The problem of space: why Elon Musk doesn't understand urban geometry

Elon Musk unveils the new Tesla Model X Crossover SUV in Fremont, California, last September. Image: Getty.

He may be a brilliant visionary in all kinds of ways, but Elon Musk’s “Master Plan, Part Deux” makes grand plans for the abolition of fixed route public transport without thinking clearly about urban space:

“With the advent of autonomy, it will probably make sense to shrink the size of buses and transition the role of bus driver to that of fleet manager. Traffic congestion would improve due to increased passenger areal density by eliminating the center aisle and putting seats where there are currently entryways, and matching acceleration and braking to other vehicles, thus avoiding the inertial impedance to smooth traffic flow of traditional heavy buses.

“It would also take people all the way to their destination. Fixed summon buttons at existing bus stops would serve those who don’t have a phone. Design accommodates wheelchairs, strollers and bikes.”

Musk assumes that public transit is an engineering problem, about vehicle design and technology.  In fact, providing cost-effective and liberating transportation in cities requires solving a geometry problem, and he’s not even seeing it.  What’s more, he’s repeating a very common delusion, one I hear all the time in urbanist and technology circles.

Musk’s vision is fine for low-density outer suburbia and rural areas.  But when we get to dense cities, where big transit vehicles are carrying huge ridership, Musk’s vision is a disaster.  That’s because it takes lots of people out of big transit vehicles and puts them into small ones, which increases the total number of vehicles on the road at any time.  The technical measure of this is Vehicle Miles (or KM) Travelled (VMT).

Today, increasing VMT would mean increased emissions and increased road carnage. But let’s say technology has solved those problems, with electric vehicles and automation.  Those are engineering problems.  Inventors can work on those.

There is still, and will always be, the problem of space. Increasing VMT means that you are taking more space to move the same number of people. This may be fine in low-density and rural areas, where there’s lots of space per person.  But a city, by definition, has little space per person, so the efficient use of space is the core problem of urban transportation.

The tyranny of maths

When we are talking about space, we are talking about geometry, not engineering, and technology never changes geometry.  You must solve a problem spatially before you have really solved it.

The reigning fantasy of Musk’s argument is that we must always “take people all the way to their destination”. But to do this we must abolish the need to ever change vehicles – from a train to a bus, from a car to a train, from a bus to a bike – and of course we also abolish walking.  This implies a vision in which buses are shrunk into something like taxis, because a vehicle going directly from your exact origin to your exact destination at your chosen time won’t be useful to many people other than you.

So a bus with 60 people on it today is blown apart into, what, little driverless vans with an average of three each, a 20-fold increase in the number of vehicles?  It doesn’t matter if they’re electric or driverless.  Where will they all fit in the urban street?  And when they take over, what room will be left for wider sidewalks, bike lanes, pocket parks, or indeed anything but a vast river of vehicles?

There are audiences for which Musk’s vision makes mathematical sense sense: people for whom useful high-ridership transit isn’t an option anyway.  There are two big categories of these people:

  • People who live in outer-suburban and rural areas, where space is abundant and high-ridership transit isn’t viable;
  • The top 20 per cent or so of urban residents, who can afford to use relatively expensive servies that would never scale to the entire population of the city.

If you are in one of these categories, your most urgent task is to remember that most people aren’t like you, and that cities are impossible if everyone lives according to your personal tastes.  As Edward Glaser said, “one’s own tastes are rarely a sound basis for public policy”.

That issue, right there, is the great disconnect between tech marketing and genuine urban problem-solving.


Tech marketing is all about appealing to elite personal tastes.  It runs on the assumption that whatever we sell to the wealthy today we can sell to the masses tomorrow.  

But some things stop working when everybody buys them. Cars in dense cities, for example, are not a problem when only the top 20 per cent are using them; it’s mass adoption of cars that makes them ruinous to a dense city and to the liberty of its citizens. Ask anyone in a fast-growing developing world city about that.

Here is the harm that this all this elite chatter about abolishing the bus is doing: it’s introducing fatal confusion into the discussion of urban development.

The density solution

Dense cities that want to live in the real world of space and time, and that do not want to become dystopias that are functional only for the rich, need to use urban space efficiently. There is some simple and well-proven maths about how to do this, which is also the maths of how transit systems achieve high ridership.

These cities need to organize themselves around frequent transit corridors, where big-vehicle frequent transit, bus or rail, can prosper, allowing the city to grow dense without growing vehicle trips.

