How to Design Rail Service to Connect to Buses Better

Usually, integrated transit planning means designing bus networks to feed rail trunks better. Buses are mobile: their routes can move based on long-term changes in the city’s physical and economic layout. Railroads in contrast have high installation costs. Between the relative ease of moving buses and the fact that there’s a hierarchy in which trains are more central than buses, buses normally should be feeding the trains. However, there are some cases in which the opposite happens: that is, cases in which it’s valuable to design rail infrastructure based on expected bus corridors. Moreover, in developed and middle-income countries these situations are getting more rather than less frequent, due to the increasing use of deep tunneling and large station complexes.

In nearly every circumstance, the hierarchy of bus and rail remains as it is; the exceptions (like Ottawa, at least until the light rail subway opens) are so rare as to be notable. What I posit is that in some situations, rail infrastructure should be designed better to allow buses to feed the trains more efficiently. This mostly affects station infrastructure, but there are also reasons to choose routes based on bus feeding.

Major bus corridors

Surface transit likes following major streets. Years ago, I blogged about this here and here. Major streets have two relevant features: they are wide, permitting buses (or streetcars) to run in generous dedicated lanes without having to deal with too much traffic; and they have continuous linear development, suitable for frequent bus stops (about every half kilometer).

These two features are likely to remain important for surface transit for the foreseeable future. The guidelines for good surface transit service depend on empirical parameters like the transfer penalty (in particular, grids are not the universal optimum for bus networks), but major corridors are relatively insensitive to them. The walk penalty can change the optimal bus stop spacing, but not in a way that changes the basic picture of corridor-based planning. Which streets have the most development is subject to change as city economic and social geography evolves, but which streets are the widest doesn’t. What’s more, a train station at a street intersection is likely to cement the cross-street’s value, making adverse future change less likely.

Note that we don’t have to be certain which major streets will host the most important buses in the future. We just need to know that major buses will follow major streets.

The conclusion is that good locations for rail infrastructure are major intersecting streets. On a commuter line, this means stations should ideally be placed at intersections with roads that can carry connecting buses. On a subway line, this means the same at a more local scale.

Stations and accessibility

When possible, train stations should locate at intersections with through-streets, to permit efficient transfers. This also carries over to station exits, an important consideration given the complexity of many recently-built stations in major rich and middle-income cities.

It goes without saying that a Manhattan subway line should have stations with exits at 72nd, 79th, 86th, 96th, etc. streets. Here, Second Avenue Subway does better than the Lexington Avenue Line, whose stations are chosen based on a 9-block stop spacing and miss the intersecting buses.

However, it’s equally important to make sure that the accessible exits are located at major streets as well. One bad example in New York is the Prospect Park B/Q station: it has two exits, one inaccessible on Flatbush Avenue and one accessible on Empire Boulevard. In theory both are major corridors, but Flatbush is far and away the more important ones, one of the busiest surface transit corridors in the city, while Empire competes for east-west buses with Kings County Hospital, the borough’s biggest job center outside Downtown Brooklyn. Eric Goldwyn’s and my Brooklyn bus redesign breaks the B41 bus on Flatbush and loops it and the Washington Avenue routes around the station complex to reach the accessible exit.

The Prospect Park case is one example of an almost-right decision. The full-time, accessible exit is close to Flatbush, but not quite there. Another example is Fields Corner: the eastern end of the platform is 80 meters from Dorchester Avenue, a major throughfare, and 180 meters from Adams Avenue, another major street, which unlike Dot Ave diverges from the direction the Red Line takes on its way south and is a useful feeder bus route.

Commuter rail and feeder buses

The station placement problem appears especially acute on mainline rail. This is not just an American problem: suburban RER stations are built without regard for major crossing roads (see, for example, the RER B airport branch and the RER A Marne-la-Vallee branch, both built in the 1970s). Railroads historically didn’t think much in terms of systemwide integration, but even when they were turned into modern rapid transit, questionable stop locations persisted; the Ashmont branch of the Red Line in Boston was taken over from mainline rail in the 1920s, but Fields Corner was not realigned to have exits at Dot and Adams.

