General

Blaise Pascal knew he was dying.  He was in his 30s and had been sick most of his life, but at least he didn’t have to worry about being forgotten.  He had already made transformative innovations in mathematics, physics, philosophy, and theology, and in his spare time he was assembling a collection of thoughts about God that would become the Pensées, which has been praised as some of the finest prose ever written in the French language.  He was fortunate to live at a time (the mid-1600s) when, if you were born to the right parents, nobody told you you needed to specialize.

So what did he do with the last lucid days of his life?  He invented fixed route public transport.

The vehicle used by Pascal’s service. Note that each had a fixed sign advertising the endpoints of the route. But who cares about the vehicle? What matters is the service.  Source: Taras Grescoe’s Substack.

Wikipedia currently says he invented the bus line, but that’s too narrow. Pascal’s network, which he called carrosses a cinq sols or “five penny carriages” used eight-passenger horse-drawn carriages, but they did what fixed route public transport does.  They operated predictable frequencies along multiple connecting routes, forming a network.  This is not just the ancestor of every city bus, but also of every train or tram.

Had this really not been done before?  Apparently not on land. Ferries are an ancient idea, both for crossing water bodies and for traveling along them.  They are fixed routes, of course, but that’s mostly because the shore is fixed.  Pascal’s idea was that even though carriages could go from anywhere to anywhere on Paris’s street network, a special kind of usefulness would arise if they didn’t do that, but instead followed paths that people could remember and plan around.

Here is the map of his complete network design:

Frequency ranged from 7.5 minutes to 15 minutes, so these came often enough that people could just go out and wait for them, not worrying about a schedule.  Their main failure was overcrowding and pass-ups, which of course is a kind of success.  Obviously, someone needed to invent a larger horse-drawn vehicle for this purpose, but that would wait a while still.  The first line began on March 18, 1662 and the whole network was operating by July, just before Pascal’s death, a pace of implementation that is hard to imagine today.  It’s likely that Pascal spent many of his final days thinking about this, when he wasn’t writing immortal prose about God.

If you want to trace the history of public transport from its roots in Pascal’s invention, please read this beautiful piece by the transit-obsessed travel and food writer Taras Grescoe.  Here, I want to go a little deeper into understanding what this service was.

Gazing at the map, I recognize many of the eternal principles of fixed route transit planning:  The lines try to remain far from each other, converging only on major destinations.  They are often perpendicular, which maximizes the odds that a connection between those routes will make lots of trips possible.  There are more or less straight lines running across the city — because where demand is spread uniformly, a straight line is more likely to match people’s desires than a winding one — and there’s an orbital line, yellow on the map that goes all the way around the edge in a two way loop.  Orbitals are a common shape because they make such effective connections with radial lines, and their length means they connect an unusual number of origins and destinations directly.

At age 11, Pascal had re-derived much of Euclid’s geometry from scratch because his father kept the books from him, thinking he was still too young.  So, dying at 38, Pascal probably could sense that these principles were mathematically right, even though they’d never been written down before.

But as a network designer I wanted to know more.  How did this map come about?  Did Pascal ever explain the design himself? What explains the biggest exceptions to the principles?  The routes aren’t as straight as they could be.  And why do so many of the lines converge at Luxembourg Palace in the southwest?  Much of the government was around there, but still, was that really such a hub of citywide demand?  I asked this question in English and French on both X and Bluesky, but I am not plugged into the French Enlightenment Transport History networks that must be out there, and most of Pascal’s biographers didn’t think this invention merited much discussion.  I did find this French article by Rémi Mathis[1] which shares some speculations.  (My loose translation.)

The first route [red on the map above] leads from Rue Saint-Antoine to Luxembourg, serving the Châtelet, the Île de la Cité and the Saint-Germain fair: it is clearly aimed at the bourgeoisie and la petite robe …and one will notice too that the routing links Pascal’s house with that of [his close friend and collaborator] Roannez while passing by that of the Arnauld family [close friends and the leaders of the abbey where Pascal’s sister lived].

