Sunday, January 28, 2018

"A conversation about how public transport really works"

My interest in transport planning is usually the financial angle,* maybe quasi-esoteric complexity stuff e.g. "Study on Fractal Features of Transportation Network in Xuzhou City". Or, transport planning as part of the wider discipline of urban planning (and anti-planning).

Contra that dilettante approach, in this piece the FT's Izabella Kaminska interviews an actual professional.

From FT Alphaville:
Jarrett Walker is a public transportation expert and author of the 2011 book Human Transit, which seeks to dispel many of the myths and fallacies misleading debate and investment in public transport across the world. 

Written before ride-sharing apps became the thing they are today, Walker’s core thesis — that urban geometry must be respected at all stages of public transportation development — still holds true. Worryingly, it’s also the key reality still ignored by those seeking to disrupt the world’s transport systems (supposedly for the better) today.

Walker blogs at, where he continues the campaign to inform the world about the physical constraints of urban geometry that must be respected if we are to build better systems that don’t just service the urban elite. He also tweets at @humantransit, where he sometimes gets called an idiot by Elon Musk.

Earlier this month FT Alphaville spoke with Walker about what people misunderstand about how public transport works. A technology failure prevented it being a podcast, so here is a (slightly) truncated transcript of that long conversation:
FTAV: Tell us a bit about your public transportation credentials?

WALKER: I did not ever formally study transportation planning; I learned it by doing it. So, I had a geeky interest in public transport as a teenager and in every public transport authority, you will find some of these teenagers hanging around and when I decided not to go forward in academia, I went back to this interest and got into a consulting firm and went from there.

So, I am a PhD, who has learnt everything he knows on the street, pretty much, as far as transport planning is concerned but I do believe that my humanities education is an important perspective on public transport; I’m starting to use it more and more now as I find it necessary to comment on the narratives going on inside of and behind the scenes in what appear to be technical arguments. So that’s pretty much my story. I got started in a consulting firm in San Francisco. I was there for about 12 years, moved to Australia for five years and I worked in Australia and New Zealand for five years and then came back to Portland, Oregon and set up my current firm, Jarrett Walker and Associates, which has been going for about seven years and is about ten people now.

I started the blog, I think, in 2009 and the blog, of course, was a way of gradually writing a book and the book, Human Transit, came out at the end of 2011 and so a lot of the material from the first couple of years of the blog got organised and presented more clearly, I think, in that book.

FTAV: What’s the core thesis of book?

WALKER: Well, there are always new fads coming along. So, and once you’ve been in this field for 25 years, you’ve seen a lot of these come and go. What I was trying to do in the book was give people a grounding in the geometric facts of the matter, which are not going to change, no matter what new idea has come along and so that’s part of, I think, why the book is not in any sense out of date, even though it doesn’t talk about the current fads [like Uber].

FTAV: Your point, if I understand it correctly, is that fancy apps are not going to change the reality of the urban geometry that surrounds us. So, for example, we can unleash all the algorithmically controlled self-driving cars we want into the system, but if more people want to cross a bridge at a specific time than there is bridge capacity available to handle the flow, we will be sitting in traffic jams regardless?

WALKER: That’s a very fair assessment. I think, it takes me back about five/seven years ago; the line everyone was repeating was that the most important innovation in transportation is the smartphone and the assumption there, what continues to be the assumption in the tech industry is that transport is primarily a communications problem. And as we’ve seen, there certainly were communications problems in transport and the smartphone and the technologies we have on the smartphone have certainly done a great deal to take a certain amount of friction out of the system and by making it much easier to summon transport services spontaneously. But we now have enough experience to know what we should have known all along, which is that transport, nevertheless, takes place in physical space and physical space obeys laws of geometry and physics and no technology is ever going to change geometry—never has, never will.

So, I think, we’ve seen, as with this attempt to somehow harness physical space through the power of apps, that there’s just a basic philosophical problem there, which is that transport is fundamentally a physical, spatial problem. It is not fundamentally a communications problem or to the extent that it was a communications problem, we’ve gone most of the way, I think, in taking that friction out of the system. And what Uber is discovering, I think, what a lot of these tech firms are discovering is that taking that friction out of the system did not transform the fundamental reality of space and the math of labour and so on, which have really been the facts that have determined what’s possible in passenger transport and will continue to determine those things.

No, of course, the driverless car people will say, no, cars will fit closer together and they’ll be smaller and so we’ll fit more of them over the bridge but that’s a linear solution to an exponential problem. The other dimension of this problem that you must keep in mind is the problem of what we, in the business, call induced demand. And induced demand is the very simply idea that when you make something easier, people are more likely to do it and this is why, for example, when you widen a motorway, the traffic gets worse or it fills up to the same level of congestion that you had before. It’s because when you actually create new capacity, people use the capacity and you end up back in the same point.
FTAV: That sounds a lot like Jevon’s Paradox in economics.

WALKER: If there’s a single concept that transport professionals almost all understand and almost nobody else understands, it’s this notion that the relationship between demand and usage is actually circular, the relationship between demand and capacity is circular. That is to say if/when we create more capacity, we trigger more demand. There’s a huge issue then because one of the things that Uber has done is very effectively induce demand for a whole bunch of new car trips in the city that weren’t happening before and this has had the effect, of course, of increasing congestion. The other thing they’re done, of course, is draw people off of public transport, which is a great way to increase congestion. And so this is why it’s tricky and this is why in your example of a bridge, if you widened the bridge but lots of people want to cross it, you’ll end up with a wider bridge that’s exactly as congested as it is now....

*"Switzerland Begins Two-Year Trial of Driverless Buses" (plus money, art, glory and sex)