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China to build giant buses that cars can drive under (engadget.com)
116 points by garply on Aug 2, 2010 | hide | past | web | favorite | 57 comments

Are those really busses or are they trains? This scheme looks cool, until I try to picture what happens during turns. Remember that "large vehicles make large turns." One way to think about it is that "turn radius" of the from wheels is much larger than for the back wheels. It's more complicated than that, but it's the gist.

EDIT: Watching the video now. The "bus" is divided into many sections which need to "snake" around turns. This fact is fudged a lot -- many of the illustrations also show vehicles that do not have joints. Judging from the size of the bending joint sections, the minimum turn radius of the bendable trains looks fairly large.

This strikes as feasible, assuming total computerized control of all the vehicles, both the "bus" and the cars trying to drive under it. Humans will be smashing the sides of that bus with frightful regularity, though.

And by the time you have that, there are probably way better ways to deal with traffic than this sort of crazy contraption. Even if this ever becomes practical I have a hard time seeing it ever being the best use of money.

Segmenting the bus enough to give it a safe turning radius will make it seat very few people. (And note I don't say "decent" or "cost-effective", I said safe. If cars are driving underneath, the "bus" must also turn exactly like a car.)

Nifty concept, pretty pictures, much less practical than the only-barely-practical-if-that trains that don't have to stop that got posted four or five times a few months ago. But worth noodling around with; I don't fault the designers too hard, I fault the credulous media.

Humans will be smashing the sides of that bus with frightful regularity, though.

I'm pretty sure Houston drivers would be. They can't even deal with light rail on city streets!


Based on my own observations I take it as a given that people regularly break traffic rules. Car-car smashes happen with frightful regularity too. It isn't a Houston-only issue.

The reasons for this may be carelessness or disregard--reasons don't really matter. The behavior exists and rules/signs don't appear to mitigate very successfully (especially strange signs and irregular rules you don't see anywhere else).

Carelessness and disregard are part of the human condition and why defensive driving is great. It follows the robustness principal of "Be conservative in what you send; be liberal in what you accept."

Unfortunately, the performance envelope of Houston's passenger train precludes defensive driving on its part. It can't be a good street-citizen.

Having lived in Houston for 7 years, I'd say we have a much bigger problem with the car drivers not being "a good street-citizen." I wouldn't say it's Houston only, but there is a lot of it here. There's a lot of just plain pinhead disregard for physics and common sense here.

I've never been to Houston, but I've been to a lot of US cities, and I've been to China. I find it hard to imagine that the drivers in Houston are worse than the drivers in China.

I've heard first hand descriptions of driving in China, Italy, and Pakistan. In Pakistan, they have problems with people obeying stop lights!

This all just supports my point. If Houston drivers are pinheads that feel like they can cut-off a train that out-masses their vehicle by a factor of ten, what are Chinese drivers going to do about these massive tunnel-things going around when they have to drive underneath those things? It's begging for a lot of accidents, I think.

Yeah, i've been to Beijing and people don't really seem to drive in lanes there. It would be really nice if they could get this to work, but it seems a bit utopian.

He says that there are radar detectors that will set off alarms and light signals and automatically call the police if cars get too close to the edge. It's designed to seat 1200 people apparently. And construction meant to start by year end so I suppose we'll know soon enough if it really works.

"automatically call the police if cars get too close to the edge"

When fractions of a second matter, the police are only minutes away...? Not sure what calling the police will do.

Because a person likely to set off the alarm is likely to be driving erratically, meaning a high probability of being DUI. Not everyone who sets off the alarms will crash, but there could be a high proportion of them who could easily harm someone else on the road.

Although by the looks of this system it is to be similar to a rail system, so I'm unsure if a side-on-side collision would even be capable of derailing this and causing serious harm.

Honestly, I'd be more worried about car-on-car crashes under these. I've seen how stupid people are driving under bridges. Despite no shape-change in the lane, people tend to drift away from any walls or support pillars as though they're afraid of hitting them, and I've seen it to the point of them cutting other drivers off.

Stop them doing it again next time after they get fined.

The turning/signaling will follow that of BRTs.


Basically the car traffic will be signalled to stop, giving the bus priority.

Are those really buss[^H]es or are they trains?

You can cross the bus with the tram:


...with the articulated bus: https://secure.wikimedia.org/wikipedia/en/wiki/Articulated_b...

