A Next Step for Autonomous Buses?

Photo: David Wheatley

A fully autonomous bus is now in regular service in Scotland.  It still has employees, two in fact.  But if this technology works out, the ultimate goal is probably to run buses with no employees on board. In wealthy countries, the cost of running a bus is mostly the cost of the driver, so in theory, if and when all the bugs are worked out, a driverless bus could be far more abundant, for a given operating budget, than buses with human drivers can be.

That will be wildly controversial. I have mixed feelings about it. But driverless rail transit has existed for decades, starting in Vancouver in 1985. The lack of a driver is why trains in Vancouver come every few minutes even late at night. In emergencies people like for there to be someone in charge, but the voices coming over the intercom from headquarters often have a better picture of the situation than an on-board employee does. Driverless buses would definitely be part of a world where security is based more on electronic surveillance, and like many people I have mixed feelings about that.

But if we end up in a world with abundant and affordable autonomous taxis — still a big if — it will be very hard for cities to function without autonomous buses. When we remove the hassle of traveling by private vehicle, and reduce the cost, everyone will want to do it, and a city simply doesn’t have room for that.  The only other solution will be heavy decongestion pricing to make the affordable autonomous taxis less affordable, and/or bus lanes on every street so that buses effectively bypass autonomous-taxi congestion.  That may be the answer, but in the long run I’d rather see public transit be abundant, so that everyone can go places quickly in a space-efficient way.

I Am Not a Bus Advocate

What, you say?  But you wrote an article in the Atlantic called The Bus is Still Best!  You redesign bus networks for a living!  You’ve been a skeptic about all kinds of new alternatives to the bus, from monorails to streetcars-stuck-in-traffic t0 “microtransit.”  Have you changed your mind?  

I am a freedom advocate[1], which means that I like it when people can go places, and therefore do things, and therefore have better lives more rich with choice and opportunity.  And when I analyze how to deliver freedom cost-effectively, the fixed route bus turns out to be the right answer in a huge percentage of cases.  It’s not right in all cases, and where it isn’t I don’t recommend it.  (Where a community has other goals, that too can yield a different answer, which is fine.  It’s their community.)

But it’s increasingly common to read things like this

Entrenched beliefs that the bus or rail is best, period — and that ridership and scalability are all that matter — stop us from seeing all the places where we can leverage technology and new ideas.

[UPDATE:  This article has since been revised in response to my objections.]

The word “bus” was a link to my Atlantic article, whose headline, “The Bus Is Still Best,” I dislike but could not control.[2]  The implication of this link is that I am “entrenched” in an emotional attachment to buses the way that many people can be emotionally attached to trains or airplanes or Porsches or whatever.[3]

Such attachments may also just be financial interests.  For example, huge amounts of venture capital are being spent making it sound like microtransit is a world-changing idea, and to attack those of us who honestly can’t make mathematical sense of that claim as being rigid, stuck in our ways, “entrenched.”[4]

In fact, I feel no emotions about transport technologies.  My shelves are not full of cardboard model buses.[5]  And where the right answer to the problem of efficiently providing freedom isn’t a bus, I don’t recommend a bus.  I have recommended all kinds of technologies in different situations. I want to achieve goals, and I look for tools that do that in each situation.

Above all, I hope I’m known for suggesting that our thinking should start with goals rather than emotional excitement about technologies, and that this requires some serious effort, because every technology salesperson wants us to do the opposite: first, get excited about a technology, then try to come with a goal that could justify it.  As soon as “innovation” becomes a goal in itself rather than a tool, we are headed down that slippery slope.

So I’m not surprised that I get attacked now and then, and now here’s a post as a ready-made response.  Next time you see someone say that I am (or you are) a “bus advocate,” or “entrenched,” just send them a link to this.  Thank you!



[1] Or, if you prefer, an access advocate.

[2] Never, ever link to something based only on the headline!  Headlines express the attitudes of the publication, not the writer.  (I am slapping my own wrist as I write this, because I’ve been guilty too.)

