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.

 
 
 
 

Why exactly do Britain’s rail services to the cities of the South West keep getting cut off?

You see the problem? The line through Dawlish. Image: Geof Sheppard/Wikimedia Commons.

If you’ve ever looked at some picturesque photos of British railways, perhaps in a specialist railway magazine – we’re not judging – then you’ve probably seen images of the South West Railway sea wall, with trains running tantalisingly close to the sea, either framed by blue skies and blue water or being battered by dramatic waves, depending on the region’s notoriously changeable weather.

Designed by Isambard Kingdom Brunel and open since the 1840s, the line was placed so close to the water to avoid the ruinous cost of tunnelling through the South Devon hills. From Dawlish Warren to Teignmouth the line is, with the odd interruption, exposed to the sea, affording the striking images so beloved of rail photographers. Its exposed placement also inevitably leads to speed limitations, closure and damage to the infrastructure. This would be a matter of purely local interest were it not for the fact that the sea wall is an unavoidable link in rail routes to the South West.

Main line trains run from London Waterloo and Paddington down to the Devon hub of Exeter St Davids, before continuing on to Plymouth, Truro and other destinations on the peninsula. Trains leaving St Davids reach the bottleneck very quickly, following the river Exe and its estuary, before dipping behind the sand dunes and emerging on to the sea wall.

What happens to the track at the small seaside towns of Dawlish Warren and Dawlish therefore has an impact on the whole region. South Devon and Cornwall are inaccessible by rail when the sea wall is temporarily closed or, as happened in January 2014, when storms breached the sea wall altogether, damaging it so severely it took weeks to repair.

While it’s easy to understand the economic logic of building the sea wall in the first place, unsurprisingly the economics of maintaining the damn thing have proven less compelling. The sea wall is considered to be, per mile, the most expensive stretch of Network Rail’s network to maintain. It’s also baffling to modern eyes why the main line rail services for a whole region would flow through such a vulnerable bottle neck.

The Devon rail network. Image: Travel Devon.

As with so many oddities of the British rail system, these perversities emerged from the rapid change that came in the mid 20th century through war, nationalisation and Dr Beeching.

The need for a Dawlish Avoiding Line was identified as early the 1930s. This would have diverted from the existing route at Exminster, and rejoined the line between Teignmouth and Newton Abbot, passing through Dawlish inland. Tweaks to the plan were made, but by 1939 construction was under way, only to be suspended when war broke out. Work on the project did not resume after the war, and when the Great Western Railway became part of the nationalised British Railways it was not a priority. The land for the Dawlish Avoiding Line was later sold by British Rail and has subsequently been built on, so that was that.

In the 1960s, Dr Beeching’s axe fell on rail routes across Devon, including the lines through North Devon that had provided an alternative rail route through the county. Those closed lines have also been extensively built on or converted to other uses, leaving a single main line through Devon, and rendering the sea wall unavoidable.

In recent years the condition of the sea wall has become increasingly precari


ous. That’s not only due to storm damage to the wall itself, but also due to the potential for erosion of cliffs overlooking the rail line, resulting in falling rocks. While this has been an ongoing issue since... well, since the sea wall was opened over 150 years ago, the storm of 4 February 2014 brought the matter to national attention. The visual of twisted rails hanging out into empty space illustrated the problem in a way pages of reports on the precarious nature of the line never could.

An army of Network Rail workers descended on Dawlish to get the line re-opened within two months. But repairing the damage hasn’t resolved the base problem, and climate change increases the likelihood of further major storm damage. In October 2018 the line was hastily closed for weekend repairs when storms resulted in a six foot hole appearing under the tracks near Teignmouth.

Supportive noises of varying intensity and occasional oblique funding commitments have come from government in the last five years, and investigations and consultations have been conducted by both Network Rail and the Peninsula Rail Task Force, a group set up by local councils in the wake of February 2014. Proposals currently on the table include Network Rail’s plan to extend a section of the sea wall further out to sea, away from the crumbling cliffs, and reopening the Okehampton line across Dartmoor to provide an alternative rail route between Exeter and Plymouth. 

But in spite of talk about investment and grand plans, no major work is underway or funded, with Network Rail continuing their work maintaining and repairing the existing line, and the situation seems unlikely to change soon.

Massive spending on rail infrastructure in the South West is a hard Westminster sell, especially in the Brexit-addled political climate of the last few years. And with the parliamentary map of the region dominated by blue there’s been little political will to challenge the vague commitments of government. One of the South West’s few Labour MPs, Exeter’s Ben Bradshaw, is particularly damning of the failure of Tory MPs to put pressure on the government, using a recent column for Devon Live to describe them as “feeble”.

But regardless of the political will to solve the problems of rail in the South West, barring a string of unusually gentle winters, the issue isn’t going away soon. If the South West is to be an accessible and successful part of the UK, then it needs stable rail infrastructure that can survive whatever the weather throws at it.