I guess it is a stretch, but I love this type of thinking. For one, if they could make it work then it would be a fantastic use of space, which is your primary concern for public transport in heavily urbanised areas.

It is important to be realistic, but I also think that this type of thinking is notably absent from U.S. society. The thing that defines Chinese innovation for me is that it is based almost exclusively on urgent necessity, which is always a great environment for progressive ideas.

For one, if they could make it work then it would be a fantastic use of space, which is your primary concern for public transport in heavily urbanised areas.

Is it really a good use of space?

For one thing, it means all your roads have to have some huge overhead clearance, which stops you from having overpasses et cetera.

Secondly, your road has to be made wider to put the bus there anyway, since you need space for the bus wheels. I doubt that the extra half-lanes you need for the wheels on either side of the road will be much less than one full bus lane.

Thirdly, every bus stop, which was previously just a metal post sticking out of the concrete, is now a complicated two-storey structure with stairs.

And that's before we get to the problem with turning the damn thing. You'll notice that the video depicts this bus on an insanely wide road; I have difficulty imagining it in an area where space really is at a premium, and in such a place I can't imagine it'd really take up less space than, say, a dedicated bus lane.

The video says that when the bus has to turn, it will turn on the red light for the lanes under it that is not turning with it.

It is not uncommon to have green light for buses (esp. w. bus lanes) before the other traffic gets the green.

>Are those really busses or are they trains?

According to the video it's a hybrid. When there's no rails you need to paint special lanes, and the lane-assist system will keep the vehicle on track. From the operator's point of view it's driven like a train.

First thing that jumped out at me was cars under it trying to make a turn... I think both of those would work with bridges that the bus would use around turns (picture on/off ramps on highway)

This effectively becomes an elevated train with a vastly less expensive infrastructure buildout. Genius.

Not sure the infrastructure is likely to be that much more inexpensive - the requirements for smooth gradients and strong foundations are going to be more than your average rail line, and they'll need to pay incredible care and attention paid to intersections.

That's even before they've taken into account the costs of building and testing enormous custom-designed vehicles rather than using tried and tested technology.

Alternatively, they could have sacrificed slightly more road space for a conventional light rail system, or even a bus lane and all the flexibility that comes with regular buses....

Their Trams

Given the nature of traffic in China the one angle they don't show in the video is the one that matters most... what happens when vehicles in front of the bus straddle the lane, blocking it?

They line up neatly coming from the back because they physically have to but anyone who has seen the traffic in China knows that cars will not get out of the way or obey the lane markers and are quite likely to abruptly (even at risk to themselves or their vehicle) cut the thing off from the front in order to squeeze in front.

The same way we solve all of life's problems: Giant spinning blades!

Or, y-know, fines. And a bored cop sitting on the top of the giant bus with a crane.

I thought the exact thing. Traffic in China reminds me of a school of fish - cars wiggle and dash in front of one another with total disregard for lanes.

Think of it the other way around: cars don't drive underneath, but the bus drives above the stationary cars in the congested metropolis.

The congested cars in China aren't neatly stacked in their lanes.

Took me a while to understand the concept because of this confusing title. I first thought those buses would move the cars around, like giant ferrys.

Neat idea but it violates the 'kiss' principle on several points.

I'll believe it when I see it, in spite of the fact that 'building will commence soon'.

It is simple in a way. It's an alternative to building another deck on top of the road for light rail to run along. Probably cheaper and less devastating to communities that it runs though.

Not really, building another deck on a road (assuming that's the right solution for a given topology) is well understood technology wise. Adding a completely new, untried infrastructure for a vehicle class that nobody has any experience with will add unique challenges that may be difficult or even impossible to overcome. In practice, for instance, how would you deal with it if one of these monsters broke down? What will you do when a car has an accident with another car underneath one of them in such a way that you can't move it without further risk to the occupants?

How will the drivers deal with a vehicle that is in their perpetual dead angle ? How will the driver of the 'urban train' see the vehicles he's moving over and make sure that none of them get crushed at intersections in case traffic somehow got blocked?

China has some history of 'grand announcements' which are then not followed up on, and a few that they did follow up on that failed fairly spectacularly. We'll see if this one works out, I'm sceptical but who knows, maybe it will work.