A second and third route soon opened. They had to re-sequence their priorities when the king asked if there could be a route passing through the Louvre [presumably the orange line above].  The public mobbed the services to the point that often, several would pass by before there was room to board.  Attempts were then made to take advantage of this influx of customers: “The merchants of the rue Saint-Denis are asking for a road with such insistence that they even talk of submitting a request [presumably to the king] for one.”

Finally, in order to connect the routes together and allow connections with the whole city, the fourth route [yellow on map above], opened on June 24, 1662, was circular.

Now, this sounds very much like how you might think bus network planning is done, if you just follow journalism about it: It’s easy to assume that key leaders first look after themselves, connecting their own homes and destinations.[2]  Then, various powerful interest groups ask for a route, and the strong temptation is to draw a separate route for each of them.  Finally the local equivalent of royalty get involved, “asking” in ways that everyone understands to be a command. This story is sometimes partly true in my experience, but tends to be exaggerated.  Many journalists are rewarded for making people angry about the selfishness of the powerful, so they tend to emphasize that aspect of the process.  You might not even know that, if your community is lucky, some smart planners are actually thinking hard about how to serve the whole city well.

Pascal was one of those smart people.  His network design is much more logical than many of the networks I’ve seen that grew through the selfish demands of the few.  He’s running the fewest possible route miles to sustain the highest possible frequency, for example, rather than letting routes “fray” into infrequent variants in order to get closer to more important people.  On his map, the L-shaped red line, the first to be opened, looks rather political, but the rest all roughly fit the pattern of a network of radials and orbitals, designed to connect well with each other and thus maximize the number of origins and destinations connected in a reasonable travel time.

The fare, which was part of the service’s name, was intended to be affordable to a broad midsection of the Parisian social and economic scale.  Obviously, urban elites continued to hire carriages just for themselves, just as they grab an Uber for all their trips now.  But for the rest of the population, the only option had been to walk long distances across the city, often on muddy or icy streets whose poor maintenance and informal sanitation functions are barely imaginable to us today.

It worked.  It wasn’t just popular, but it achieved a degree of social mixing that characterizes all large-scale public transport.  One commentator notes that some relatively fortunate people still chose them:

Sauval, historian of Paris, states that “everyone after all, for two years, found these carriages so convenient that auditors and masters of accounts, advisers at the Châtelet and the court had no difficulty in using them to come to the Châtelet and the Palace”

Here is another distant echo of a pattern from today:  Government employees are more likely to use public transport than private sector employees. But more generally, a service designed to be efficient and thus affordable will attract a diversity of riders, including many who don’t really need the fare to be that cheap.  As a result, public transport, then as now, is a place where classes mix, and find no reason to be fearful of each other.

Again, read Taras Grescoe’s fine piece on the full legacy of Pascal’s invention.  Today, I just wanted to share my incomplete probings on the network design. I will update this post if I learn more.  Meanwhile, if you know anyone who is likely to know more about this, please share this with them.

[1] Hat tip to Emmanuel Marin, who writes the blog Sortir de Paris à velo (Getting out of Paris on a bicycle).

[2] For example, when Elon Musk was trying to promote his Boring Company car tunnels in Los Angeles, his first idea for a corridor extended from near his home in Bel Air to near his office in Inglewood.

Back in April, I recorded two hour-long courses for Planetizen’s library of courses on urban planning topics.  Planetizen has now polished these up with video effects and they’re ready for you to watch.

• Introduction to Transit Service Policy gives the tools you need to understand how public transit networks are designed and how this informs public policy.  I explain the geometric facts underlying how transit networks work and how these networks interact with the built environment to create ridership potential. This discussion includes a review of key principles and examples from various recent network designs.  You can watch this course for free until the end of January 2025.
• Planning Communities for Maximum Transit Access is geared more for people focused on city-building activities such as city planning, real estate and architecture, but advocates and elected officials will find it valuable as well.  In fact, it’s relevant for anyone making decisions about where to locate anything.  Here, I critique the assumption that rail service, but not bus service, is relevant to urban redevelopment.  Then, I offer an alternative approach to traditional transit-oriented land use planning, one where access to destinations via transit is the primary focus.  The key to this approach lies in locating and planning development to maximize access to opportunities using sustainable modes.  This course requires a regular Planetizen subscription, but I’m proud of it and I think you’ll find it worthwhile.