Someday some of these corridors will be rail or Bus Rapid Transit. But the only way to grow enough corridors quickly, so that you cover much of the city with frequent service that can succeed in ridership terms, is to take frequent fixed-route bus service seriously. If you don’t do that in your land use planning, you’re going to end up building a city where fixed transit is geometrically impossible, and then you’ll have to settle for Musk’s vision. Geometrically, that vision can only mean liberating transportation just for the top 20 per cent – or electrified, automated gridlock for everyone.

Smart cities aren’t just the ones that chase the latest technology fads. They’re the ones that think carefully about the spatial, geometric problem that a dense city is. Because if it doesn’t work geometrically, it doesn’t work.

Jarrett Walker is an international consultant in public transit network design and policy, based in Portland, Oregon. He is also the author of “Human Transit: How clearer thinking about public transit can enrich our communities and our lives".

This article was originally written for his blog, and is reposted here with permission.

 
 
 
 

Vanilla Skybus: George Romero and Pittsburgh’s metro to nowhere

A prototype Skybus on display near Pittsburgh. Image: BongWarrior/Wikimedia Commons.

The late director George A Romero’s films are mainly known for their zombies, an association stretching from his first film, 1968’s Night of the Living Dead, to his last as director, 2009’s Survival of the Dead.

But many of them are also a record of Pittsburgh, the city he lived and worked in, and other locations in the state of Pennsylvania in the late 20th century. Martin (1978), for example, isn’t just a movie about a kid who thinks he’s a vampire: it’s a moving portrayal of the post-industrial decay of the Pittsburgh borough of Braddock.

Though born in New York, Romero studied in Pittsburgh and stayed in the city after graduation, shooting commercials as part of the successful Latent Image agency. It was in collaboration with advertising colleagues that he shot his debut Night of the Living Dead. On both that movie and subsequent films, Romero and his colleagues used their experience and connections from the agency to secure cheap and striking locations around the city and state. 

It’s in Romero’s little-seen second film, 1971’s romantic drama There’s Always Vanilla, that a crucial scene touches on a dead end in the history of urban transport in Steel City.

In the scene Vietnam vet Chris, only recently returned to town after a failed music career, sees his father off on a train platform, after an evening where Chris got his dad stoned and set him up with a stripper. (It was the early 1970s, remember.) An odd little two-carriage metro train pulls up on an elevated concrete platform, Chris’ father rides away on it, and then Chris literally bumps into Lynn, whom he then both gaslights and negs. (It was the ‘70s.) You can see the scene here.

A screenshot from There's Always Vanilla, showing the Skybus through a chain link fence.

If you don’t live in Pittsburgh, you might assume that funny little train, still futuristic forty years on, is just an everyday way of getting around in the exciting New World. Who knows what amazing technology they have over there, right?

In fact, the Transit Expressway Revenue Line, more snappily referred to as the Skybus, not only doesn’t exist today: it hardly existed at all, beyond what we see in that short scene. In the 1960s there were plans to replace Pittsburgh’s street car system with a more up to date urban transit system. The Skybus – driverless, running on rubber tires on an elevated concrete track with power provided with an under rail system – drew enough support from the Port Authority and Federal Government for them to fund a short demonstration track at the Allegheny County Fair, at that point a local institution.

It’s this demonstration track and train that appears in There’s Always Vanilla. Film makers love isolated systems like this, or the UK’s many heritage railways, because they allow for multiple takes and a controlled environment. So it made sense for Romero to use this local curio rather than seek access to an in-use station.


The sequence in Vanilla shows that the Skybus system worked, and as a potential metro system it looks quite striking to this day with its curved windows and distinctive logo. But the proposed system wasn’t popular with everyone, and cost concerns and political wrangling stalled the project – until it was finally rejected in favour of a more conventional steel wheel on steel rail transit system.

The demonstration track was pulled up in 1980, although the small station and platform seen in the movie remains: Romero expert Lawrence Devincentz narrates a photo tour of the building on the blu ray of There’s Always Vanilla.

Vanilla was renamed and barely seen on release, but is now available as part of a boxset of Romero’s early works from Arrow Video, in ridiculously pristine 2K digital transfer. The Skybus is there too, a curio of Pittsburgh history caught on a few short minutes of film. Neglected back then, both seem considerably more interesting now.

‘There’s Always Vanilla’ is available on blu ray as part of Arrow’s ‘George A. Romero: Between Night and Dawn’ box set, and will receive a standalone release later this year.

Mark Clapham used to work in rail regulation, but now writes things like this. He tweets as @markclapham.