The three gorges dam is also still holding up in spite of lots of nay saying so I'll give them the benefit of the doubt.

I don't think that it's such a great idea.

ACCESIBILITY: In crowded cities you need people to get in and out of the bus quickly, meaning lots of doors and very few steps. Also let's not forget wheel chairs. How could an elderly person climb all those steps to get out of the bus? How about someone with a baby in a buggy?

INFRASTRUCTURE: Yes, it's cheaper than a subway, but that's the only advantage. When this bus makes a turn, at least some part of the traffic must be stopped. Cars will crash into the bus without doubt. The bus stops will be expensive to build.

SUGGESTION: Spare two lanes and build a light rail, separated from the traffic by fences solid enough to prevent cars from landing on the rail. Make all intersections with regular traffic at different grades (overpass or underpass). It's a proven technology, no accesibility issues, cheap stations, completely separated from the rest of the traffic (because of this it can become completely automated).

Why not just build the light rail over the highway, like they do in Bangkok?

I hadn't read about the rail in Bangkok, looks cool:


It's more expensive than on street level. But they could build the rail over the highway in very crowded areas, keep it at street level in areas where land is cheaper, and even go underground for short distances (ie: to pass crowded intersections). It seems way more flexible to me than this bus idea.

You make this sound like a new idea---many cities have had elevated trains as part of their mass transit systems, and some still do. Chicago is famous for it (and the Chicago El is more than a hundred years old).

I wonder what their turning radius is? How will they turn around at the end of the route (I would imagine probably just switch back like a train). Thanks China for another crazy but awesome idea.

It's a cool innovative idea. Now it's the execution, which probably won't be easy. Vehicle design and construction will be different from norm. Road design and regulation will be different. Kudos for coming up with the idea.

This looks dangerous. Two lanes of traffic competing for limited space under a moving bus? Imagine what happens when a car underneath hits the side and goes into a spin.

If both 'layers' of traffic are moving, not sure this is any better than a double-decker bus. Certainly, it has less route flexibility, if it requires special rail/roadway support.

My hunch is that computer-driven cars are the real transport innovation we should be concentrated on. When a region can go 100%-auto-auto, it will increase road capacity and eliminate congestion, without tearing up roads with massive new (and inflexible) rail construction.

There must a transport revolution going on in China. It instantly reminded me of this video:


These trains that never stop seem a lot more feasible than the buses. Granted it would require a massive amount of work from an infrastructure perspective but it seems like such a brilliant solution that would make public transport infinitely more appealing.

This was posted to HN before. The comments on that were basically, it's been done before, and wasn't economical/safe. Keep in mind, you still have to spend energy to accelerate the cars, and there are a lot of safety issues introduced by the extra complexity.

This is reminiscent of the way the old-fashioned cablecars worked (and still work in San Francisco): the cable snakes through the system and is operating at full speed always, while the cars start and stop by slowly releasing or catching the cable.

This concept was brought up in one of the Patlabor anime movies, except instead of buses, it was police/fire/ambulance/emergency vehicles that could move over congested traffic to get to an accident scene more quickly.

Kudos to the Chinese for being willing to try it out, but the concept existed at least in 2001(if it was Patlabor 3) or 1993(Patlabor 2)

I ride the bus to work most days. A lot of the drivers like to gun the engine when they can and stop quickly. This is annoying in a low-slung bus and would be scary in one with a high center of gravity. Much of the route has old, beautiful trees along it--not much change for them.

How is it driven? It looks like it would be a disaster if the bus weaved left or right by a few millionths of an inch.

Adds a whole new level of enforcement to the left turn only lane.

An excellent idea, maximizing use of the available road space.

US to build giant pickup trucks that SUVs can drive under.

Odd that all the CGI people in the movie are white.

Probably stock models that came with the animation software.

And everybody drives SUVs and sports cars.

Maybe one day, say the year 3000 cars will be driving under cars, under cars, under cars. We can only go up to the skies.

I guess hackers don't like predictions so much. Who is to say that such wont be the time in one thousand years. Are we going to dig down to earth instead, rather than find more effective ways to use the very finite space on earth.

They did not start building high buildings for no reason. Why would the solution be any different if a solution one day our roads needed?

Then, one day, boom--stack overflow. Civilization collapses in a cosmic recursion-induced segfault.

this is so beyond cool...

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