[3] … which is not to criticize emotional attachments.  I have them too about many things. As always, I am describing myself, not judging you!

[4]  This assumption about financial interest also gets projected onto me sometimes, so for the record: I have no financial link with any bus manufacturer, bus operating company, etc.

[5] … though if yours are, that’s wonderful!  As always, I am describing myself, not judging you!

The Chinese Straddle Bus Exists! What Now?


The Chinese straddle bus has now been built, and run on a test track!  Whee! Here’s the gee-whiz video.

As I said before, I think that especially in wealthy countries, this thing is mostly useful as a parable, whose message is:  Look how much money people will spend on infrastructure whose sole purpose is to avoid taking any space from motorists.

If the thing has any application, it’s probably not in Europe or North America, because:

  • It’s massively capital intensive.  The little rail-like running-ways in the street are the least of it, and the fleet is the second-least.   The stations must be massive elevated structures, with a mezzanine above the top of the bus.  Existing bridges would almost all need to be raised.   Countries with high construction costs will find this a barrier.
  • It will serve stations located on expressways, which tend to be bad places for the pedestrians that the bus will attract and disgorge.  The only solution to this is massive grade separation, leading to a continuous pedestrian plane at the station level, well above the street.  This leads to urban design that essentially abandons the ground plane to cars and rebuilds an entire pedestrian city above it.
  • The vast raised pedestrian plane was a hot idea for about 15 minutes in the 1970s, giving us London’s Barbican, Paris’s La Défense, Los Angeles’s Bunker Hill, etc etc.  Today, most European and North American urbanists hate these places and insist on solving problems on the ground plane, though of course the pendulum could swing again.  But it’s much more common and accepted in East Asia, and to some extent in former Soviet countries.
  • There’s also the problem that if you build this thing in an existing dense city, you are building it right outside of someone’s window.  So you probably need a political structure that can make and enforce highly controversial decisions, as opposed to the kind of deference to public protest that prevails in most Western democracies.
  • You really have to redesign big districts around this thing, which is another big barrier unless we are talking about entirely new areas.  A high pedestrian plane only works if the idea is shared by many surrounding buildings.
  • Where this thing connects with underground subway lines, your mezzanine for this elevated thing is at least four stories away from the subway’s mezzanine.   This requires high-volume vertical circulation, which no inventor has ever really cracked.  Elevators are really inefficient at high volume, and escalators are really slow at it.
  • The nature of this technology makes it hard to demonstrate at the right scale.  There is a basic conflict between “huge capital expenditure” and “demonstration of new technology.”  It’s the same problem that monorails and maglevs and “Personal Rapid Transit” and many other cool ideas have had.  Inventors need places to do demo projects.  But it’s not smart for a city to agree to be Version 1.0 of something, while also spending billions on the assumption of its permanent success.  This is how cities end up with stranded transit assets that can become net barriers to good transit (see Scarborough RT, Toronto, or the airport maglev in Shanghai, etc etc.)

(Update: In the third top-level comment below, Brian Smith points out that the surface space this thing takes is still wider than a bus lane, so why not just do aa busway?  He also points out that the vehicle is rigid and the test track was straight.  What happens when it goes around curves?   It takes more horizontal space of course.  And it seems to rely on a ground-level third-rail, which is considered wildly unsafe in the business.)

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

Does the History of a Technology Matter?


Mater Hill busway station, Brisbane

Ben Ross has a nice long read in Dissent about the history of Bus Rapid Transit, noting all the ways it’s succeeded, failed, and been co-opted by various non-transit agendas.  He’s especially interested in the way various petroleum-and-asphalt interest groups have supported BRT as an alternative to rail for reasons that probably don’t have much to do with their love of great public transit.  All this is worth reading and knowing about.

