Ian Bicking: the old part of his blog

On the subject of mass transit

The Oil Drum has a discussion about a report on car-use in Manhattan.

The basic conclusions are that low-volume passenger cars are taking up space and causing traffic problems, while having low value to the area. I.e., people aren't providing business or an economic incentive, they could use mass transit, and they are getting in the way of high-value traffic like deliveries and high-capacity passenger vehicles like buses.

The response to things like this is often to punish low-volume passenger vehicles. Some of these options are implemented in a very dumb way. For instance, encouraging medium-volume passenger vehicles with special lanes for vehicles with more than one passenger. Usually the poor delivery trucks get stuck with the rest of the traffic. Or parking is constrained and/or expensive. Or there's a toll for all vehicles entering the central business district, like in London.

Not surprisingly, it doesn't make people happy to be punished. It's also a really lame response. If people are using cars instead of other options, then why?

I think it is because mass transit sucks. It sucks a lot. Horribly. There's sometimes a perception problem, sometimes an intimidation factor, but mostly it's just that mass transit is awful.

I say this as a person who uses public transportation and actively dislikes cars. But that doesn't blind me to the real disadvantages of our current options.

There are incremental ways to improve things, without using a stick approach:

Still, I'm not optimistic. The basic structure of mass transit is ineffective. It feels like the mainframe of transportation systems. Toss a bunch of people together and into a batched process, ignoring latency while optimizing for bandwidth and forcing people to adapt to the system instead of adapting the system to the people. The result is slow and uncomfortable. It also scales in only one way: it handles large number of people coming and going from the same location at the same time of day. So long as the number of people remains within capacity. Once you go over capacity the system starts to collapse. If people have a wider variety of start and end points, if they are traveling different distances, if they are traveling in different densities at a variety of times it doesn't work. As mass transit it never will work.

Cars scale pretty well. The door-to-door experience is well thought out. The result is an extremely ugly community (parking lots and traffic lights everywhere), but the transportation portion works. Though there are scaling problems as you move from free-flowing highway traffic to regulated local traffic, the service provided is complete. Traffic and parking is a problem these days, but car-based transit has improved continuously and dramatically in the last 100 years, in response to demand. We're seeing diminished returns and reaching the scaling limits, but we shouldn't discount what's been accomplished so far. Mass transit has only improved in very small ways. Cars-based transit is like packet-based networking; we know how superior that model is for internet traffic, and the benefits of that model are just as relevant for transit as for internet traffic.

All this is my long-winded way of getting to my real point, the thing I actually feel optimistic about: we need dramatically different public transit that is not mass transit. We need to revolutionize public transit. We can't put up with these horrible systems we have today. It isn't honest to push these systems as though they are something they are not. It isn't honest to encourage communities to invest many billions of dollars in systems that we know don't work.

People often say "we need a good transit system like in New York or Chicago". I don't know the NYC transit system well, but I can say without a doubt that Chicago mass transit sucks. The traffic sucks too, as does parking, so the mass transit is relatively less sucky than elsewhere. But it still sucks. Please don't use us as a model.

I've already gone on for too long, but I will say that I am thoroughly convinced that what we need is Personal Rapid Transit (PRT). PRT is an automated rail-based system with small cars (typically 1-3 passengers). Service is direct, and stops are made offline -- when one car stops it doesn't hold anyone else up. The systems are as small and light as possible. No 20-ton vehicles to carry around at most one ton of passengers. The systems won't be built in spoke-like systems with hubs as transfer points; instead they use a series of intersecting loops that provide coverage without centralization. Redundancy is built in. New systems can come online incrementally, and every addition expands the overall capacity. It looks a lot like the internet.

The result has the potential to provide better service than cars for most cases (you still can't go camping via PRT). The capital costs are lower than any other rail-based transit, and compare well against roads. Service is provided faster and more comfortably than a bus. Because the system is made as light as possible it is feasible to have lots of stations, giving good coverage. Because of the ease of expansion and adding connections, it can work well with other kinds of transit, and adapt to the community.

The technology is not mature, but this is a benefit. Traditional mass transit is mature, and thus we can't expect them to get substantially better anytime soon (automobiles are also a very mature technology, and we're seeing only very modest advances.)

We know how traditional transit works, and we know it works poorly. With PRT we have a system with future potential. Despite the fact that PRT is an idea that has languished for years, it is an idea that is so cool I can't help but feel excited just thinking about the positive effects it could have on a community. And the crazy thing is that it is not even very high tech, and even the most conservative claims of its potential are revolutionary.

If you are interested, a good place to start reading about PRT is the Innovative Transportation Technologies quick links page, which has links to studies, advocacy, and criticism of PRT.

Created 14 Mar '06
Modified 15 Mar '06


Car drivers may not like be "penalized", but non-car-owners don't necessarily love the tax incentives that subsidize car use (e.g. free highways, gas prices managed through military activities, etc.)

# Bill Seitz

I certainly have no love for cars, and appreciate there's a lot of hidden costs, and that those costs should be born by the people using cars. But I also think many anti-car people are using the car subsidy as an unwarranted excuse for the failures of mass transit. People won't use mass transit, and they hope through ever increasing punishment they can get them to use mass transit, even as the mass transit systems stagnate or even decline in utility. The next system should be better than the last, it shouldn't just rely on a collapse of the last system.

# Ian Bicking

Nicely done. Let me add my 2c:

  1. Mass transit works well only in densely populated areas. It is a simple fact of life. Basically your trip consist of 3 components:
  1. the trip to the departure station
  2. the trip itself on a mass transportation system
  3. the trip from the arrival station.

Let's assume that the tolerable trip to/from a station is 15 minutes. If you walk, it means that it is approximately 1 mile long. Now imagine a 1-mile sphere around your station. This is a service zone. You better have a lot of people living/working/visiting here. You need skyscrapers to utilize this volume efficiently. Some underground facilities (like underground malls) will be helpful too. How many U.S. cities fit the picture? New York --- yes, Los Angeles --- yes, Chicago --- probably, Houston --- unlikely, and so on (I covered the top 4 most populous cities). My point is: a mass transit system will be unprofitable in almost all American cities or it would be inconvenient to use.

