It’s a bridge! It’s a bus! But is it real?


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Since May, the Internet has been a-buzz with the “bridge bus”, a never-before-seen public transit contraption scheduled for a 186 km route pilot in Beijing later this year. The bus straddles existing roadway lanes, creating a moving tunnel-like effect for the vehicles underneath. The vehicle’s Shenzhen-based designers claim that the system can move up to 1,200 passengers at a time (300 per bus), without taking away from existing road space, while at the same time reducing fuel consumption (the bridge bus runs on electricity, partially supplied by solar panels), and at a lower cost than building a subway. A revolution!

I am a big fan of entrepreneurial innovation in transit. And when I see something truly innovative and different come out of one of the countries where we work, I get very excited! But there is something about this concept -- something that doesn’t seem quite right…


The Proposal

Detailed information about the project may be found here, including a video produced by company pioneering the concept:

The Questions

Mind you, I know nothing about this program other than what’s been flowing through the blog-o-sphere. But with my limited perspective, the bridge bus concept would seem to pose a few dilemmas:

1)      This sounds…expensive.

The bridge bus runs on tracks embedded into an existing road. Which means, to deploy the system, unlike a dedicated bus lane or bus rapid transit system, we still have to build tracks – just like we would for a light rail system. Except, these tracks may be more cumbersome, because anytime a city wants to do road or track maintenance, both the bus and the regular traffic systems would need to be shut down (with dedicated guideways, this is less likely). And to accommodate the vehicles’ unique elevation, we would have to build stations that far more elaborate than a typical light rail or streetcar station. In fact, every single station would be like building a pedestrian flyover, but at least five times bigger and with greater load factors -- and bridges are pricey (simple pedestrian bridges over major arterials can exceed USD 1.5 million each). 



For reference, here are some (unofficial) comparisons:



Bridge Bus

Diesel Articulated Beijing BRT*

4-Car Electric Light Rail

Electric Street Car

Vehicle Cost per Passenger

USD 6,666

USD 1,250



Maximum # passengers per vehicle





Estimated Construction Cost per km

USD 1.8 million

(w/out stations and w/out vehicles)

USD 2 million

(w/ stations)

USD 20 million

(w/ stations and vehicles)

USD 6 million

(w/ stations and vehicles)


Frequencies would be about the same, since all three options use dedicated lanes. But city could procure more buses and rail cars than bridge buses.

Same as typical bus in mixed traffic.

Affect on current road capacity

Same capacity, but lower travel speeds

One lane removed per direction

One lane removed per direction

Same capacity

 For alternatives, assumed existing roadway lane dedicated for transit.




2)      OMG! There is a giant bridge barreling towards me and I don’t know what to do!

Dangerous!! Caravan lines of cars traveling in tidy lanes may work in computer models...


Beijing Traffic Jam


Using feedback from proximity sensors, the bus emits a beeping noise to alert drivers that it is coming up behind them. But aside from the potentially annoying, extremely loud, constant noise that would have to emanate from these buses to alert drivers past their cell phones and mp3 players, can we be so sure everyone, including those new to a city, would know how to react?



3)      Does it really save travel time? Does it really benefit the environment?

It seems that since the bridge bus does not travel on elevated infrastructure, and since it doesn’t have a dedicated lane, unless complementary policies are made, the buses will still have to stop at intersections. And they will still have to stop at stations. And since only so many of these vehicles could be purchased (given their likely high cost relative to all other transit vehicles), it is unlikely that the frequency could be greater than, say, a light rail or bus rapid transit system.


System designers quote a litany of statistics, showing how environmentally friendly the system is, based on the fact that the system is electric (with some solar panels thrown in). It would seem worth mentioning that electric-based transit is a very old idea – seen still in operations today in subways, light rail, and streetcar systems. In short, and I am not sure, but it seems like there may be safer and less expensive means to acheive the same environmental benefit... 


4)      So what if it breaks?

Only one company in the world makes these vehicles today, and only one will make them for the foreseeable future. Without open bidding, it may be difficult for cities to keep costs down for procurement and maintenance, and increased risks are also posed – what if the firm that designed this proprietary system goes out of business? That said, every new mode of transport had to have a “first” – should this be a concern?


5)      Wait a minute -- where is this Beijing Mengtou District, anyway?

What makes the concept truly impressive – what has been the source of the buzz -- is that it actually will be piloted in Beijing. But to be clear, the pilot will be implemented in the Beijing Mengtou District – a sparsely populated, mountainous suburb of Beijing, with very little traffic compared to the city center. This seems like a smart choice for such a risky pilot, but at the same time, does not lend confidence that Beijing is taking the concept too seriously…which leads us to our final question --

Is it real? Can it be real?