But what, exactly, should we do with this history?  Practically everything that breaks through into the public discourse has private public relations money behind it, and that money always has different goals than you and your city do.  That’s why you should always lean into the wind when reading tech media.  But just as it’s wrong to fall for everything you read in corporate press releases, it’s also wrong to reflexively fall against them.  (Cynicism, remember, is consent.)

Galileo paid the bills, in part, by helping the military aim cannonballs correctly.  Does that mean pacifists should resist his insight that Jupiter has moons?

So while I loved Ross’s tour of the history, I reject his dismissive conclusion:

Buses will always be an essential part of public transit. Upgrading them serves urbanism, the environment, and social equity. But a better bus is not a train, and bus rapid transit promoters lead astray when they pretend otherwise. At its worst, BRT can be a Trojan horse for highway building. Even at its best, it is a technocratic solution to a fundamentally political problem.

The term technocratic is really loaded here.  Given the new “revolt against experts” trend in our politics, we urgently need to recognize  hard-earned expertise and to distinguish it from elite selfishness, but technocrat is a slur designed to confuse the two.


RBWH busway station, Brisbane

There are some great bus rapid transit systems out there, and not just in the developing world.  The mixed motives that underlie BRT advocacy don’t tell us anything about where BRT makes sense, any more than the mixed motives behind rail advocacy do.

A light reading of history can help you recognize the prejudices that may lay behind advocacy on all sides.  But then you have to set that aside, and think for yourself.


Portland: Frequent Bus Performance Approaching Light Rail’s

Here's an interesting chart:

Tri Met Ops Cost per Ride

This is a year's trend comparing bus and light rail (MAX) service in Portland's transit agency, TriMet, from the performance dashboard at the TriMet Transparency and Accountability Center webpage.  

The metric here is operating cost per boarding ride.  This is a good overall measure of how effectively a transit agency is liberating and moving people, where down means good.  (I prefer this ratio upside down: ridership per unit cost or "bang for buck," so that up means good. but this is obviously a chart by finance people who always want cost on top.)  This is a "macro" metric.  Practically everything a transit agency does affects it, so it's lousy diagnosis but not bad if you only have bandwidth to convey one measure.

Most American transit data just compares bus and rail, and inevitably shows bus performing worse.  You'll see that here too if you just look at the wide solid lines.  From this we get endless ignorant journalism lamenting the poor performance of the city bus, as though all city buses are basically alike.

What if we separated out highly useful and liberating bus service as a separate category?  That isn't exactly the distinction made here but it's close.  TriMet's Frequent Service network (still being restored, but mostly now back in existence) is the network of all services that are almost always coming soon.  

This chart says two remarkable things:

  • Frequent bus performance is now very close to light rail performance.   
  • The spread between Frequent Bus and infrequent bus is usually bigger than the spread between all buses and light rail.

The lesson is pretty clear:  The "city bus" is a misleading category, and the much-fetishized difference between bus and rail may matter less than whether the services are designed to be useful.  And when it comes to usefulness, no one variable capture that more than frequency.  

Transitmix continues its development

By Evan Landman. 

Last summer, we covered an exciting new transit planning tool called Transitmix. Transitmix grew out of a Code for America project that sought to create a web-based tool to automate much of the complex yet mundane work that goes on in the background during transit planning. Cost estimation, line measurement, population and employment coverage analysis, are all examples of tasks that require time and effort such that they cannot all be carried out in real time during a planning meeting or workshop.

The team at Transitmix reached out to transit planners all over the county (including our firm), learning what did and didn't work about current practices and workflows. They created a beta version of a simple online tool that hinted at what might be possible. Finally, last week, Transitmix released a new video announcing the impending release of the professional version of the application, with critical features that offer the promise of a dramatically simpler, more open, and more easily understood transit planning tool.

Dynamic demographic and employment mapping and analysis, and side-by-side network and route comparisons are the main new features implemented here, to go along with the live updated costing, and deeply configurable frequency, span, and cost parameters the older version already includes. Transitmix continues to impress, creating a tool that simplifies and demystifies procedures that are too often known only to practitioners. We look forward to getting our hands on the full-featured product.

