 people, according to China's official news agency Xinhua.

A large transit vehicle that can operate along existing rights of way and which allows cars to pass underneath it unimpeded? Sounds exactly like something we here in Houston could use along our congested freeways (or even arterials like Westheimer or Richmond), right? Problem is, it's unlikely that this technology is coming to America for a variety of reasons, as listed by both Human Transit's Jarrett Walker and Wired's Aarian Marshall. Among them:

To run a straddling bus in a real-life city, you must prevent dumb drivers from doing dumb things. Although this thing is nearly 16 feet tall, it has a ground clearance of just 7 feet. (Don’t wander onto the wrong Qinhuangdao street, Kareem Abdul-Jabbar.) It’s entirely possible an SUV could get stuck underneath, and trucks? Don’t even think about it. The standard clearance for an American tractor-trailer is 13.5 feet. Keeping tall vehicles out of the way requires filtering them. Maybe those yellow clearance bars you see in parking garages? Because—roll tape—signs aren’t good enough.

And even with that modest seven-foot clearance, this vehicle is still sixteen feet tall, which is higher than most bridges. Furthermore, how does this vehicle interact with traffic control devices such as signs and traffic signals? A vehicle of this size will require large elevated passenger stations, which aren't cheap, and it would only be able to operate along streets that are perfectly straight or have very wide curves that the straddling bus could negotiate.

Then there's the issue of how other drivers will interact with this thing:

Engineers have to find a nifty way for cars to enter and exit the straddling bus lanes. Yes, you should be totally aware of your surroundings when changing lanes. But that’s not how it works in the real world. People sideswipe things all the time, and run over curbs. The TEB-1 also needs a foolproof way of signaling to cars that it is bearing down on them. “It’s like going under an underpass, except it’s a moving underpass,” says [civil engineering professor David] Clarke. And is there anything worse than being stuck under a moving underpass as your exit flies by?

Not to mention that driving under what amounts to a moving underpass is likely to be a disorienting experience for motorists.

The bottom line, as both Marshall and Walker point out, is that you could get same amount of passenger mobility from a bus rapid transit system, for a lot less cost. Walker, however, concedes that this technology might actually prove itself viable in China:

Having said that, if anyone can pull this off at scale, it’s probably China, which seems to tick all the boxes I’ve identified.  They have the sufficiently centralized decision making, low enough construction costs, ability to do things at scale, and relative indifference to Western aesthetics that this thing requires.  They are also building entirely new districts, which offer the best possibility for actually organizing a place around the correct elevated ground plane. So yes, it may happen, and it may do some good.  Which doesn’t mean it’s not, deep down, ridiculous.

Maybe the Chinese have come up with workable engineering solutions to all the aforementioned concerns, and the TEB will prove to be a technology that is both revolutionary and exportable. After all, the fact that a prototype of this vehicle now actually exists means that this scheme has progressed further than I would have expected, and one never knows what the future holds.

As of right now, however, I'm included to agree with Jarrett Walker: this thing is pretty ridiculous.

Vox's David Roberts has more.