Today, the importance of feeder buses is better-understood, at least by competent metropolitan transportation planners. This means that some stations need to be realigned, and in some places infill stops at major roads are desirable.

This is good for integration not just with buses but also with cars, the preferred station access mode for American commuter rail. The LIRR’s stations are poorly located within the Long Island road network; Patrick O’Hara argues that Hicksville is the second busiest suburban station (after Ronkonkoma) not because it preferentially gets express service on the Main Line, but because it has by far the best north-south access by road, as it has one arterial heading north and two heading south, while most stations miss the north-south arterials entirely.

Instead of through-access by bus (or by car), some stations have bus bays for terminating buses. This is acceptable, provided the headways are such that the entire local bus network can be configured to pulse at the train station. If trains arrive every half hour (or even every 20 minutes), then timed transfers are extremely valuable. In that case, allowing buses to stop at a bay with fast access to the platforms greatly extends the train station’s effective radius. However, this is of far less value on a dense network with multiple parallel lines, or on a railroad so busy that trains arrive every 10 minutes or less, such as the RER A branches or the trunks of the other RER lines.

Within New York, we see this mistake of ignoring local transit in commuter rail planning with Penn Station Access. The project is supposed to add four stations in the Bronx, but there will not be a station at Pelham Parkway, the eastern extension of Fordham Road carrying the city’s busiest bus, the Bx12. This is bad planning: the MTA should be encouraging people to connect between the bus and the future commuter train and site stations accordingly.

Street networks and route choice

On a grid, this principle is on the surface easy: rapid transit routes should follow the most important routes, with stops at cross streets. This is well understood in New York (where proposals for subway extensions generally follow busy bus routes, like Second Avenue, Nostrand, and Utica) and in Vancouver (where the next SkyTrain extension will follow Broadway).

However, there remains one subtlety: sometimes, the grid makes travel in one direction easier than in another. In Manhattan, north-south travel is easier than east-west travel, so in isolation, east-west subways connecting to north-south buses would work better. (In reality, Manhattan’s north-south orientation means north-south subways are indispensable, and once the subways exist, crossing subways should aim to connect to them first and to surface transit second.) In West Los Angeles, there is a multitude of east-west arterials and a paucity of north-south ones, which means that a north-south subway is of great value, connecting not just to the Expo Line and upcoming Wilshire subway but also other east-west arterials carrying major bus routes like Olympic.

Moreover, some cities don’t have intact grids at all. They have haphazard street networks, with some routes suitable for arterial buses and some not. This is less of an issue in mature cities, which may have such street networks but also have older subway lines for newer route to connect to, and more in newer cities, typically in the third world.

The tension is that very wide arterials are easier to build on, using elevated construction or cut-and-cover. If such a technique is feasible, then constructibility should trump connections to buses (especially since such cities are fast-changing, so there is less certainty over what the major future bus routes are). However, if deep boring is required, for examples because the arterials aren’t that wide, or the subway must cross underwater, or merchant opposition to cut-and-cover is too entrenched, then it’s useful to select routes that hit the arterials orthogonally, for the best surface transit connections.


In a working transit city, rail should be the primary mode of travel and buses should be designed to optimally feed the trains. However, this does not mean rail should be planned without regard to the buses. Train stations should be sited based not just on walk sheds and major destinations but also planned bus connections; on an urban rapid transit system, including S-Bahn trunks, this means crossing arterial streets, where buses typically run. Moreover, these stations’ exits should facilitate easy transfers between buses and trains, including for people with disabilities, who face more constrained mobility choices if they require elevator access. In some edge cases, it may even be prudent to select entire route construction priorities based on bus connections.

While choosing rail routes based on bus connections seems to only be a real issue in rare circumstances (such as the West LA street network), bus-dependent station siting is common. Commuter train services in general are bad at placing stations for optimal suburban bus connections, and may require extensive realignment and infill. On urban subways, station placement is important for both accessibility retrofits and new projects. Outside city centers, where dense subway networks can entirely replace surface transit, it’s critical to select station sites based on maximum connectivity to orthogonal surface lines.


