Archive for the ‘BRT’ Category

Is Montréal paying too much for BRT on Pie-IX?

Friday, October 1st, 2010

According to a recent gazette article, the cost to build 15km of bus rapid transit along Pie-IX is projected to cost 305M$. This includes154M$ for 10km in Montreal, 125$M for 5km in Laval, and 26$M for unforseen expenses. The higher relative cost in Laval is due to having to modify on/off ramps, and building parking lots.

Now Yonah Freemark at the Transport Politic asks whether Montreal might be paying too much. He compares that to Besançon, a small city which prides itself building the cheapest TRAM system in France:

It’s a question Americans should be asking themselves, since the costs of transit investments seem to be spiraling out of control even as the demand for alternative transportation options has increased and the funds to support them have diminished. Besançon, a city of about 115,000 in a region of about twice that size, has managed to develop a project whose costs are acceptable — “optimized,” the local transit agency calls them — even in a small metropolitan area.

Besançon will be getting a light rail line fully in its own right-of-way that extends over nine miles and thirty stations, all for a price of €228 million ($310 million), with construction beginning this fall. The city expects about 43,000 daily riders once the project opens in 2015. This is no streetcar, and yet plenty of U.S. cities are thinking about spending far more per mile on those limited ridership, low-performance systems.

He goes into a further analysis on how they cut costs, by avoiding surface construction as much as possible (i.e. ban cars instead of rebuilding streets) keeping station design simple, and getting the best prize on their rolling stock. Apparently the city negotiated with six candidates to produce the rolling stock, fostering competition. It then awarded the contract to CAF (the Spanish company that would like to build the Montreal metro cars..), and now pay 30% less than Houston for similar technology from the same company. The lower cost is partly due to not requiring much customization.

The example might not be very comparable to Montréal, and what the city hopes to achieve on Pie-IX. And one could argue that if you buy cheap you get cheap. But in the end of the day, the desire to keep costs low on transportation projects is a virtue that seems to be lacking in Quebec, and the rest of North America. And it means that tax payers will pay more to get less, and will have to wait.

Thoughts on Bejing’s “3d bus”

Wednesday, August 11th, 2010

A couple of days ago, chinahush.com posted a video (in Chinese, English translation included) showcasing the concept of a bus running above traffic. The idea is that the bus is basically a moving tunnel, with a 2 meter clearance below for normal car traffic to drive under. Thus the bus can drive above traffic without being stopped by traffic jams or without stopping traffic when it is itself stopping at a station. At the same time, the bus still fits under overpasses. The buses are four carts long, each cart taking up to 300 passengers, and are supposed to go up to 60 km/h.

This seemingly solves to problem of creating right of ways for public transportation. Subways have their own right of way, unimpeded by any other traffic, and not interfering with anything else. But they are also the most expensive. Elevated tracks also represent a dedicated right of way, but they might disturb the cityscape, due to noise and darkness below, and will only fit along certain streets where they still may take away some space due to heavy construction. Buses usually don’t have their own right of way, except for bus rapid transit. So buses may get stuck in traffic and also may – from the point of view of drivers – create more traffic. Of course a bus may replace a large number of cars. On the other hand subways are the most expensive, while buses are the cheapest (at least in terms of initial construction). So the “straddling bus” may give both advantages, of creating it’s own right of way but not disrupting traffic, by simply bringing it’s elevation structure along with itself — basically, it is its own overpass. The claim is that the cost is about 10% of what a subway would cost.

Dario Hidalgo over at The City Fix brings home the point that this concept might not actually solve any real issues:

The plan is really innovative, but seems to be at a very preliminary concept stage with too many issues to solve from the engineering standpoint. For the time being, it would be much better to dedicate time and effort to simpler and more effective transit solutions, rather than making concepts that preserve space for cars.

Another issue is that to make this system work, one may have to make some compromises which will actually make this system inferior to already existing systems like bus rapid transit or light rails, although some of the ideas could maybe be reused here.

Any information besides the video, which may very well come from a TV show where the audience has to guess whether presentations are fake or not, is hard to come by. Let’s just assume this idea is for real and will actually be implemented. And since I like innovative transit concepts, I decided to take a closer look, and at some of the issues that come up.


keeping away trucks

The clearance below the bus is planned to be 2m, which means that trucks will not fit under it. Some of the images show this bar construction presumably to keep trucks away. It seems to me that this is not enough to keep trucks actually separated from these lanes. There are already problems with drivers who are not aware of low clearances and drive into these areas. It would seem that a more solid approach would be more appropriate.