A case in point: it takes me >15 minutes to drive to the nearest DART station, which will take me to the downtown. It takes me 20-25 minutes to drive to the downtown in my car. Could you guess what I do? My DART line goes along 75, which has a speed limit of 60 MPH. DART cannot exceed 45 MPH and stops frequently. It takes more than 20 minutes to get to the downtown using DART. Like everybody else I pay my taxes to support DART (1% of all sales goes there) and like majority of locals I cannot use it.

  1. Any mass transit system sucks, if you need to travel with bags, packages, and stuff in general. Try to go shopping and bring back what you bought. Try to visit several stores during one trip. No matter what you do it is inconvenient.
  2. Mass transit is convenient, if the only thing you need is to haul yourself. If your commute to work takes >20 minutes, there are many things you can do to spend this time productively rather than being alert driving: reading, answering e-mails, working on laptop, and so on.
  3. There is one good alternative to a mass transit: a telecommute --- the most economical and efficient form of transportation. :-) As far as I can tell there are many lines of work, where it is appropriate and acceptable.
  4. A lot of public transportation advocates use European countries as an example. Usually they forget to mention that their price of gas is roughly twice higher than in U.S.A. because of excise taxes, which were designed to help European economy after WWII. ;-) It is one more example of punishment you mentioned.
# Eugene Lazutkin

I love the idea of PRT, but I have to agree with Eugene that there's not a lot of cities where it could cover its running and maintenance costs over more than a small area. Here in Sydney, Australia, a gigantic problem would be purchasing the real-estate for the stations and tracks.

Also, a nit: as nice as a complimentary car service would be, it's more accurate to describe I-GO as a "complementary" service.

# Alan Green

A PRT rail line is only supposed to take up one lane, and could be put into a parking lane, so the real estate is fairly limited. It's also compatible with other traffic, unlike LRT or some other systems. Elevated heavy rail is much harder, because they are so heavy; as a result no one seems to be building them anymore. Those take up a lot of real estate, probably the biggest cost for doing any expansion (especially a dense city); going underground of course has its own very high costs. Anyway, potentially you wouldn't need anymore land, and SkyWeb Express is estimating 13-24 million $US in installation costs per mile. That's more than I've seen elsewhere, but seems pretty affordable in comparison to other systems.

# Ian Bicking

I believe that PRT will be what cities will be using in the future. The "future" being 50-100 years. If you look at the numbers (cost per mile, capital costs, etc.), it just makes far too much sense. The reason PRT hasn't been done is that PRT hasn't been done: the transportation industry is incredibly conservative and awash with monied interests (at least in the US). All it will take is one success, and it should take off.

Look at it this way. If an average city put in a single PRT loop through the middle part of the city, and maybe a run out to an airport, do you think a shopping maul might be willing to through a few million to be added to the loop? How about an apartment complex? It scales the same way the Internet did.

Now, jumping to python here, if we want to help make this happen, the way to do it is to create a simulator where all someone has to do is put in a 3d view of a city and a track pattern, and then they should be able to virtually ride the new system. Multiple CPUs may be required :-). I seem to recall that google was doing a 3d capture of San Francisco a while back. I'm not sure how far that's gotten.

# Gary Godfrey

Someone actually made a graphical PRT simulator (maybe two?) in Python. But damned if I can find them. One was of a single station, and one was of a complete network (if I remember correctly). There's one listed here, but it's not the one I was thinking of.

There's work underway on a PRT system for Heathrow airport, and one in planning for Dubai. Hopefully those will work out well. At one point there was work on one for Chicago (O'Hare?), but the project didn't go well. My understanding is that the relationship between Raytheon and Taxi 2000 didn't go very well. Raytheon was looking to move out of defense (peace surplus, hah, remember those days?), and they were foisting decisions on Taxi 2000 (the PRT company that is now SkyWeb) that made the system bigger and un-PRT-like.

# Ian Bicking

Longer trains vs. more frequent trains is usually a result of old signalling systems that can't cope with higher frequency. I know this is the case here in Melbourne.

# Richard Jones

I figured something like that, but I still find it odd they would do what I believe comes to half a billion dollars of work to avoid upgrading their signalling systems. (Well, they are doing more than that in the upgrades, but it's still lame.)

# Ian Bicking

Well you've almost got it. I'd make a few changes. First, I'd do away with the rail and make the cars drive themselves on the existing roads. This gets rid if the big infrastructure building problem and makes the trip door to door. Sure cars can't drive themselves yet but they're getting there. They don't have to be perfect - just better than a human being. That's a pretty low standard to meet if you ask me.

Second, get rid of the fixed routes. When you need a ride, you punch a button on your GPS enabled cell phone and tell it where you want to go. A big server farm puts that data into the system and then matches you up with an existing car that's going to the same general area as you and that also has space available. Your ride gets selected out of the existing cloud of vehicles currently on the road.

You could do this now by using drivers until the self driven vehicles become available. To scale the system for rush hour, you let people use their existing cars in a dynamic carpool. They're instructed by the same cell phone on who to pick up on the way to and from work. For off ours, you keep a certain number of vehicles availble. You'd loose money on the off ours but it would be worth it because the system works best if you can eliminate the personal vehicles.

Cars cost a fortune. By using the existing infrastructure and eliminating the need for a personal car, you should be able to move more people much more cheaply than any existing system. The only problem would be writting the software that matches people up to the best car for their trip.

# Joe Goldthwaite

That's very much like the rail option, except at-grade. This works okay as long as the system is closed. That is, people are not allowed in the system. Being better than humans at working with humans is a nearly AI-complete problem. Judging, for instance, the intention of a biker or pedestrian at a crosswalk requires a subtle reading of body language. So, get rid of the humans and you are all set.

Of course, this kind of environment is being set up in many communities. Many suburbs are already human-hostile, with more and more "order" being imposed with special lanes, traffic signals, etc. But it doesn't appeal to me very much. The technology for that kind of automation is crazy hard.