  1. Untangled

    Toronto is the gold standard for this in North America. They have some very frequent routes that connect to subways stations there. Some are so frequent (like every < 10 minutes) it's actually very surprising given that it's all single-family home strip mall suburbia.

    • Alon Levy

      Yep, Toronto has very good station siting on the subway. On GO, it’s a disaster, and they’re only tepidly looking at infill stations.

    • Brendan Dawe

      IMO US urbanist circles put an overemphasis on form and density as a driver of ridership, but they aren’t as explanatory as they would seem. Canadian cities get a higher level of ridership all form being equal thanks to more expensive gas, fewer freeway miles, and lower levels of hostility to public service.

  2. Andy Thompson

    One thing that you consistently fail to address is the subsurface easement issue and the sheer cost of purchasing land above a subway or similar. That is the primary reason subways follow roads especially in the US where the Local DOT owns the streets and the Transit Agency gets to use that “public easement for free”. Look at East aside Access as an example. There was supposed to be an exit on 48th St. but with Chase on one side and the Rudins on the other negotiating an easement to put an entrance through the building was going to cost around $100m despite the fact that the value of their properties and the rents would increase. Of course the obvious answer is to close 48th st as a Through st and bring the entrance up in the street placing lost of bus stops on Madison to piss Chase off and block Jamie Dymons private car park entrance. Other cities have similar issues so while many planners probably know what’s best when you retrofit new facilities into an old infrastructure there will always be compromises to get the project moving and face lawsuit after lawsuit for loss of use. I mean eminent domain does have its limitations.

    • IAN Mitchell

      I don’t think he failed to address that:
      “very wide arterials are easier to build on, using elevated construction or cut-and-cover. If such a technique is feasible, then constructibility should trump connections to buses”

    • Michael James

      to piss Chase off and block Jamie Dymons private car park entrance

      As you imply the MTA does actually have considerable power if it deployed it appropriately. (In a diversion let me say it is why I approve of the occasional transit strikes–typically once a year–in Paris; it lets everyone know in a way they cannot ignore of how much the city depends on them.)
      But when a DINO governor appoints the likes of Joe Lhota as chief of the MTA, don’t hold your breath on any move to disturb, in the slightest way, the powerful especially in the very same world of finance he wants to thrive in.

        • Michael James

          Well, at least Andy Byford has rapid-transit in his blood*, though I don’t really know if his CV is particularly shiny (Sydney, for example, doesn’t shine; was he running it when they had the decade-long farecard fiasco, and like London it has become quite expensive. London doesn’t impress me and I don’t know about Toronto.) I shouldn’t be lookist but I am immediately suspicious of that shaven-headed hardman look. Perhaps he is the hardman who bulldozes thru the intractable problems … or he is merely a professional manager who slides thru these positions (by giving “good slide”…shows) with no apparent reason for his rise (a main feature of modern managerialism and half the cause of dysfunction in so many things). As is so obvious, the cause of 99% of the MTA’s problems is chronic under-investment over half a century, and he wants $40 billion to fix it all. Doh! So it really comes back to the politicians and who has confidence in Cuomo, and his placeman Republican politician-on-the-make and econo-rationalist Joe Lhota who remains Chairman (a powerful position that can block or do end-runs around any reform; he is a lifelong New York politician-business toady who will surely “manage” Byford in his spare time (which is all he devotes to the MTA)).

          It is change at the top that is required. You shoulda voted for Miranda (Cynthia)! And I am deadly serious. If you can have Trump for President ….

          *Not exactly. His primary training was in languages (French & German!). I suppose we should be grateful it isn’t the usual: economics or MBA etc. and a redbrick uni not Oxbridge. But also: “a diplôme supérieur d’études françaises from the Université de Pau et des Pays de l’Adour.” So maybe some hope after all! Whaddya think, Alon … (polish up your French and maybe you can rustle up a job in the Big Apple if you really want to swap mega-cities).