Basics: Controlling Altitude in Planning


One of the basic skills you should expect from a planning professional is the ability to control altitude.  Uncontrolled loss of altitude is a common cause of planning failure.

Altitude determines what you see.  If you are higher up from the surface of the earth, you can see a large area, but in less detail.  At lower altitude, you see a smaller area, but in greater detail.

In planning, there are high-altitude projects, which look at a large area (a city, a county, an urban region) and identify appropriate solutions to problems that exist at that scale.  There are also lower altitude projects, all the way down to parcel-level development approval, or, in my business, detailed designs of a transit station or a bus schedule.

Each project also moves through different altitudes.  As in a plane, you need to get up high to see the big picture.   If you don’t, if you just draw a box around a problem and try to solve the problem inside that box, you may do damage outside the box.  For example, if land use planning is nothing but development approval, then stuff will get built, project by project, without any attention to the aggregate consequences of that development — on traffic, on livability, on natural resources, etc.

On the other hand, plans that remain at high altitude — regional structure plans, vision plans, “strategic” plans, etc — don’t have any effect on reality unless they’re implemented by actions at lower altitudes.

So the airplane metaphor works like this:  To see clearly, we need to get our plane to a high altitude.  But to implement anything, we then need to land the plane.

The key is to lose altitude in a controlled and intentional way.  You look at the problem at high altitude and see the solutions that make sense at that level.  Maybe, for example, you identify a corridor that should have some kind of rapid transit but you don’t specify what the technology should be, or even an exact alignment.  Then, later, a study focuses just on that corridor and explores all the options for it.  All the remaining steps from there to implementation are part of a controlled loss of altitude until finally, on opening day, you’re on the ground:  The thing you planned is actually happening.

However, there is always the danger of uncontrolled loss of altitude, i.e. crashing the plane.  This happens when a conversation at a certain altitude is interrupted or shut down by a low-altitude issue.  For example, when we’re exploring the possible structure of a citywide network in a city, an operations manager may interject that a particular turn isn’t possible, or that this business would never let us put a bus stop there.  Those comments are plane-crashers.  If we succeed, at high altitude, in developing a network vision that excites people so that they want it to succeed, all those problems will be easy to solve.  But if we let those little concerns veto the high-level thinking, we’ll never be able to talk about the big picture.

This comes up often among people who have strong emotions about particular transit technologies.  They fervently support or oppose some technology option, so want to know the answer to the technology question before we have properly thought through higher altitude questions:  What are our goals for transit?  How do we balance predictably competing goals?  What kind of citywide network do we want?   What kind of mobility and access do we want to provide?

If those sound like hopelessly abstract questions, read the introduction to my book.  There, I explain how we can approach these questions so that citizens can answer them with an awareness of the consequences.  That, in turn, means that the decisions they make can be implemented.  The plane can descend, and finally land.  The key, as I explain there, is to listen to your plumber!

Photo:  Airplane Contrails- Creative Commons: Ian Renton, 2011




Luca Guala: driverless buses will be more transformative than driverless taxis

34Part 2 of my letter from Luca Guala, of the Italian consulting firm Mobility Thinklab.  (Part 1, on personal rapid transit, is here.)

Last summer, we tested driverless minibuses along a route of 1.3 km on a pedestrianized boulevard in Oristano, a small town in Italy. The idea was to test driverless vehicles mixed with traffic.

Why minibuses and not taxis? Firstly, because it is much simpler to teach a robot to follow a fixed route, rather than teach it to go anywhere the passengers want to go. Such a system is already operational in Rotterdam ( and it works well, but it has one drawback: the tracks are segregated and they represent an ugly severance in the urban tissue.