A more modest -- but still far from implemented -- goal is cars that are automated on the highway. In this model you have a closed system -- special highway lanes -- that cars can reliably work in. The infrastructure costs are lower because it isn't a complete system, and relies on drivers for much of the driving (everywhere except the highway). It's incremental to a degree, because not everyone has to use those lanes, though the people that do will have to replace or upgrade their cars. There is an efficiency because the lanes are much higher capacity. In theory I think there is some energy saving, because cars might actually travel close enough together to decrease drag; though I'm not sure if that's actually significant. In some proposals the cars go quite fast (e.g., 80 or 90mph) which means significantly reduced mileage. One of PRT's potential advantages is not the raw speed (though some systems are designed for high speeds), but running at a consistent and efficient speed. This is good for efficiency. The low-hanging-fruit of energy efficiency vs. speed is to increase (or at least retain) average speed, while decreasing maximum speed. Automated car systems typically only increase maximum speed to increase average speed.

# Ian Bicking

Reading my own reply, I wonder how I kept typing "off ours" instead of "off hours". My "H" key seemed to be working ok everywhere else. Brain fart I guess.

Like I mentioned, you could use drivers until the vehicles could drive themselves. I pictured a system where independent drivers would purchase their own vehicle and join the driver network. They wouldn't have set routes but would get directed by the cell phone or other GPS enabled device to where they pick up and drop off passengers. The driver network would take care of all the billing. Individuals who work other jobs could join the driver network during rush hour to help pay their personal vehicle expenses. Drivers working at night when there's less demand would get paid more per passenger. Even though the network would loose money at night, it could make it up during the day but service would be available 24x7.

With the cell phones networked together with built-in GPS, the hardware is in place to do this now. The software to track that many vehicles and match up the passenger with the best car is the difficult part. I don't even know if it's possible but it would be interesting to build some sort of simulation just to get a feel about how hard it would be. I've wanted to work on it for a long time but I'm too busy and I'm really not bright enough to do that kind of work.

If you did get it working, the other problem would be getting people to use it. By nature, it works better with the highest volumes. If you've got 10,000 cars hooked up to the network, the chances of you finding a ride going the same route as you is a lot better than if you only have 500 cars. At 100,000 cars, you probably wouldn't have to wait long for a car and the car wouldn't have to make very many stops. To get higher participation, you have the government subsidize it for a while. Companies that offer carpool incentives could use that to encourage people.

In short the problems are both technical and political but it would be nice if someone could get it working. It could revolutionize transportation worldwide. Like you said, current mass transit doesn't work very well. Here in Phoenix Arizona, we're too spread out for any traditional mass transit to work. Here, you need a car.

# Joe Goldthwaite

What you describe is actually very reminiscent of the micro bus lines common in the developing world. Coincidentally, these are often actual VW Microbuses, driving on kind of ad hoc routes and picking people up. They don't take you to your exact destination, and there's no high-tech way to manage or get a pick up, but they are definitely a more decentralized kind of bus.

It's kind of weird, but the developing world seems to generally have much better public transportation. How buses can run at a profit with $0.50 (or less) fares, I don't quite understand. But for the most part they really do seem to do well without much government help (usually fuel is subsidized in some fashion, I think). Lower wages, certainly. And their maintenance is much less... thorough. And they drive fast. And they use old vehicles -- less capital costs. Still, kind of crazy they can make it work and profit. That said, here in the non-developing world taxis are expensive. They are actually taxed, not subsidized, and they don't pick people up in the same way, and they have higher capital costs. But I worry that there are basic economics that make them unpractical. Drivers and mechanics are paid more here. People expect a nicer riding experience. But maybe it isn't impossible, if done right and smart.

# Ian Bicking

Yeah. I guess people would have a hard time paying the actual cost but that's more of a perception problem. The system would have to be cheaper than owning your own car. People are paying the cost now it's just hidden in their existing budgets.

As a little exercise, I tried to figure out about what my current per-trip cost is for my 2001 Tundra pickup. It cost 18,000 so lets assume I can drive it for ten years so the yearly cost is about $1,800. During that time, I'll figure that regular maintenance will average $500 per year. I drive around 16,224 miles a year making six 52 mile round trips a week. I get about 18 miles per gallon so my yearly gas bill should be around $2000. I also pay about $1,200 in insurance. That comes out to a total of $5,500. I'm figuring on 312 commutes to work a year so every single time I drive to work and back it costs me about $17.62. I probably wouldn't pay $3 for a one way bus ride but I'll pay much more than that to drive without even knowing I'm doing it.

That's part of the political problem. You can create a system that's much more efficient because you increase the ride density. Put an average of four people in that car without adding too many miles to the trip and you greatly decrease the per-person cost. There are billions of dollars in potential savings! Plus, if you can get enough people using it, it decreases traffic which increases both fuel and time efficiency. In many places, it would speed up commute times because even though you're making more stops, you wouldn't be stuck in traffic.

Bootstrapping the system would be the hard part. If you can't get enough people to use it, it wouldn't work. The wait times would be too long. I have my doubts about whether you could ever get it up and running but if you could, it would be the only mass transit system that would work out here in the west.

In Russia (at least when I visited in 1995-96) there are "routed taxis" (marskrutnaya taksi) and "taxis". The routed taxis are vans and just take you to the nearest metro station. They fill the gaps in the streetcar/trolleybus/autobus network in the outer parts of the city.

The "taxis" are private cars, driven by people who need money or are just bored, so they drive around all night giving people lifts for maybe $3 a trip. People who don't want to be seen taking public transportation take "taxis" instead, and everybody uses them in the off-hours. You just hold out your hand (straight out, not thumb up) at the passing cars until one stops, and then negotiate a fare. I had friends who drove them occasionally. I wondered if they were safe but I never heard of anybody getting robbed in one.

# Mike Orr

I saw The Oil Drum article too -- quite interesting. I agree with you, mostly, and have been hoping PRT gets taken seriously. I do, however, have a couple of notes. (1) Chicago is not a good transit model, but Portland is. (2) Urban planning has to be holistic.

Chicago is not a model of efficiency, transparency, or modernity in its transit system. I don't mean to rag on your city, but it doesn't have a reputation for transparent governance or efficiency. $4 for a ride? That's crazy! Denver charges $1.50 and is rated as being the best public transit system in the country. But the real model for transit isn't Denver, because Denver has high city ridership but the suburbs are sprawling disasters. The American model city should be Portland.