Both courses are relevant to audiences worldwide, although when dealing with the economic aspects of the topic I’m focused mostly on higher-wage countries (US, Canada, UK, EU, Japan, etc.)  The language is US English but any English speaker should have no trouble following it.

Here’s a clip to give you a sense of the feel of it.  The opening of the first course, and a unit on the geometric features of a city that make public transit efficient.

And here are some early reviews!

• “Mostly not new to me since I’ve followed Walker for a long time, but excellent and useful.”
• “I’m a big fan of JW. He understands and quickly cuts right to the heart of each issue. He offers better, shorter, clearer explanations of things I already understand but don’t explain to others as well. He explains clearly, logically, and dispassionately.”
• “A concisely detailed course about the Introduction to transit service policy. Well delivered by the Instructor.”
• “I am delighted with this course, It is short and effective in explaining about transit system and open my eyes and brain.”
• “The instructor Jarret Walker presented very well, and I was not bored during the full course, It improved my knowledge and thinking about transit.”
• “A great introductory to someone like myself who has little background in urban planning.”
• “He seemed very knowledgeable as well as personable and energetic. He was not boring to watch.”
• “Well thought out and presented
  Well balanced— detailed and informative but also excellent for an introduction”
• “I suggest he do more courses.”

I hope you enjoy these, and will share them with others who might be interested.

One of our firm’s biggest-ever transit planning projects, certainly in terms of land area, is unfolding at Pace, the agency that provides bus service for almost all of the suburbs of Chicago and a few corners of the city itself.  Pace is wrapped around all sides of the Chicago Transit Authority network, extending across an area roughly the size of Connecticut.   Here’s the current system map for a sense of scale:

The Pace network, with red denoting high frequency. (See legend.) Service is concentrated on the edges of Chicago and in the older satellite cities, leaving large developed areas, including much of DuPage County, unserved.

Right now, network alternatives are out for public review, so we need the input of people who live or work in the Pace service area.  If you know such a person, please share this with them, and point them to the project website here.

The Pace ReVision plan is happening in the context of a larger conversation about transit in the greater Chicago region, which I reviewed here.  All three of the region’s transit agencies are underfunded, especially as operating costs have risen post-Covid.  Pace, in particular, has never been funded to the degree needed to keep up with the vast growth of the Chicago suburbs over the last 70 years.  Even now, it’s service is heavily concentrated in the older areas that were built out over 70 years ago, both on the edges of Chicago and in the older satellite cities such as Elgin, Waukegan, Joliet and Aurora.  So any meaningful improvement in service needs to presume new resources, and make the case for them.

For that reason, the Pace ReVision project has put three alternatives before the public:

• Plus 10 – Limited Investment.  This shows what we could achieve with a return to 2019 service levels, which may be possible within existing funding.
• Plus 50 – Ridership Focus.  This shows what the network would look like if we could expand service 50%, to roughly per-capita service level of Connecticut Transit, and if the overriding goal were ridership.
• Plus 50 – Coverage Focus.  This shows the same 50% growth but with emphasis on the goal of coverage.

All this is explained in this graphically rich Executive Summary, which I hope you’ll peruse.  If you want to go into even more detail, there’s a full report explaining even more of the thinking.

Above all, we need people to engage!  This is the moment for people in the Chicago suburbs to think about what they want transit to be.  Tell us now for maximum impact!