But if the vehicles are allowed to run with cars cyclists and pedestrians, a public transport route can be “adapted” with unobtrusive measures to accept driverless vehicles, and the people sharing the road will quickly learn to live with them. The main problem here was not technical, as legal.

Hence the idea of testing similar vehicles in an open field mixed with pedestrians. The first test we did had mixed results, the second test that will be done in La Rochelle, France this winter will take advantage of all that we learned in Oristano.

So what did I learn from all of this? That driverless cars very likely have a bright future, but cars they will always be. They may be able to go and park themselves out of harm’s way, they may be able to do more trips per day, but they will still need a 10 ft wide lane to move a flow of 3600 persons per hour. In fact, the advantage of robotic drivers in an extra-urban setting may be very interesting, but their advantages completely fade away in an urban street, where the frequent obstacles and interruptions will make robots provide a performance that will be equal, or worse than, that of a human driver, at least in terms of capacity and density.

True, they will be safer (especially because the liability for accidents will be borne upon the builder) and a robotic traffic will be less prone to congestion (I envision robotic cars marching orderly like robots, packed at 1.5 second intervals, while their occupants fume wishing they could take the wheel perfectly aware, but not at all convinced that their robocars are more efficient drivers than they are – or worse, they DO take the wheel overriding the … robots!), but I do not expect driverless cars to dramatically increase the capacity of a lane to transport persons. 

Driverless buses, on the other hand offer an interesting feature: the human driver is no longer needed, removing an important cost and several constraints.  This allows them to serve efficiently and economically low-demand routes and time bands, while allowing [agencies] to concentrate the number of manned buses on high demand routes at little added cost. 

I take all this automation talk with a grain of salt still, as I don't think we've begun to explore the human response to it.  But Luca is right about the key point:  driverless buses are a much easier problem than driverless cars, and their space-efficiency will continue to be crucial in busy corridors where even driverless cars will add up to gridlock.

Luca's last paragraph suggests that driverless buses will start with smaller vehicles in simpler situations, which is a possibility.  But of course, once the concept is proven, the economics of driverlessness will create pressure to bring the technology to big buses.  The same logic is also driving the movement to run fully-grade-separated without drivers, on the model of Vancouver, Dubai, and Paris.  The logic of driverless trains is easy: with automated train controls systems there is really not much for a driver to do in non-emergency situations, and these cities have found that those tasks are easily automated.  We are all used to small systems of this type, because we encounter them in large airports.  The driverless bus in traffic is a harder problem, but we will have solved all of those problems if we ever develop driverless cars.  In fact, the problem of the driverless bus, which never goes into alleys or minor streets, should be considerably easier, since navigation turns out to be one of the biggest challenges for the driverless car.  

Note also that the challenge of planning for driverless cars is not in envisioning a utopia where they have complete dominion over the street.  The future must be evolved, which means that we must plan for the interim state in which some cares are driverless and most aren't.  That is a situation where driverless buses could thrive, because they will be competing with something that — in terms of poor capacity utilization — resembles today's traffic on major streets, not a world optimized for the driverless car.

As Luca indicates, we know what the problem with driverless transit will be: long fights with labor unions who feel entitled to cradle-to-grave  security in a single job.  It will be one more kind of automation that requires people to retrain and to participate in a more complex and competitive economy.  In an ideal system, many drivers would be replaced by support jobs such as fare inspectors and roving problem-solvers; as on Vancouver's SkyTrain.  This seems to be what Luca is envisioning when he speaks of the continued need for "manned" services.  

But the real result of massively abundant transit — which is the real point of the large driverless bus  – will be massively more opportunity for all kinds of innovation and commerce to happen in a city,  unconstrained by the limits of car-based congestion.  That's a wrenching change, and I am as adamant as anyone about the need to protect workers from exploitation.  But in the long run, over a generation or two, the outcome will more interesting jobs for everyone.  Bus drivers shouldn't encourage their children to go into the same profession with the same expectations, but that's true of many jobs — perhaps even most jobs — in this rapidly changing world.