Portland, and the state of Oregon, have taken an active role not only in containing sprawl, but pursuing a master plan that incorporates all aspects of city design. Building permits are not rubber-stamped -- they have to be part of the plan. Can you imagine if Python accepted every single patch that came its way, and there was a huge profit motive in patching Python? It'd be a disaster! And that's exactly how a lot of our cities happen. There's no plan or design, just approved building permits.

The city design, including the design of private property, has to be holistic. It has to incorporate transportation, recreation, shopping, open space preservation, and other aspects of city life. If you build a sidewalk along a wide street with strip-malls on each side, that doesn't encourage pedestrian traffic. It you build a "transit center" in a city with a population density of 400/sq2, that doesn't make it a transit city.

# ken kinder

BTW, it's $4 round trip, $2 one way. So Chicago is a little on the high end, but not at all abnormal.

Chicago's El infrastructure is certainly not representative of new construction. Much of it is -- as infrastructure goes -- pretty ancient. They started building it out 100 years ago, after all. I think New York and London have the same issues. Modern heavy rail/subway systems are much faster. The El in particular seems to be hard to maintain -- putting 20 ton cars on metal stilts is not very maintainable. Real upgrades take years of interrupted service, so that's not very feasible either. The result is a pretty slow train system. I think the Brown Line (one of the slowest) averages 15mph (including time at stations).

Chicago has crazy sprawl in the suburbs, but I'm not even considering them at this point -- there's still a very large urban area of Chicago of medium density that's not being well-served. I bring it up in part to shoot down another mass-transit-phile argument, that if you just had the right urban planning this would be easy. Chicago proper has planning that is amenable to mass transit, but it still doesn't work very well. We have a decent amount of bikers (by US standards) and lots of pedestrians, and lots of people that don't own cars. Everything other cities are trying to achieve. And it still doesn't work. There's no significant natural or manmade barriers to non-car traffic in the city, which is better than lots of places. But it still doesn't work. Box stores with parking lots in front have made up a sad amount of new development in Chicago, but most commercial space is still right on the sidewalk. We have 12k people per square mile. We have alleys, and we don't have many driveways crossing sidewalks. We have lots of one-way streets. Almost all our streets are multi-use -- shared and chaotic and cooperative. Chicago has most of the things that New Urbanists talk about. In a lot of ways Chicago is the best of a bad lot. But it still doesn't work!

Maybe if a city is just more clever it could work. Adding bike lanes on existing streets next to a parking lane doesn't make for a great bike lane. Building a less centralized set of trains would be better than the spokes we have. Public bathrooms downtown would be super. Sometimes the sidewalk is too narrow. Vehicle pollution is a real problem as a pedestrian; I wish we had better emission controls. Our parks, though generally well used, are mostly quite sterile, and others can be hard to get to, especially with public transit (since the nicer parks are on the edge of the city, and they aren't on the way to anything, so they get worse service).

But frankly I'm rather skeptical. I've heard lots of good things about Portland's planning and transit. But I still think we need something a bit more radical. I feel like a lot of the reaction against the suburbs is just reaction, just reactive, just trying to fight against something. I know what they are fighting for, too; but it's caught up in values and goals that can't be transferred, or are too hard to transfer, and too hard to get people to care about. But real functional improvements are much easier to express and convert people to than these vague values we have. The best planning isn't just pleasant, but it's inclusive and expansionist and functional and productive. Those are the defining attributes of America -- and the suburban style of planning has lived up to those things, as ugly and impersonal and wasteful as the result is.

# Ian Bicking

See my reply below about radical changes. Portland did a lot of things right. If you haven't been there it's quite an enjoyable experience. Not just the transit, but the little parks downtown, Powell's books, etc. The transit is cheap. The MAX light rail goes east, west, and north into the suburbs (and would have gone to Vancouver WA if they hadn't voted it down). The east line was the first, unfortunately it has way too many stops. But they built it in open woods in Gresham where they wanted development to occur, rather than letting sprawl happen and then having to take out businesses for it. But many people I know live in southeast Portland which has no MAX, and you have to wait half an hour for a bus on Sundays. This even though it's an inner-city neighborhood close to downtown.

Seattle has a better bus system, more frequent, almost 24 hours to the inner neighborhoods and the airport, and almost as cheap. But it's only buses. So if there's a baseball/football/basketball game or just an everyday accident, you'll be sitting still for a while. They are building light rail, and we almost had a monorail too but it was cancelled. (Not the 60s monorail; I mean one that residents could actually use.) The regional organization that's building the light rail, Sound Transit, refused to consider monorail or PRT because "light rail is the only system proven in the US, so it's the only system we can get a federal grant for". The monorail advocates said screw the federal funding, we'll build it ourselves. It would have covered the west side, where light rail was not slated.

It sounds like you've read Jane Jacobs (The Death and Life of Great American Cities); she was the first New Urbanist if you want to call it that, and has many good ideas about making cities human-scale even though she was writing in the 50s. Basically, things have to be "small". There can be a lot of small things over a large area, but no huge housing developments or lonely big buildings. Chicago... is partway there, but still has more "bigness" than it needs. I think it was Clark Street between Belmont and Fullerton that I felt that, near some big block-long stores. And Fullerton near Orchard Street; things felt a little more spread out and residential than they had to be. (I don't believe in pure residential areas.) I don't know about Chicago parks, but Jacobs points out that parks in general must be laid out for the convenience of the park user, not built arbitrarily to look pretty. So many parks have empty benches... because they're not in places where people want to sit. People want to watch other people, so benches near other people get well used. Plazas get well used for the same reason. Does Chicago have any central plazas? Those are rare in the US, but they're the things that could make the biggest difference in making a city "comfortable" if done right. But they have to be close to people's houses or wherever they would normally be anyway.

Transit suffers from the same problem: you have to start with what the riders want. Speed, frequency, comprehensiveness. Most transit systems fail on all three counts. Cities don't build what transit riders want; they build the minimum necessary to get the advocates to shut up. Or they delude themselves that one light rail line will solve everybody's transit needs.

# Mike Orr

While I mostly agree with what you say, existing mass transit tends to be not much better than cars, I have to take issue with this statement:

A highway lane of car traffic transports far more people than a single rail line.

I don't think this is in any meaningful way true. Typical theoretical rail capacity per unit land area is 5-10 times that of human piloted highway systems. While Chicago has far more auto commuters than rail commuters, it also has vastly more highway lanes than rail lines.