The Big Picture

The most remarkable feature of the bridge bus is its speed of adoption. After being unvelied in May, it has been slated for a real-life, fully constructed pilot before the end of this year -- and not just in some remote province, but in China's shining capital city. The bus represents a let's go, learning-by-doing, almost cowboy style can-do spirit, racing innovation as quickly as possible into practice. 

The project poses a myriad of questions and challenges. And I wonder, in the haste to implement, was there a peer review or stakeholder consultation process, through which most of these concerns were raised and addressed? If so, what were the answers? And if not, since this is a pilot, should it matter? This certainly wouldn't be the first infrastructure project to have been quickly built without prolonged due process -- think of the legendary Jaime Lerner and his many achievements in Curitiba.  But then, the lack of  consultation and impact analyses would seem to pose fiscal and safety risks, and just as importantly, prevent good ideas for conceptual improvement from being heard (thinking of the lack of stakeholder inputs on the US's 1960s urban renewal craze -- whose aftermath we still struggle with today).

Moving On

Readers – please tell me what you know about this thing, and whether you think it will work! This October, I’ll be back in China and, while there, may try to do some additional detective work. Stay tuned…


Information about the bridge-bus used in this post has been culled from:





Images of bus from:


Photo of Beijing traffic from:

·         Edwards, David and Welch, Morgan. 3 July 2010. “Beijing: Officially Expensive…” The Beijinger.



Holly Krambeck

Senior Transport Economist

October 10, 2010

Stations do not have to be very elaborate. A typical rapid transit station has a platform about 3-1/2 feet (about one meter) high. The straddling bus will work well with a similar side platform about 8' (about 2.5 m) high. Under the platform there is enough room for the sidewalk to continue on through. The only significant addition would be sliding doors that close off the front of the station when the bus is not there. Pedestrian flyovers are optional and may go with regular bus stops as well.

Most maintenance would be no more disruptive compared with repairs around rail rapid transit. Actually most of the maintenance could be done in a way keeping the track itself open during most of the daylight hours.

Oh my God! No the bus won't be barreling towards you. It will be going the same way you are. If the bus came up from behind and your fender or your rear view mirror was in its way, the bus would stop, although it might photograph your car and you might get a violation notice in the mail if you were straddling lanes.

Yes it would save time, provided motorists stayed in their lanes letting the bus pass over them. Actually in most cases it would be drivers overtaking the bus from underneath, saving time for themselves. I do not expect that the bus will be going faster than cars very often. There won't be that many straddling buses in the streets that traffic signals could not give them their own green light while other traffic is stopped.

Unlike ordinary trains or streetcars, the stradding bus could use only one rail for steering. It would be too difficult to keep the wheels on both sides "in gauge". But a rail on the other side together with flangeless wheels would reduce rolling friction and make the bus (should we call it a streetcar?) more energy efficient. By the way, many funicular railways, cog railways, and cable pulled railways up mountains have flangeless wheels on one side and the wheels on the other side guide the trains around each other as they pass in the middle of the route. Another alternative is having no rails and using electronic steering along a line painted on the street.

For just the first route, it is not a big risk for the city. Later, if other companies decide to tool up to make these straddling bus systems, then the city could take bids.

Jonathan Humphreys
November 08, 2010

I am currently undertaking a project for university at the moment concerning this exact problem - Mega City Transport.

Prior to seeing this idea, I had an idea for a 'Stilted Vehicle', however I soon discarded it for making more problems than it solved.

I think if you can't convince people of an idea quickly, and it has to be constantly justified, it is probably not the greatist idea.

Curitiba was mentioned in the blog and proves that simple, well organised infrastructure with simple and exisitng technology can go along way - so many people use this system becasue they have confidence in it, and it is relatively cheap bearing in mind thats all they spend on transport(10% of the average wage earner)

I may be wrong here, but i think i am right in saying the Curitiba transport system began in the 60's, and grew very slowly. People generally dislike change and will be adverse to it.

My point is that maybe the 'Bridge Bus' is too complicated a solution, and instead a step by step process is required for a simpler idea.

p.s. By no means do I believe I am working on the same level as these designers, this is just my educated point of view on the subject, and the Bridge Bus' could be a revolutionary idea...

Auto Air Conditioning Repair
March 27, 2012

People would get used to seeing it just like they have gotten used to seeing everything else that transportation has evolved into in the past.

As far as building the tracks for it, that would be good for jobs in the area and traffic is diverted from road construction all the time, no big deal there.