What is a Spine?

A spine is a really powerful network design idea that takes a moment to explain.  This is how a spine works, in an example from the Dublin bus network redesign proposal.

[That diagram is by Dublin-based graphic designer Kevin Carter, and uses a style common in the UK.  The National Transport Authority has hired Kevin to complete these diagrams for the other six spines.   If you’re on Twitter, follow him at @yascaoimhin.]

A spine is several bus lines designed to share a common segment, with the buses evenly spaced on that segment to deliver a very high frequency.  In this case, each spine branch runs every 15 minutes all day, so the common segment is every 3.75 minutes on average.

If you are in the inner city, where all the spines are running on their common segment, you just say “take any bus whose number starts with A”.  The result is a high-frequency network map that’s easy to draw a map of, and to learn, remember, and explain.

(That image is ours, from the summary report.)

In the case of the A spine, all four branches are every 15 minutes all day so the common segment is a little better than every 4 minutes all day.

The National Transport Authority also did an animation, here.

Many, many cities have a geography where this structure makes sense.  As you move out from the centre, the area to be covered gets wider but the frequency need gets lower, so you branch.  But you make it legible.   The inner city needs an extremely frequent line that’s easy to learn and remember, so we just explain that the A-spine is made of all the buses whose numbers start with A.  Presto.  You have a simple network of inner-city lines where the bus is always coming soon, exactly what people moving around in the core need.

Once you understand it, it’s simple.  But it takes a moment to learn, and different people learn it differently.

Dublin: Call Copenhagen

A few silly things (and many smart ones) have been said our proposed bus network redesign for Dublin, but the silliest is that it’s “North American.”

Actually, it’s European:

Copenhagen has much in common with Dublin. A maritime city and national capital about the same size and not that different in shape. It has a frequent heavy rail system like DART (marked S), and one metro line (marked M) but no trams.

Look at the bus routes.  The route numbers ending in A are high-frequency services all coming every few minutes and they form a spiderweb-shaped grid.  Look at 3A and 4A on the left.  They run north south on the west side and then curve to the right in the north.  We call those orbitals, because they orbit the city centre instead of going into it.  Intersecting them are a bunch of radial lines that go into the centre.  Wherever these lines cross (or where they cross rail lines) you can change easily.  That’s what makes it easy to go anywhere, not just into the centre.

Several areas, you’ll notice, are on only an orbital.  If you are on an orbital-only stop, you may have to change buses (or take a bus to a train) to reach the city.  The ticketing system, however, gives you unlimited use of the system for a fixed time.  NTA is proposing a similar 90-minute ticket, so that your fare never depends on how many times you change vehicles.

And if you don’t think people will use this kind of network if it requires them to change buses in bad weather:

DublinCopenhagen
Average daily low (January)3.9 C0.8 C
Annual precipitation758523
Days with rain or snow per year129157
Days with snow per year1621

We practice what we preach. My home town, Portland, Oregon, has almost exactly the same climate.  I change buses in the rain all the time.  In fact, sometimes I ignore my infrequent direct bus to the office and instead take two frequent buses, because with so much less waiting, I get there sooner.

Many European bus networks show the same principle in their design.  I chose Copenhagen because it’s especially comparable, and they draw an especially clear map.

Again, I don’t want to pretend this is easy.  But it’s certainly European (and Asian, and North American, and South American, and Australian) if you care about that.

Do We Need a New Theory and Name for “Bike Lanes”?

Important: I’m thinking out loud here!  The title is a question because I don’t have answers and am not proposing anything.

Now that we have scooters sharing bike lanes, I wonder if we’ll need to think more clearly about the different kinds of lane on a street and what their real defining features are.  This could lead to different words.

We separate traffic types for two reasons:

  • Speed, so that faster vehicles aren’t often stuck behind slower ones,
  • Width, so that we use less space to serve the needs of narrower vehicles, thus using scarce space more efficiently overall.

Sarah Iannarone and I were chatting about this on the bus this morning, and after that she went straight to the whiteboard and drew this:

The idea here is that a street with a speed limit over 30 km/hr will need to separate these three kinds of traffic, because they differ in both speed and width.  At lower speeds you can mix them more.

Where speed and width come apart, however, speed has to be the defining feature.  You can’t ride a motorbike at 30 km/hr down a “bike” lane, even though it may be narrow enough.  You have to ride it in the traffic lane, even though that’s a waste of space.

All this came up because I was trying to think of the correct new term for “bike lane” as we proliferate more vehicle types that run more or less at the speed and width of bicycles but are clearly not bicycles, such as electric scooters.  The two logical terms seem to be narrow lane or midspeed lane.  One way or another the two concepts will need to track with each other.