It's certainly true that the El doesn't use its capacity particularly well, but I believe its throughput were unit area is still much better than the highway system, especially at rush hour.

This is one of the less discussed benefits of transit, the Car Free Cities folks are big into the benefits of lowering transportation footprint for density and overall livability, I think they have a reasonable point.

With that said, I'm all for better systems than light rail. :)

# Jeffrey Harris

A highway lane of car traffic transports far more people than a single rail line.

I don't think this is in any meaningful way true. Typical theoretical rail capacity per unit land area is 5-10 times that of human piloted highway systems.

I thought I read something about this somewhere... but now that I think about it, it doesn't make sense to me. I'll correct that. This report seems to cover the issue of rail capacity (looks interesting; I should probably read it more closely). It seems to say 15k-50k passengers/hr of capacity, depending on vehicle type and train length. Reversing the numbers on this page imply that a highway lane has a capacity of 1.5-1.7k. So yeah, I'm just totally wrong.

# Ian Bicking

The main problem is that cities in the US weren't designed so people could live within walking distance of work and the store and nightclubs and the like. Then people wouldn't need much transportation. A few older neighborhoods are walkable, and -- surprise, surprise -- these happen to be the most desirable addresses and have the highest real-estate value. You'd think the zoning regulators would get a clue and build more neighborhoods like that, enough to saturate the demand and bring the prices down. Especially since people in those neighborhoods use half as much energy per capita as others.

The automobile is so dead. The game is up not when the last drop of oil is used, but when half of it is used. Then the price will rise significantly and rapidly. There's disagreement in the oil industry on when it will occur, but David Goldstein (Out of Gas: the End of the Age of Oil) argues it could come in four years. All the 30-year predictions fail to account for the ever-increasing demand in China and India, and assume the US level will remain steady and not increase (fat chance). Some other countries have good public transportation and walkable cities to fall back on, but the US has pissed away most of its opportunities. This should really worry us. A terror attack is nothing compared to a 15-year depression until alternative-fuel cars become viable on a mass scale. What's going to happen when 80% of Americans can't get to work because they can't afford gas for their SUV, and the public transit line that would have taken them to work was never built?

Low-volume cars really are the problem. See all the empty space around the person that's taken up by the vehicle. Feel the weight of the vehicle, how much power is required to move it. I've heard a double-length bus gets three miles a gallon. At that rate you only need twelve people to compensate for a 36 MPG car -- and the bus has room for forty more people, all within three car lengths. The reason there's traffic congestion is the planners won't dare to build a system that would really accommodate 1.2 cars per person. You'd need freeways a mile apart, and parking lots significantly larger than our current ones. That was already recognized in the 50s, and the freeways were proposed, but even the most freeway-happy cities won't swallow that much roadway. Now several cities including Phoenix and my hometown Seattle are slated to get a million more people in the next twenty years. One extra freeway and a few park and rides won't be enough.

Good public transportation has to be faster than a car, come every five minutes including evenings and Sundays, and cover all portions of the city. Places that do this, like Moscow, London, and NYC, find a significant number of residents don't need cars or want cars. It can be done in small cities too: Germany is doing it. Duesseldorf and even Bielefeld have streetcars that go underground downtown, Duesseldorf has a train station right at the airport that links to any city in Germany, and a 24-hour commuter train to Cologne and Essen. AND comprehensive night buses, at least on Friday and Saturday, so you can get home from the bar without driving.

Unfortunately, so many cities think they can just do one light rail line and that's enough. It's enough if your house, job, and evening activities are all near the line. Otherwise you're stuck in traffic, have to pay insurance on a car, etc. Try three lines or maybe six, and then you'll see half the residents ditch their cars. But it has to be in a grid, not an octapus like the Chicago EL. If Chicago had a half circle connecting all the lines, usage would more than double because there would be many more one- and two-segment trips possible without going downtown and back. Note that a grid (which need not be rectangular or uniform) is similar to PRT loops, although larger. The PRT articles I read said it's not suitable for very large cities like Chicago. The large numbers of people would overwhelm it. But it could complement the El or Metra in outer neighborhoods or suburbs. Seattle (500,000) is considered a good size for PRT.

Chicago and NYC may suck, but they're more convenient than anywhere else in the US if you don't have or don't want a car. Although it's sad Chicago is just letting the infrastructure deteriorate. Why don't they modernize the tracks and use rubber-tired cars so the El wouldn't be so painstakingly slow and loud? I remember sitting in an almost-empty train car at rush hour and being baffled. In DC the metro is full even at 10:30pm.

Decentralized paths is a good point in general. Inner cities are less congested because they have grid streets, so there are several paths to anywhere and each person chooses a different one, and they can detour if there's a bottleneck. But suburban neighborhoods often have only one road going in and out of them, with dead-end streets and cul-de-sacs off it. These get significantly more congestion. I'm not sure decentralized paths is feasable with transit, however.

What's this about light rail using more BTU than cars or buses? That sounds highly suspicious. Five vehicles chained together use less energy than five separate vehicles, and the tracks should provide less resistance than the roads.

# Mike Orr

The PRT articles I read said it's not suitable for very large cities like Chicago. The large numbers of people would overwhelm it.

I think PRT people undersell it, sometimes for dumb reasons. They still want the mass transit people to like PRT. The die-hard mass transit people can't stand PRT it seems. They love the idea of mass transit. The biggest critics of PRT are mass transit people; they are tedious but incredibly consistent. Hell, I hear Ken Avidor is even trolling Seattle discussions now (he's been a long time Minneapolis troll).

Everything I've seen indicates that PRT can support more throughput for less infrastructure cost, and with less right of way than any mass transit system. Maybe NYC subways pay off better, but NYC has a unique level of ridership (at least in the US). So, putting aside New York, I think PRT has more potential than any other system, regardless of density. If the infrastructure costs are lower, and the experience is better, and the operational costs are lower, then density shouldn't be a problem. It just means you get an even better level of service as the system is built more densely.

That doesn't mean Chicago is the right first location for PRT. It would be an excellent first location -- I'd be delighted of course -- but there are other places more desperate for new kinds of transportation, and without any real alternatives. In those locations PRT isn't just a better choice, but maybe the only real opportunity for a solution.

