Is line numbering just a geeky obsession – or a crucial form of messaging?

How did these buses get their numbers? Image: Roman Pavlyuk/Wikimedia.

Q: How do professionals assign line numbers?

A:  Much as geeky amateurs do, when drawing imaginary networks.It's a process of (1) imagining beautiful systems of order, and (2) willing them in to being. 

Unfortunately, real-world professionals have to proceed through the additional steps of (3) clashing with proponents of competing systems, (4) enduring the derision and sabotage of anarchists, and finally (5) resigning to a messy outcome where only traces of beauty remain – visible "between the lines" so to speak, for those still capable of enchantment.

All this is visible, for example, in a slice of the bus network in San Francisco:

San Francisco's bus map, c2010. Image: SFMTA.

Look at the numbers of the east-west lines, from top to bottom. Focus on the right part of the image between Fillmore and Van Ness avenues, where the pattern is clearest.  The sequence is:  1, 2, 3, 38, 38L, 31, 5, 21, 6, 71. 

Here, obviously, is a kind of Parthenon of line numbering, a ruined but still recognisable system of order. At one time, starting with Line 1 and proceeding south, there was a series of lines numbered 1, 2, 3, 4, 5, 6, 7, in more-or-less geographical order.  The numbers 31, 38 and 71 were added later, by those anarchists I mentioned.  Since that map was made, with Neoclassical visionaries back in charge, line 71 has been renumbered back to 7, restoring a bit of the previous order. 

The number 21 is a trace of a different system of order.  Originally, the one-digit numbers referred to lines that flow into downtown, mostly along Market Street, while the 20-series referred to lines that cross Market, generally running perpendicular to the first group.  The north-south lines 22 and 24 in this image still tell that story, and as I understand it, the 21 used to flow across Market – but it was revised long ago to flow into Market and thus ruin the beautiful pattern.

Line numbering, in short, is really a dialogue between three impulses:

1.     Grand Synthesizing Visionaries, who imagine schemes where each number will not just refer to a line, but reveal its exact position and role in the network.  For example, these visionaries may think up schemes that recall the patterns of numbered streets and avenues in many North American cities, or the similar numbering of the US Interstate system.

2.     Anarchists, who need a number for a new line, don't care about the vision, and pick whatever number comes to mind. 

3.     Conservatives, who believe that once a line number is assigned it should never be changed, no matter how offensive it may be to the Visionaries.  Conservatives are responsible for the permanence of various reckless numberings made by Anarchists over the years.

Of course, there are really four or more characters in the dialogue, because there's usually more than one Visionary – and Visionaries, by their nature, prefer their own visions to other people’s.

The most common vision of line numbering is to categorize lines by location.  In small networks of lines all radiating from a point, it's common to see numbers assigned sequentially going around the circle.  In Portland, for example, these radial lines used to be numbered clockwise starting with North Portland; very astute eyes can still see traces of that largely ruined pattern. 

Networks that have always been grids will sometimes be numbered according to the grid pattern.  Thus, for example, a quick glance at the Las Vegas network map shows that the east-west lines, in order from south to north, are 201, 202, 203, 213, 204, 206, 207, 215, 208, 209, 210, 211, 218, 219 – a reasonable effort to hold back the anarchists.

I started out life happy to number lines in geographical order, but over time I've realised that people need to understand what kind of service a line provides even more than they need to know where it goes.  So I generally advocate line numbering systems that reflect crucial distinctions in either:

  • frequency and span (is the service running when I need it?) or 
  • rapid vs local stopping pattern (is the service designed to be ridden long distances or short ones?)

For example, I always recommend a numbering scheme for peak-only commuter express services that distinguishes them from any all-day services in the same area:. That’s because peak service tends to be more complex than all-day service, and can therefore tend to obscure it, whether on a map or on a numerical list of lines.  

But above all, line numbering is a lesson in the impermanence of all things – and especially of visions of the perfectly ordered city.

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, which you can buy here.

This article was originally written for his blog in 2010, and is reposted here with permission. 


What's actually in the UK government’s bailout package for Transport for London?

Wood Green Underground station, north London. Image: Getty.

On 14 May, hours before London’s transport authority ran out of money, the British government agreed to a financial rescue package. Many details of that bailout – its size, the fact it was roughly two-thirds cash and one-third loan, many conditions attached – have been known about for weeks. 

But the information was filtered through spokespeople, because the exact terms of the deal had not been published. This was clearly a source of frustration for London’s mayor Sadiq Khan, who stood to take the political heat for some of the ensuing cuts (to free travel for the old or young, say), but had no way of backing up his contention that the British government made him do it.

That changed Tuesday when Transport for London published this month's board papers, which include a copy of the letter in which transport secretary Grant Shapps sets out the exact terms of the bailout deal. You can read the whole thing here, if you’re so minded, but here are the three big things revealed in the new disclosure.

Firstly, there’s some flexibility in the size of the deal. The bailout was reported to be worth £1.6 billion, significantly less than the £1.9 billion that TfL wanted. In his letter, Shapps spells it out: “To the extent that the actual funding shortfall is greater or lesser than £1.6bn then the amount of Extraordinary Grant and TfL borrowing will increase pro rata, up to a maximum of £1.9bn in aggregate or reduce pro rata accordingly”. 

To put that in English, London’s transport network will not be grinding to a halt because the government didn’t believe TfL about how much money it would need. Up to a point, the money will be available without further negotiations.

The second big takeaway from these board papers is that negotiations will be going on anyway. This bail out is meant to keep TfL rolling until 17 October; but because the agency gets around three-quarters of its revenues from fares, and because the pandemic means fares are likely to be depressed for the foreseeable future, it’s not clear what is meant to happen after that. Social distancing, the board papers note, means that the network will only be able to handle 13 to 20% of normal passenger numbers, even when every service is running.

Shapps’ letter doesn’t answer this question, but it does at least give a sense of when an answer may be forthcoming. It promises “an immediate and broad ranging government-led review of TfL’s future financial position and future financial structure”, which will publish detailed recommendations by the end of August. That will take in fares, operating efficiencies, capital expenditure, “the current fiscal devolution arrangements” – basically, everything. 

The third thing we leaned from that letter is that, to the first approximation, every change to London’s transport policy that is now being rushed through was an explicit condition of this deal. Segregated cycle lanes, pavement extensions and road closures? All in there. So are the suspension of free travel for people under 18, or free peak-hours travel for those over 60. So are increases in the level of the congestion charge.

Many of these changes may be unpopular, but we now know they are not being embraced by London’s mayor entirely on their own merit: They’re being pushed by the Department of Transport as a condition of receiving the bailout. No wonder Khan was miffed that the latter hadn’t been published.

Jonn Elledge was founding editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.