I wonder if this kind of language can make our sense of the role of these lanes more flexible, and thus less divisive.

There is a lot of room for individual choice here about which lane to use.  Cyclists, for example, already choose between midspeed “bike” lanes and full-speed traffic lanes, depending on their preferred balance of speed and safety.  Meanwhile, an 8-year-old learning to ride a bike should probably be on the sidewalk.  Another reason that “cycle lane” may be a misnomer.

This isn’t easy.  The things that might go in a midspeed lane have very different acceleration and stopping characteristics, all of which will cause friction.  When I raised this thought on Twitter, I got lots of responses expressing concern about different kinds of vehicles sharing a lane.  But even with just the few lane types that we already have, it’s hard to make them all fit.   We’ll never have a separate lane for every type of vehicle that needs a slightly different speed, acceleration, or stopping distance.  So again, I’m asking a question, not answering it.

Finally, Sarah assigns transit to the full-speed, widest lanes, but of course that leaves open the question of transit priority within that territory.  Where there’s demand and room for a bus lane, it should be automatic in my view.  It doesn’t even need to be “constructed” necessarily.  Just paint the lane red.

 

Why We’re Used to Some Outrage at Network Redesigns

Here are some things that happen whenever a big bus network redesign is first proposed to the public. They are happening in the Dublin network redesign process right now, but to some degree they’ve happened on every project I’ve done over my 25-year career.

  • People assume that the plan is more final than it is, so they feel they need to gather forces in angry meetings and attack us, when in fact we want their detailed comments so we can address them.
  • We consult the public about the plan and they tell us, as we’re consulting them, that we’re not consulting them. (This is an understandable consequence of the previous point; people assume they’re being told when in fact they’re being asked.)
  • People say that while we’ve consulted some people, we haven’t consulted everyone in the right way.  (This is an understandable complaint, and often a valid one, but we will always get it no matter how much consultation is done. People rely on so many different information sources, and need things explained in so many different ways, that reaching everyone the right way is a potentially infinite task.)
  • Some people hear only that “there won’t be a Route 54” and begin holding rallies to “Save the 54,” without knowing or caring what service is proposed to replace the 54.  (Sometimes we’re just changing the number!)
  • Media headlines often inflame this confusion, with headlines about bus lines being “scrapped”.
  • People attack the whole plan because one local detail isn’t right.  (Many of the details that people are outraged about in Dublin are fixable, now that we have heard about them.  That’s why we’re consulting you about it now, to help us get the details right!)
  • Unions representing bus drivers, understandably seen as experts in some circles, will often put out their own messages tied to their own interests.
  • People attack the consultant.  (It’s not the first time my tiny 10-person firm has been called “corporate.”)
  • Some sympathetic person explains to me that people in their city or country are just crazy in some way, and I assure them that no, this is what happens everywhere, from Russia to the US to New Zealand, when a proposed network redesign comes out.  Because what everyone is doing is completely understandable in their situation.

Here, for example, is a deep dive into a current network redesign in Canberra, Australia (which I helped lay the groundwork for years ago).  You will see all of the themes I’ve listed.

What’s happened next, in all my projects, is that we collected the comments and fixed what was fixable, which turned out to include most of the details that had most inflamed people.  In most cases that addressed enough concerns that the plan moved forward and was a success.  It solved the problems it was meant to solve, and once people got used to it many of them discovered that it wasn’t as bad as they thought.

That doesn’t always happen, though. Sometimes elected leaders panic at this point and stop the plan, leaving all of the existing problems in place.

For me, there’s a reason to be happy about all the controversy:  It means people care.  The least controversial projects I’ve done were in very car-oriented places where few people (and no powerful people) cared what the buses did.  I would much rather be dealing with controversy.

The key thing is not to panic when we hear outrage at this stage of the process.  While was it was especially inflamed by misinformation in Dublin’s case, it’s a normal phase in the conversation.

And again, that doesn’t mean we’re not listening. The whole point is that we are listening, so we can make the plan better.

[Note: I will be mostly away from the internet, until the 20th August.]

Dublin: We Need Your Comments!

 

The proposed Dublin bus network redesign has been out for public comment for about a month. It’s very important that Dubliners learn about the plan (there are many ways to do this) and then to comment on it before the end of September.