What's this about light rail using more BTU than cars or buses? That sounds highly suspicious. Five vehicles chained together use less energy than five separate vehicles, and the tracks should provide less resistance than the roads.

This page lists energy for several systems. It actually puts a bus as on par with light rail, and both above cars. Generally speaking, this applies to a non-commuter system -- i.e., one that doesn't just carry a consistent (and high) level of commuter traffic, but also provides service at non-peak times.

Also, light rail is really really heavy. I'd guess that pound-per-passenger it's on par with a car.

Remember also that this is BTU per real passenger mile. Real trains aren't full all the time. They get less full as they reach their terminal point. There is directional traffic, so they are full in one direction and empty in the other. There is varying usage at different times of the day, and you can't get smaller than one car. So all of these numbers are based on the actual ridership seen in real systems. And the nature of mass transit is it can never provide good service while consistently running anywhere close to capacity -- it's just structurally impossible for those systems.

Lastly, five cars isn't that much more efficient. Amount of stopping and starting and the weight of the vehicle mostly determines the fuel efficiency. So five cars isn't that much more efficient than one. And they are just crazy heavy, and they stop and start all the time.

Current PRT systems aren't actually that much lighter than a car (though it's an immature technology and so I would certainly expect systems to get dramatically lighter). I think most designs have 1 ton cars. The advantages are that they travel slower, stop and start less, and operate only on demand. The energy efficiency is partly in the freedom you get in a lighter, simpler, more modern system; but most of the efficiency is in the basic design of the system, the non-mass aspect.

# Ian Bicking

The PRT articles I read said it's not suitable for very large cities like Chicago. The large numbers of people would overwhelm it.

I think PRT people undersell it, sometimes for dumb reasons. They still want the mass transit people to like PRT. The die-hard mass transit people can't stand PRT it seems. They love the idea of mass transit. The biggest critics of PRT are mass transit people; they are tedious but incredibly consistent. Hell, I hear Ken Avidor is even trolling Seattle discussions now (he's been a long time Minneapolis troll).

I was wondering who Ken Avidor is, but he seems to have answered it himself (below).

I'm not against PRT. It's just that we just finished a 10-year debate on light rail vs monorail vs PRT vs more buses, and the worst choice won. A light rail that has traffic crossings in two sections, and whose first phase is not where the bulk of population is. But I learned that in order to get anything done, you have to get everybody to agree, or at least enough of the movers and shakers. That's the problem with PRT. Not that it's intrinsically bad, just that it gets laughed off the table. Nobody wants to commit millions of dollars to be the guinea pig. We got the same complaints about monorail but were able to point to working systems in Japan, Malaysia, and Las Vegas. I would like to see PRT tried citywide somewhere, and Joe who suggested Phoenix may be onto something. Nobody has been able to find a better solution for post-WWII automobile cities, so PRT could be it. But it would take a very forward-looking city to consider it, with much risk.

The capacity argument was specifically directed at London and Los Angeles, saying that PRT could not handle hundreds of thousands of people going downtown all at once. I assumed Chicago was the same size and dynamic, but you know more about it than I do. PRT is like an elevator system or supermarket check-out line. It works excellent when under capacity, but deteriorates rapidly when it reaches capacity. So PRT complements a trunk system rather than replacing it, and would work in individual neighborhoods or districts or medium/small cities (including most of the US). PRT is good if there are five or ten people at a stop, but not for clearing out a baseball game.

# Mike Orr

I agree that traditional transit activists have had an effect on the way that PRT is sold. PRT proponents now tend to shy away from pushing PRT as a replacement for traditional transit.

The problem, it seems, is that traditional rail activists fought back hard, and dirty. A lot of them (Avidor in particular) have resorted to outright lies and scare tactics in their propaganda campaign. So I think that caused PRT proponents to back off the assertion that PRT could replace most rail systems.

I certainly don't think it's a technical limitation. From what I've seen, a mature PRT system could easily serve a large city like Chicago, assuming of course it was extensive enough to cover the whole city. Don't forget, when you look at cities like Chicago and New York, you are comparing PRT to existing systems that would probably cost trillions of dollars to construct in today's network. With that kind of money, a monstrous PRT network could be built, and well-designed PRT scales better than any other form of transit because of the network effect.

So I think the stated PRT limitations are motivated more by political concerns than technological ones.

# A Transportation Enthusiast

Hmm. Are you sure that rail infrastructure is more expensive to maintain than road infrastructure? I always heard the opposite.

The problem is, as you say, that the road network is packet-switched whereas rail is closer to circuit-switching. Rail needs a lot more flexibility. Plus the rail network is harder to upgrade on an ad-hoc, piecemeal basis than the road network.

A couple more suggestions for upgrading the rail network :

# phil jones

A view from a different kind of city can be interesting.

In Bologna, like in most Italian cities, excessive car use is causing serious air pollution. Most streets are too narrow for fancy transport systems and reserved lanes; parking a car is expensive (in private garages or underground parking lots), or difficult, or illegal, and usually inconveniently distant from one's destination; digging a subway is out of the question.

The main parts of the city center are closed to private traffic (except for residents), with automatic license plate recognition from surveillance cameras. This automated fining system has been kept turned off for years and its startup last year has caused a lot of income for the city but an insufficient reduction of traffic; illegitimate travelers persist and legitimate travelers are still too many.

Public transport consists of buses, of which only a small minority are electrical, and frequent trains to nearby towns. Buses are highly undependable: often very late or missing due to traffic, frequently diverted without warning and with complex variants of each line.

Both suburban trains and buses stop very early in the evening, turning off many potential users. For example, the Bologna-Vignola railway has a stop very near the large basketball court in Casalecchio (about 10 km away); the last train back to Bologna leaves well before the start of evening games or pop concerts.

The only improvements would be brutal restrictions to polluting traffic (but these people vote...) and budget increases to have more buses on the (now less cramped) streets. It is not a matter of low volume or low value traffic: every single car in the city center, either moving or parked, is a problem by itself; with few exceptions it shouldn't be there and its driver is a lazy asshole.