At other points in the presentation it actually shows trucks driving on the same lane as the bus. Some sensor system in the bus would detect that the truck is too high, and will warn trucks to change lanes to avoid a collision. This is an even more dangerous approach. Drivers now have to be even more aware of low clearances ahead — of another moving vehicle — and then react to some small display at the rear of the bus telling it to switch lanes, which might not always be easy. Another issue is that the bus might be driving up to a truck which is stuck in traffic ahead of it.

Even if drivers were vigilant enough, it would mean that the bus cannot really drive much faster than the slow moving traffic for safety reasons — and if the cars are stuck, and there is a truck among them, then the bus will be held up as well. It would probably be best to completely separate all tall vehicles away from any lanes where the bus can go, and make sure of that with barriers that cars have to drive through before turning onto the bus lanes.

This would mean that there would exist a secondary grid where only cars can go, which might be quite a hindrance for any traffic of large vehicles. Even on a four lane boulevard where only half of them will be low clearance, it will create problems for large vehicles to turn left or right (depending on whether the bus lanes are the inner or outer ones). This is somewhat ironic — usually trucks delivering goods or other high occupancy vehicles are the ones that should get somewhat of a priority, but this scheme completely seems to prioritize individual car transport. And if there are only two lanes to begin with, like in the picture on the side, then any large vehicles can’t go there at all. I wonder whether just dedicating one lane to either BRT or a light rail would create less of an impact on other motorized vehicles.


avoiding collisions

Even if trucks could be reliably kept away, there is still the issue of avoiding collisions. Imagine driving on a highway in heavy traffic, and having this thing whoosh over your head. The presentation shows that sensors in the bus would detect vehicles that get too close and warn them with lights and sounds. This will create a very disorienting situation with all sorts of conflicting visual information from all sides and little visibility of the fixed environment. And if there is an accident, hitting the bus from the inside, it is quite possible that a lot of people might get hurt. It would probably be better to create railings behind which the bus drives, to minimize the chance of bad accidents. It would also ensure that no vehicle crosses from a bus lane to a non bus lane as the bus approaches from behind, which will slow the bus for sure, if it doesn’t cause an accident. Again this will increase the amount of space needed for the whole contraption, meaning that one could just dedicate a single lane for a more proven form of transit.


tires vs tracks

From the presentation it is not very clear whether the vehicle is running on rubber tires like the name ‘bus’ suggests, or running on tracks like a streetcar. Besides the problems of staying exactly on track, having such large and heavy vehicles go along the exact same path on the road presents some problems. Bombardier experimented with a streetcar bus hybrid, called Guided Light Transit. It’s basically a streetcar vehicle running on tires, guided by a center rail. The idea is that it can operate like a streetcar in downtown, but does not need the rail along it’s whole path, giving it more independence and flexibility over a regular tram. The hope was that this system would be cheaper. But one of the problems is that due to the heavy vehicle always riding over the same spot, the asphalt deteriorates much quicker. Adding to that the added maintenance requirements of rubber tired vehicles, and the system actually turned out to be more expensive than a regular tram. The Bombardier vehicle only weighed about 40 tons, while the straddling bus should be much heavier. Thus rails would really seem to be the only option to ensure that the bus is properly guided and the maintenance is manageable.


stairs

Having stairs inside a transit vehicle at first sight seems like a good idea. Due to the wide width of the bus, one can easily fit stairs inside it while still leaving space on the sides to pass. This would allow entering through and exiting to (existing?) overpasses, and would reduce the amount of engineering required to build stations. One would merely need pedestrian overpasses that are required over very busy roads anyway, and no actual platforms where the bus would have to stop.

The main problem is that entering and exiting through stairs will hugely increase dwell times. In usual rapid transit, passengers enter and exit through many doors and level boarding will make sure that the time required to get everybody out and in is fairly small, in the range of a few seconds. Decreasing the number of steps required reduces the boarding time, that’s why low-floor buses and streetcars are becoming the standard. Level boarding is also one of the ways Bus Rapid Transit achieves high throughput. Instead of requiring a few steps, the image shows a full flight of stairs. This does not only impede accessibility, but also increases dwell times to the point where the overall average speed of the bus will hardly compete with normal street running buses.

Probably to increase throughput, the presentation proposes this oval shaped overpass, which appears to allow two sets of stairs. Not only will this reduce the capacity inside the vehicle, but it will also mean that the amount of engineering required will not be much different than having an island platform below a simple overpass – thus it makes the case for stairs moot.


power transmission

One interesting aspect of the straddling bus concept is the way electricity is to be transferred to the vehicle. As opposed to having an overhead wire and a pantograph attached to the vehicle, the proposal is to use fixed pantographs and a conducting rail on the roof of the car. The distance between two charging poles is smaller than the length of the vehicle, so that it will always get charged. This seems like an interesting idea, and I would like to know the cost of such a system compared to using good old overhead wires.