Sadly, a great deal of false or misleading information is out there.  Falsehoods appeared on social media within minutes after the report was posted, long before anyone could have read it.  Then, a major bus drivers’ union distributed a table that claims to describe the plan, but whose real effect is to cause needless confusion and panic.  For example, it describes existing route 140 as “gone” even though every segment of that route continues to be served, mostly at higher frequencies, in the new plan.

We’ve put out more accurate information, including a detailed route-by-route table and interactive maps that help you see how an existing route would be replaced, and how the network expands where you could go on public transport.

But of all the falsehoods being spread, the biggest is that NTA has “decided” to implement the plan.  Many people are outraged because NTA “decided on” the plan without consulting them.

The answer is:  NTA is consulting you now.  That is what the draft plan is for, to put ideas out there for people to respond to.  Nothing has been decided.  What you tell us now will guide what happens next.

So again:

  1. Read my overview of the plan here.
  2. Explore the plan here (busconnects.ie), or at one of the meetings (check back for more to come).
  3. If you have a specific objection to the plan, use the survey to explain that objection.
  4. There’s no need to attack the whole plan unless you hate the whole plan.  We may have gotten something wrong in your neighborhood, but that doesn’t mean the whole plan is a bad idea.

Again big ideas of the whole plan are:

  • a much simpler, more frequent network on which more people can get to more places sooner …
  • which requires a few people to interchange where they now have a direct bus …
  • and which sometimes requires a little more walking, though almost never over 400m.

If you hate these ideas, you should definitely oppose the whole plan.   (Look at Chapter 5 of our report if you want to understand why these things are connected. )

But meanwhile, we need everyone’s detailed feedback and comments, so that we can make the plan better.  Start here.

Dublin: New Map of Where You Can Go, and How

As the public consultation on the Dublin bus network redesign ramps up, we’ve been working hard to get information out in as many ways as possible.

Today, at busconnects.ie, you’ll find an interactive map that shows you two things:

  1. Where Can I Go?  Click a location, and the tool shows you how the plan changes were you can get to, in 30, 45, or 60 minutes midday, including the average waiting time at the start of your trip.  It also shows you the change in the number of jobs or school enrolments that you can get to in that time.
  2. Show Routes.  This gives you an interactive layer showing all the proposed new routes, with the most frequent routes shown most prominently.  This is a good tool for exploring the new network, and seeing how you could make various trips within it.

Let’s look closer:

Where Could I Go?

Click “Get Started” and then click any point on the map.  Let’s select Priorswood in Dublin’s north east.  Then, in the upper left, you can choose whether you want to see what’s reachable in 30 minutes, 45 minutes, or 60 minutes.  Let’s choose 60 min.

See the legend at left.

  • Dark blue is the area that you can still reach in that time.  (You can reach it now, and in the new network you still can.)
  • Dark grey is the area that you can no longer reach in that time.  You can see a little of this on the east edge of the city centre, and around Malahide in the north.  (Yes, I know this looks too much like the light grey of the parks and bay, but if you look close you’ll notice the difference.  There are good but boring technical reasons[1] why we didn’t have a free hand in choosing colours.)
  • Light blue is the area that you can newly reach under the new network.  You can’t get to these places in 60 minutes now, but under the proposed network, you can.
  • The box “How Many Jobs Can I Reach?” shows you that the light blue area, minus the dark grey area, amounts to an increase in 1/3 in the number of jobs (and student enrolments) that you can get to in an hour.  We show these because there’s good data on where they are, but obviously this gives you a sense of your ability to get to all kinds of useful things: shopping, social opportunities, etc etc.

Want to dig deeper into these calculations?  See Chapter 8 of our full report.

Across all of Dublin, the average person can go 20% farther (i.e. to 20% more jobs and student enrolments, and thus other useful places) in 30 minutes.  But this tool shows you what that result is for any location, and where.

Many people have asked us for “travel time maps”.  That’s what this tool is.  Compare the 30, 45, and 60 minute results, and you’ll get a good sense of how long it will take to get somewhere, and whether that changes.

And yes, this is the midday outcome, which is usually also the outcome for the early evening and weekend.  Doing this calculation for the peak rush hour raises several difficulties [2].   The outcome will usually be the same in direction (positive or negative in the jobs reachable), though sometimes not as dramatic in the degree of change.  For outer suburban areas, peak express services may be proposed that give better outcomes than shown.

“Show Routes”

How would you get to those places?  The “Show Routes” tool shows you the proposed network with the high-frequency network highlighted in red, because it’s especially likely that a logical trip will go via those routes.  Note the frequency legend that appears in the lower right.