Instead, following the immortal public policy principle of spending money now and solving problems later, a largely redundant "light" rail system between the airport and the central train station is being planned.

# Lorenzo Gatti

One other problem with mass-transit and children. You have no control over the environment they are going to be exposed to. For all you know you are going to end up on a bus or train with people swearing, talking about who knows what, or be subjected to some less than appropriate advertising.

# Nathan

Unless you're home-schooling your kids, you don't have that much control over their environment. If it's not some random person on a bus, then it'll be their friends at school. Either way, they're going to be exposed to less than appropriate material.

# Blake Winton

There's been a lot of mention of New York City in this thread, but so far AFAICT no comments from anybody who actually lives here, so I thought I'd chime in.

New York does some things right


p.s. Ian, you might want to rethink the idea of having bus drivers be more aggressive. Have you ever ridden a jam-packed bus, being forced to stand up and trying not to crush / get crushed by your neighbors while the driver alternates stomping on the accelerator and the brakes? It's pretty tiring, even nauseating at times.

Why mass transit in NYC is still massively better than owning a car

At some point it occurred to me that the money I spent on insurance, parking, and maintenance was a lot more than I'd spend if I got an occasional taxi or car service and the occasional weekend or half-day car rental. So I do that, and I joined Zipcar ( http://www.zipcar.com/ ) (much like Flexcar or IGO). Haven't regretted it at all. There are now several zipcars parked literally around the block from my house.

# Paul Winkler

I live in Manchester, a UK city with about 2.5 million people, the first industrial city. Pretty much all transport seems to suck here (unless you are close to a main line rail station). They are slowly rebuilding the metrolink tram network, but it is closer to a light rail network than a tram (streecar) network. The trams used to go everywhere, until they pulled up the rails 50 or more years ago (or just tarmacced over them). Trams are pleaseant and reliable compared to buses. We need many more of them. Whenever I go to cities in europe, especially eastern europe, they still have extensive urban tram networks, it makes getting around so easy. Perhaps the best public transport I have found has been in Vienna, where there is a good tram network combined with a good underground network.

In the end though I'm disorganised so I need to get everywhere by the quickest possible means of transport, which in the city means by bike. I live in hope that one day the city council will realize that cycle lanes on the pavement (pedestrian bit - sidewalk?) are completely useless and just paint lanes on the road.

# Laurence Rowe





This is a resolution opposing PRT funding from Transit for Livable Communities. The Sierra Club Northstar has a similar resolution:

http://www.tlcminnesota.org/Events/2004/Legislature/ No%20public%20funding%20for%20PRT.pdf

Op Ed about PRT in the Seattle Post Intellligencer about PRT:


This article explains why PRT is infeasible from an engineering perspective- Cyberspace Dream Keeps Colliding With Reality


The Road Less Traveled: The pros and cons of personal rapid transit. " by Troy Pieper


PRT skeptic site:


PRT is totally bogus.

# Avidor

Ken Avidor is an anti-PRT extremist. He spends much of his free time searching for PRT discussions and inserting links to his anti-PRT propaganda pages. He also seems to be trying to increase his Google profile by spreading his links all over the place, so when you search on PRT, you get his pages near the top.

For a more balanced treatment of PRT, see the Wikipedia page: http://en.wikipedia.org/wiki/Personal_rapid_transit

# A Transportation Enthusiast

Speaking of extreme....


Seriously, who is going to cut down half the trees on thier block for an elevated structure with a clear view into their bedroom windows?

PRT is going nowhere... click on the news at Taxi 2000/Skyweb Express... nothing new for over a year.

It's still a handy tool for right-wingers like Mark Olson and Michele Bachmann to bash transit.

Why are you helping Mark Olson and Michele Bachmann get elected?

# Avidor

Just so everyone knows...

Now that Avidor's found this discussion, he will post his entire propaganda spiel, one message at a time. He is obsessive about preventing anyone from having a reasonable discussion of this technology.

In this last comment (above), he alludes to his oft-repeated contention that PRT supporters promote radical right wing politicians. He logic goes something like this: some two-bit local conservative politicians in Minnesota happen to support PRT, therefore all PRT supporters are promoting the right wing agenda!

This is the level of analysis you get from the likes of Avidor.

By the way, the link he posts is from a well-publicized battle on the Wikipedia PRT article. We had to defend that article from relentless attacks by Avidor, and the defense got heated at times. Avidor wanted to kill the whole article because he can't stand the thought of a logical, reasonable presentation of the very thing he is trying to smear.

The Wikipedia page (http://en.wikipedia.org/wiki/Personal_rapid_transit) is how I discovered Avidor's tactics, and the depths to which he will go to spread his misinformation campaign.

You can get a blow-by-blow account of Avidor's attempted attack at http://en.wikipedia.org/wiki/Talk:Personal_rapid_transit#This_article_is_totally_biased_and_inaccurate

Note that, despite his month-long attack, not a single substantive fact was changed in that article. Avidor tried to turn Wikipedia into a vehicle for his propaganda, but failed miserably because his arguments are nothing but lies and scare tactics.

# A Transportation Enthusiast

There are serious problems implementing PRT systems, both technically and politically. PRT or Personal Rapid Transit is a set of autonomous on demand vehicles on a track or guideway. No systems to transport people have been implemented in 40+ years. One large scale system was a complete failure, the Denver Airport Luggage Handling system, a PRT for suitcases, which was operated by United Airlines.

The system had hundreds of millions of public money, 20+ miles of track, thousands of autonomous vehicles, hundreds of destination points built to handle all luggage at Denver in a new airport. Never worked, only United Airlines used a small portion to move luggage from the counters to a human operated luggage area. United shut the luggage eater down last year due to high operating costs and as a final insult, the $186 million of PRT system debt was dumped on the public in December 2005 as United Airlines went bankrupt.

Civil engineers and state-county-city politicians are well aware of the fiasco. Indeed, many studies of this engineering cockup by MIT, etc were done, check google for references. The usual reply to this failure is that "it is not REAL PRT." Like, duh, suitcases are not people and computers are somehow "better" now. This argument is weak and now PRT is widely known as "faith based transit".