Another mentioned idea is to use supercapacitors and only charge between stations, making the 3d bus an actual capabus. Super capacitors have a low energy density compared to lithium ion batteries, but allow to be charged much quicker. This it is possible to charge an electric bus at every stop, so that overhead wiring is only used at stations. This idea is not new, and already Shanghai has some capabusses running since 2006.

How a Bus is a Metro in Bogotá

Saturday, May 29th, 2010

I previously mentioned that transit has received some creative ideas to implement systems outside of the old paradigms of subway, streetcar and bus. One of these ideas is to run a system of buses as a sort of surface subway, called bus rapid transit, or just BRT. The canonical example is Bogotá’s Transmilenio. It is a relatively young system, barely 10 years old, but it has reshaped transport in the whole city, and its success created a movement to replicate similar services all over the world.

The system basically consists of buses running at high frequency to improve capacity, and actually approaches and surpasses the throughput of some of the world’s metro systems, by using a few essential tools:

How It Works

The entire bus network is run on dedicated lanes, separated from regular traffic. The lanes are usually in the center of a road, often along High Ways to reduce the number of intersections. The stops are built similar to metro stations, with raised platforms and payment of fares at the station entrance. Thus, boarding is level (no steps up or down) and happens through all doors of the single- and double-articulated buses. These features reduce dwell times while increasing capacity.

These techniques were actually pioneered in the Brazilian city of Curitiba in the 70s. Although Bogotá was not the first city to build a system like this, I would still consider its system to be the prime example, as it is a much larger metropolis than Curitiba, with more than 8 million inhabitants vs fewer than 2. It also stands out by the speed at which the system was set up, the branding used to differentiate it from previously existing buses, and the conscious choice to built the much more affordable BRT instead of an expensive metro.

Back in 2000, another option was to build 30km of metro. Instead it built BRT, which is planned to eventually reach 388km – at only 10% higher cost than the original metro plan would have been.

At the same time the city also measures to force people off the car and into the bus. These include restriction driving during certain times of the day according to the license plate numbers, huge staffed bicycle stations around the Transmilenio stops and weekend closure of highways.

The BRT Wave

It’s interesting to see innovation and integrated transportation planning in the developing world, instead of some attempt to replicate existing systems developed nations. The Transmilenio has become a new mode of transport, distinct from the bus, and people will actually say “I am going to take the Transmilenio” (well, more like “Voy a tomar el Transmilenio), instead of just the bus.

Today, cities all over are building their own BRT. For example, Guangzhou just opened a surprisingly similar system this year, emulating all the techniques of the Transmilenio.

Even in North America transit agencies are jumping on this BRT wave. Most recently, the MTA intends to create a “surface subway” along Manhattan’s east side, to be used while an actual subway is being constructed. However, for example in Cleveland, these are half-hearted attempts, lacking dedicated lanes, in-station ticketing or level boarding – and, well, speed. It seems that in North America, few planners dare take away lanes from the car. Jarret at Human Transit collected some question to ask about BRT, providing a list of properties of ‘true’ BRT.

Issues

There are some pitfalls even when implementing actual BRT. Some relate to speed (which is always going to be lower than a subway), most related to costs. One problem is that running a large number of buses is much more feasible in the developing world, where wages are low. At the same time, the cost to run the system is closely related to fuel costs – which will keep rising.

The system also requires more maintenance, both on the upkeep of the right of way (steel rail vs paved road), and the vehicles themselves, which have to replaced much more frequently. This is one of the main reasons why Ottawa is going to replace it’s busway with a light rail that goes through downtown underground. Despite a 2.1$ billion capital investment, the city hopes to save 100$ million annually on operating costs, while increasing capacity.

Another issue is the placement of stations along huge highway corridors, often far away from riders’ destinations, forcing them to traverse large distances across polluted concrete deserts. The pollution coming from the buses themselves should not be ignored, either. Moreover, even when stations are in more downtown areas, these large obstructions are often not well integrated into the urban fabric.

Maybe in the long term, as labor and diesel costs become unmanageable, the system fills up, and the pollution becomes too much of a burden for this high altitude city, Bogotá will convert to a rail solution. Already it has concrete plans to build its first metro line, whose construction is supposed to start this year, and which is to be opened in 2015. But in the meantime the city seems to have found an effective and affordable solution to it’s transportation problems.