Roll over any route (like we did for the route serving Priorswood here).  It tells you that this is Route A1 and the yellow highlight shows you everywhere that A1 goes.  Now, it’s not hard to see how you’d go to another part of the city, because you can see where A1 crosses other routes going in your desired direction, and you can roll over them to see what they do.

Many people have asked us for a before-and-after trip planner, giving exactly how a trip would go before and after the change.  We are sorry we can’t provide that, but you can get most of that information from exploring this tool.  First, the “Where Can I Go?” tool will show you, pretty closely, what a travel time will be from any point to any other, and then the “Show Routes” tool will show you the network.  Follow the brightest lines (the most frequent services) that seem to go where you’re going.  That’s usually the fastest path.

 

Footnotes:
[1] Our tool required us to choose colours such that the “no longer reachable” and “newly reachable” colours add up to the “still reachable” colour, while still providing adequate contrast.  This turns out to be harder than it sounds.
[2] In short, the midday service pattern (which is also the pattern of much of the evening and weekend) remains the same for several hours, so we can coherently talk about a typical condition.  The peak service pattern, by contrast, is changing every minute, so the facts about how long a trip takes are also changing continuously.  The result of a peak analysis would therefore be hard to present as a general outcome that would describe most people’s experience.  (A peak analysis would also require making many more assumptions that would make the outcome less reliable.)  In general, peak results will be similar to midday results in direction (positive or negative) but may be less dramatic in the degree of change.

 

Is Ride-Hailing to Blame for Rising Congestion?

Throughout the past few years, the explosive growth of ride-hailing services such as Uber and Lyft have changed the landscape of urban transportation.  Proponents of ride-hailing have long argued that these services benefit cities by reducing the need for people to own their own cars and by encourage them to use other transportation options, ultimately reducing the total vehicle miles driven in cities.

Last week, a new report by Bruce Schaller suggests that these ride hailing services are in fact, adding to overall traffic on city streets, and risk making urban cores less desirable places to live. Notably, Schaller’s report finds that:

  • TNCs added 5.7 billion miles of driving in the nation’s nine largest metro areas at the same time that car ownership grew more rapidly than the population.
  • About 60 percent of TNC users in large, dense cities would have taken public transportation, walked, biked or not made the trip if TNCs had not been available for the trip, while 40 percent would have used their own car or a taxi.
  • TNCs are not generally competitive with personal autos on the core mode-choice drivers of speed, convenience or comfort. TNCs are used instead of personal autos mainly when parking is expensive or difficult to find and to avoid drinking and driving

Schaller points out that on balance, even shared rides, offered by Lyft Line and Uber Pool, add to traffic congestion.

Shared rides add to traffic because most users switch from non-auto modes. In addition, there is added mileage between trips as drivers wait for the next dispatch and then drive to a pickup location. Finally, even in a shared ride, some of the trip involves just one passenger (e.g., between the first and second pickup).

To many readers, Schaller’s report implies that Uber and Lyft are primarily to blame for the increasing traffic congestion and declining transit ridership in many US cities.  Citylab published a rebuttal to Schaller’s report, titled “If Your Car Is Stuck in Traffic, It’s Not Uber and Lyft’s Fault”.  The author, Robin Chase, founder of Zipcar, disputes the scale of ride-hailing’s impacts on traffic congestion in cities.  Chase writes:

[In major urban areas], taxis plus ride-hailing plus carsharing account for just 1.7 percent of miles travelled by urban dwellers, while travel by personal cars account for 86 percent.

Chase contends that traffic congestion is not a new problem in cities and that ride-hailing is no more responsible for it than the personal automobiles that still make up the majority of trips.

Special taxes, fees, and caps on ride-hailing vehicles are not the answer. My strong recommendation for cities is to make walking, biking and all shared modes of transit better and more attractive than driving alone—irrespective of the vehicle (personal car, taxi, or autonomous vehicle). Reallocate street space to reflect these goals. And start charging all vehicles for their contribution to emissions, congestion, and use of curbs.

On taxing or limiting all vehicles — called (de)congestion pricing — Chase is right on the theory and Schaller’s report doesn’t disagree.  From Schaller’s report:

Some analysts argue for a more holistic approach that includes charges on all vehicle travel including personal autos, TNCs, trucks and so forth, paired with large investments to improve public transit.  This is certainly an attractive vision for the future of cities and should continue to be pursued. But cordon pricing on the model of London and Stockholm has never gone very far in American cities. Vehicle mile charges have been tested in several states, but implementation seems even further from reach.

Yes, ideally, we would aim to charge every vehicle for precisely the space it takes up, for the noise it creates, and for the pollution it emits, and to vary all that by location and time-of-day. However, we have to start with what’s possible.