Another fallacy cited by PRT boosters is comparing it to "packet switching" networks as if a pod of people are a tcp/ip packet going through a router. This has some problem as "packet switching" has collision rates and methods to over come high collision rates of packets. I think the tolerance of the public for even low collision rates of pods would be nil so this packet switching analogy is not such a good description. Applying network theory and algorithms to human systems is interesting but easier with a "social network" rather than a transportation network.

# George Jetson

I left out a word above, it should be: " computer programmers are somehow better now. " Which they are not.

"George Jetson" has been active recently in spreading the ridiculous "Denver baggage failed, therefore PRT will fail" propaganda message. He has posted elsewhere as "John Denver's Ghost", "Joe 8pack", "Joe 12pack".

He claims he is not Avidor, but his message is the same. No coherent arguments, just scare tactics.

He would have us believe that the Denver baggage system failure is proof that no automated system can work. It's a technophobic argument that doesn't acknowledge the fact that the Denver fiasco was just plain bad engineering -- something that can be corrected -- and not some fundamental technological limitation.

Besides, if we're talking about purely automated systems, Morgantown "PRT" has been operating for 30 years now, completely automated. Now, Morgantown is not true PRT (it's classified as "group rapid transit") but it is a fully automated human transport system. And as long as people are bringing up the Denver baggage system to bash PRT, well Morgantown is much closer to PRT than the Denver baggage system, and Morgantown WORKS.

It also appears that Mr. Jetson is trying to insinuate that computer network "collisions" would directly translate into PRT "collisions". It's another blatant scare tactic.

Arguments like this might sound ridiculous to anyone with a technical background, but these tactics do have an effect on the general public -- people who don't know better might think that PRT designers are actually designing for collisions! That's why people like Avidor (and Jetson, if indeed he's a different person) must be answered wherever they appear. If their absurd message goes unchallenged, it has a better chance of being accepted by the masses.

'widely known as "faith based transit" '?

Google this: "faith based transit" prt

There are 14 hits. Is this how you define "widely"?

# Skeptic skeptic

Not only that, all instances of the term lead back to the same one or two people. It's unclear if it actually is a couple people (like killbill and George Jetson), or just one person (Ken Avidor) under different names.

# Ian Bicking

In order to evaluate transport methods one must factor in all costs. That is notoriously difficult to do, mostly because proponents of cars (eg: capitalist / feudal organisations like Ford et. al.) prefer to bury the truth, lobby governments for free resources, and lie all the way to the bank.

Why did early mass transit systems in America fail?

Answer: They didn't. They were entirely successful until car companies bought them up and bankrupted them.

Why do cars look like a good mode of transport?

Answer: Because all the costs of roads, environmental pollution, fuel subsidies and so on are born by the regular taxpayer. The capital costs of rail (for example) are seen as too expensive while far greater amounts of money are spent on cars.

Ivan Illich showed the true cost of the bicycle makes it the most efficient mode of transport. Mass transit is less so, and cars are the worst offenders.

Mass transit is not acceptable because people have been duped into associating cars with "freedom". But the mass murder caused by these vehicles is apparently acceptable in the name of capitalism.

# robin

Well, mass transit is one of the largest corporations which need a lot of money to keep on going, and where they get all that money from, well our taxes obviously.

# Niki

My name is Harold Leese and in a few weeks, I will be losing the public bus service I have largely due to state budget cuts to our cities. I rely on a car because I work 24 hours a day, 7 days a week on a call basis. I tried to stop the busses from shutting down by trying to stop the state transit cuts and working with transit officials to get more riders, but leaders claim that taxes on fuel no longer work and transit advocate groups will not fight back.

In addition, state and regional leaders will not work to make small improvements that would get more riders and make transit taxes work better. I know very well that mass in Detroit and inner suburbs can work very well if we can just improve what we have. Please comment on my mass transit website at http://www.savethefueltax.org

# Harold Leese

That is a really cool and useful article! Thanks... i think Personal Rapid Transit -is a future of mass transit..

# Alex

yes i've just read the hole article and whole comentaries - and it's really intresting thanks for this 2 u all - i have to absolutely agree with you guys

# John Praca

Keep up the good work. Greetings

# Pozycjonowanie

Your are leaving out one new PRT transit: autonomus vehicles (no central system control=high speed) + required examinations. Google Hallitubes. Supported by researchers at major universities.

# Chris

Hi, tell me please, where i can find some information obout Danish Mass Transit?

# Andy Mcnill

A very interesting site, I think. The Idea of Technology was new for me but worth to be read and thought abot it (although I'm not a native english-speaker and have some difficulties whith this language)

# Thermage

A very interesting site, :)

# gry

Hello Ian, I've met you in PyCon before. But I don't know you have a passion in transit system too. I completely agree with you on most points in your original post. Let me contribute a little in this discussion.

I think I am qualified as a public transit advocate and anti-car person. My main commute is heavy rail + bike. It takes about 45 minutes door to door one way, or a little more than double compares to car. This is a huge improvement compare to my previous job that required an over 2 hour one way commute by rail. I also own a car and use it a lot to transport my family of three. Given I have only one car between two adults I can still claim my car ownership is 50% below norm.

While San Francisco is credited as having one of the best transit networks in US west coast, if you ask me to rate it, I say it SUCKS. Besides all the reasons you have articulated, an additional problem in San Francisco is politics. The buses travel at snail speed because they often have stops at every street corner. So every time a rational person sees this problem and proposes 'Hey, we can speed things up if we just change the stop to every two street corner!' Always some activists would come up in arms in opposition, citing it will do much harm to the elderly/disabled/poor people. OK, so no change. The entire city shall go at the same pace as the elderly/disabled/poor people.

I too see PRT as public transit's future. As a technology person, when I first learned about PRT, I immediately recognized it as a paradigm shifting idea, an automatic transport system that perform as well as or better than private cars. Being a public transit advocate, one must first eschew the ideology that car is bad, transit is good. Only then can we understanding the performance difference between a point-to-point transport system v.s. fixed-route transit and find a better way forward.

Another reason I am passionate about PRT is from a humanist perspective. It is very sad to see many traffic accident happens from the convolution of cars, bike and people. People make bad judgments, often putting speed ahead of safety. It is much better to take this risky task away from human hand and replace with an automatic system. Years later when all transports become robotic, we will look back and think how barbaric driving used to be.

# Wai Yip Tung