Tomorrow’s US general election is a massive turning point in history, but on the same day, many cities are also making big decisions around transit and urbanism.  Here’s a rundown of all the main measures on the ballot across the country.  Meanwhile, I’d like to highlight one that I find especially interesting: the “Choose How You Move” proposal in Nashville.  It’s a smart combination of measures, including bus infrastructure, bus service, pedestrian infrastructure, and traffic signals, while the key word “choose” emphasizes that the point is to expand the freedom of people in the Nashville region.

In September I had the chance to spend a few days in Nashville, at the invitation of a group of civic leaders called Cumberland Region Tomorrow.  I did a keynote at their event and also had a chance to meet with staff at the transit agency, WeGo.

Like many sunbelt cities, Nashville has been growing in a car-dependent way for decades, but meanwhile, it has evolved a dense core that is just too dense for everyone to drive.  The city has three main functions concentrated downtown: State government, the usual mix of business office towers, and the country music industry’s main tourist attractions.

Just outside of downtown is Music Row, where the country music record labels have their offices, and Vanderbilt University with its large medical center.  This density is typical:

This is enough dense development to generate a lot of need for alternatives to private car travel, but the street network lags behind that demand.  Many main streets are state highways, managed for vehicle flow at the expense of nonmotorized human flourishing.  Many lower-income people live on or near these highways, which are often unsafe for pedestrians, lacking both adequate sidewalks and a reasonable spacing of safe places to cross.  Prevailing driving styles are aggressive even by US standards.

The transit network is far better than I’d been led to expect.  The buses are modern, and there is a downtown transit center that should be the envy of many nearby cities.

But its main issue is quantity — there just isn’t much service — and the tendency of buses to get stuck in traffic.

Nashville’s last transit adventure at the ballot box was in 2018, where a proposed ballot measure failed with 64% voting no.  TransitCenter reviewed the advocacy lessons here, but fundamentally, this was a plan for major light rail investment, including a tunnel under downtown, as well as a few Bus Rapid Transit lines.  That made it very expensive and at the same time very specialized.  The concentrated investment in a few corridors would leave much of the city feeling left out — a routine problem with infrastructure-heavy transit plans.  The plan was also all about transit, and didn’t connect the dots to how many Nashvilleans experienced their transportation problems, for example as traffic congestion or the danger to pedestrians.

The new measure is much more balanced.  It includes operating funds for expanded transit, infrastructure for bus priority, but it also includes sidewalks and traffic signals.  That means more money will go to making high-speed streets safer.  That’s all good for transit — in fact, it’s essential for a great transit experience — but it also has a large constituency of people who don’t necessarily care about transit all that much.  While I wish the website provided more technical detail to those who are interested, it does a good job of connecting the plan to issues that matter to people, including housing and even loneliness.

I’ll be rooting for transit measures all over the US tomorrow, but this one will be especially instructive, because if it succeeds, it could be a good model for the next generation of measures in car-oriented cities.

Update: It passed by a big margin!

Following up on this post about the Northern Ireland public transport situation, I was interviewed recently by John Campbell as part of a BBC program on the topic.  I’m right at the beginning, and my part runs for about 10 minutes.  Hope you enjoy.  It’s here.

I have mixed feelings about the whole system of awards that runs through the public transit industry in the US, but it’s still nice to see real excellence rewarded.  My colleague Ricky Angueira showed up on Mass Transit Magazine’s list of leading young professionals, their “Top 40 Under 40.”  This award begins with a nomination from one of our clients, not from us.

Since joining our Arlington, Virginia office in 2019, Ricky has become a valued project manager and service planner.  He managed our recent network plans in Williamsburg, Virginia and Knoxville, Tennessee, and also led the analysis team for our complex work on service restoration priorities for San Francisco MTA in 2021.  He’s become adept at all the aspects of a network plan, including navigating the local politics of each community.

Ricky also leads public-facing network maps for our clients.  He managed the design and creation of maps in Miami, Boise, San Juan (Puerto Rico) and now San Antonio, and is now starting a similar project in Cambridge, UK.

Finally, as Scudder Wagg takes over as President of our firm, Ricky will be the new manager of our Arlington office.  It’s great to see this recognition of one of our leading talents.