          • Alon Levy

            In Toronto people believe Byford to have been a success. An extremely costly subway extension got somewhat less expensive under his tenure, for one.

            Also, I really would not call Lhota an econo-rationalist. He’s a crony. He’s there to do nothing and to piss off de Blasio. I know you hate it when I say it, but Macron is probably one of the two best examples of an econo-rationalist in power today, the other being Merkel. They’re not here to make the working class feel empowered. They’re here to make sure their respective countries’ economies grow. Macron’s version is somewhat gentler than Merkel’s austerity, and rhetorically Macron tries to be more interesting with his Jupiter comment, but fundamentally they’re very similar. They’re here to run the show, they make reforms they think necessary without rocking the boat too hard, they’re both actually competent administrators, and neither has much use for ideology or partisan political competition.

          • Michael James

            Alon Levy, 2018/10/22 – 23:16

            You may be correct about Lhota. Certainly correct about him being a crony. Perhaps not an econo-rationalist but then none of these guys are in their personal life, they just use it as a tool to achieve certain ends in their professional lives.

            Re Macron, I think you have it perfectly wrong, and are confusing competent administrators using rational economic and management principles, with economic-rationalism. The latter is when an economic argument is the be-all and end-all of any argument of any decision process, especially for public spending. Pure numbers, indeed it is a kind of numerology and its practitioners love Cost-Benefit-Analyses regardless of validity of parameters because it delivers such a clear-cut binary result with which they proceed to cosh any opponents over the head. It is why I am not being a hypocrite when lauding French so-called elite grads of their grands ecoles; obviously they are highly trained in all the same things as anywhere else (better if judged by their competence in running things like public transport, building stuff etc) but I’m not sure economic-rationalism is consistent with being French (I can hear people saying … but .. Descartes …). I don’t recall hearing much about CBAs in France or French decision making, yet of course it is done at a fundamental level, just not at numerology level. And yes, you are a bit prone to this method.

            Merkel is no longer anyone I can comprehend. At first I had great hopes–stupidly I thought that, with her PhD in a ‘hard’ science, that she was “one of us”. But she has made so many fundamentally bad decisions that she is the major impediment to the entire EU project. I simply don’t understand her popularity (of course strictly amongst Germans) but suppose it is some yearning for a strict mother figure, a protector with a firm hand of discipline, blah blah (yes, alas, shades of Maggie). Though it was done very stealthily she has imposed what most should dread: the iron control of German rigid philosophy over all of Europe. I don’t know if it is her but certainly economic-rationalism, married to German superiority complex, was the guiding light of her treasurer Wolfgang Schäuble (almost a Dr Strangelove caricature!). The Germans are very prone to its appeal, you know, all that perfect engineering etc (Vorsprung durch Technik) which many still convince themselves is the total explanation of their success. While the reality is that Germany has unfairly benefited from the original fix of the Euro (no accident that the ECB is in Frankfurt–it was the non-negotiable condition imposed by Germans on the French). They are sucking the lifeblood out of much of Europe. But it’s not clear to me that Merkel quite understands or sees any of this. The austerity imposed on others and the damage it is doing, and the awfulness of her unilateral action on refugees is neither helping the wider refugee problem even as it helps create a toxic far-right reaction all over Europe. Before the last election I said it would be terrible, certainly for the EU, if she were to return as leader (term limits, anyone?) and here we are with an indecisive Germany and the CSU losing most of its supporters in Bavaria, half to the far-right, half to the Greens, which at least is a rational (sic) reaction IMO. Despite winning so many elections she strikes me as not much of a leader and I can’t discern any vision.

            I genuinely don’t know if Macron is the saviour of France (in as much as it needs saving! it looks like paradise compared to most of the world including or especially the Anglosphere), let alone Europe, but I know for a certainty that Merkel is not, and she needs to be gone. I’d give Macron the benefit of the doubt, certainly for France but also for the EU (who the heck else is there?). He’s a rationalist but not a braindead econo-rationalist.

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  5. Phake Nick

    What should be the minimum frequency of feeder buses for people to feel convenient using it if the train is at metro level high frequency service?

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