Ultimately, the most scarce resource in cities is physical space, so when we allow spatially-inefficient ride-hailing services to excessively grow in our densest, most urban streets, we risk strangling spatially efficient public transit and fueling a cycle of decline.  If we are to defend the ability to move in cities, we have to defend transit, and that means enacting achievable, tactical policies even as we work on building the coalitions needed for bigger change.  Reasonable taxes or limitations on TNCs are one such step.

Finally, these interventions should really be locally-focused, because like all urban transportation problems, this one is extremely localized.  Lyft wants us to think of them as feeders to transit, which is a fine idea.  But what is actually profitable to TNCs is to swarm in the densest parts of cities, increasing congestion and competing with good transit, and that’s where they do net harm.  Lyft and Uber knows where every car is at every moment, so it would be perfectly possible to develop cordon-based surcharges to focus any interventions on the actual problem.  Otherwise, it will be easy to say that by restricting TNCs in Manhattan we’re keeping someone in outer Queens from getting to the subway, which is not the point at all.

Christopher Yuen and Jarrett Walker

The Absurdity of Counting Bus Routes

When presenting a plan, I’ll sometimes be asked to count bus routes.  How many bus routes change in the plan?  How many bus routes still go into the urban core?

These questions have nothing to do with the quality or quantity of transit service.  They have nothing to do with anyone’s ability to get anywhere, or even with how much the service is changing.  The number of bus routes measures one thing only: the complexity of the service.

Here’s how this works:

A bus route is a path followed by some number of buses during the day.  A route may be followed by one bus a day or by a bus every two minutes; either way, it counts as one route.

The number of bus routes can also be changed by how they are named or numbered.  Say a bus route is mostly the same but has a branch on one end, where some buses go one way and some go the other. Is that one bus route or two?  The answer to that question changes the number of bus routes, even though the service itself is identical in either case.

If you want to talk about service quantity, the correct unit is service hours (or service km), where this means one bus operating in service for an hour (or km).

Why count bus routes then?  Only if you are making a point about complexity.  The number of routes in a network is a measure of how complicated the service is.  In this post, for example, I show how a three-route system gets everyone where they’re going faster than a nine-route system, with the added benefit that three routes are easier to keep in your head than nine.

In our Dublin bus network redesign proposal, the number of routes goes from 130 to about 100.  Stated in isolation that sounds like a service cut, when in fact we are just running more buses on simpler routes.  We are expanding service, and making it more useful, by reducing complexity.  Practically nobody is losing service; most people are seeing a measurable improvement

The more routes a system has, the more complexity you have to remember.  Spreading a service budget across more routes also means those routes are less frequent and therefore less useful.

And again, the real measure of a network plan is where people can get to in a reasonable amount of time.  In the Dublin proposal, for example, the average Dubliner can get to 20% more jobs (counting student enrolments) in 45 minutes.  That’s a real expansion in the liberty and opportunity that people experience in their daily lives.  Are you sure the number of bus routes matters more than that?

 

Dublin: How Much Could the Draft Network Change?

While our Dublin network redesign is open for public comment, I’ll be posting some frequently asked questions here.

How much change could we make to the plan in response to public comment?

In a July 18 article in the Irish daily The Independent, Paul Melia wrote that “Only minor changes can be made to a radical restructuring of the Dublin Bus network unveiled last week or it will “fall apart”.  The headline is “Only ‘minor changes’ can be made to radical plan for Dublin Bus.”

“Minor” is the reporter’s word, not mine.  I did say that if you change more than about 15% of the network it will fall apart.  But 15% is not minor.  While the plan is a dramatic change, at least half of it consists of service on streets served now, doing something much like what it does now.  So compared to the amount of the network we’re actually changing, 15% is very substantial.

Under the plan, 77% more people can get to DCU in 45 minutes, and someone living near there can get to 44% more jobs in that time. (You can find these for many point around Dublin at busconnects.ie)  But this isn’t the result of certain routes. It’s the result of a whole network of connections involving many possible routes you could use.

Why is there a limit to how much we could change the network?

The defining feature of a network the interdependence of its parts.  We did not just design a set of routes.  We designed a pattern of connections.  The connections, as much as the routes, governs how much of Dublin people can get to in a reasonable amount of time.  So we will resist changing a route in a way that destroys or damages a connection, because the connections — the ease of getting off this bus and onto that one so that you can get to more places — are the essence of how the plan achieves its benefits.

Having said that, we will make changes.  Quite possibly lots of them.  But we will be mindful of this principle when we do.