There are recurrent discussions of how to best connect public transportation to airports; I, too, have made my comments both on how desirable such connections are and how to best build them. What I think is less discussed is how to build airports in a way that makes it easier to serve them by public transit. Airport authorities spend billions every few decades rebuilding terminals, sometimes even moving the entire airport to a new location, but they never consider how to do so in a way that makes transit access the easiest; this means airport access is done by car, or another high-cost scheme must be implemented to bring a rail line to the airport. Now that there is a plan to replace the Newark AirTrain for a billion dollars, just twenty years after it was first built, it’s worth discussing what capital projects on the airport side should facilitate transit access.
First, recall from previous discussions on this blog that the best way to serve a major international airport is by a mainline train, which is capable of both providing fast service to the CBD (where most inbound air travel is headed) and to many suburbs (which have outbound travelers).
However, we can say more: it is better, other things being equal, for the airport to be on the way, rather than at the end of a line. If the airport must be at the end of a line, it should not be far from where the line would’ve ended if the airport were not there. For example, LaGuardia is a few kilometers east of the end of the Astoria Line, which can be extended. Vancouver’s airport is on a short branch of the Canada Line, which would have been built to Richmond Centre even without the airport.
An even better example would have been Floyd Bennett Field, just past where the Utica subway should end; there were plans in the 1930s to build such a subway, but not only were they never realized, but also Mayor LaGuardia preferred to build the airport that currently bears his name, for easier auto access to Manhattan than Bennett Field had. Thus we can catalog the decision to open the new airport and close Bennett Field as bad for transit access, and oppose similar moves when cities today propose them. The best location for an airport, from the point of view of transit access, is near a subway or commuter rail station, ideally close enough that no further people mover is required.
Let us now discuss internal airport design. I claim that, to maximize transit accessibility, airports should have just one terminal (or several terminals that can be served from the same station), or, failing that, one dominant terminal, as at such fortress hubs as Detroit, Frankfurt, and Charles-de-Gaulle. The reason is that trains are slowed down by additional stations, whereas cars are not slowed down by additional bays and driveways. Mainline trains, in particular, rarely make more than one stop at an airport, and in the cases I know of where they do, the airport is at the end of a branch (such as the RER B and the lines serving Narita), rather than on the way.
This introduces some tension into airport design. Large airport terminals are dendritic, to maximize the perimeter available for gates and jetways; in some cases, they feature satellite terminals, connected to the main terminal by underground passageways, people movers, or even landside buses (as at Charles-de-Gaulle). I encourage people to look at satellite images of Frankfurt, O’Hare, Atlanta, Zurich, and Charles-de-Gaulle. Frankfurt’s Terminal 1 is a kilometer from entry to the farthest branches to the west. This creates some demand for quicker small terminals, which are harder to serve by rail. In addition, the most efficient dendritic design has branches coming out from the center in every direction, except perhaps one direction for an access road; this makes it harder to be on the way of a rail line.
I think it is telling that the single- or dominant-terminal design is less common at airports that are not a single airline’s fortress hub. Haneda and Narita have two major terminals each, one used by Japan Airlines and one used by ANA. Madrid has four terminals, one for Iberia and three connected ones, sharing a Metro station, for competitors, including several low-cost airlines. In all three cases, there are two train stations per line connecting to the airport (with the understanding that Narita has multiple lines, operating by competing railroads).
Usually, airports make an effort to group airlines by alliance. Thus Charles-de-Gaulle and Frankfurt put their respective dominant airlines and partners in their main terminals, and competing airlines in smaller terminals; and Narita makes sure to group Star Alliance airlines with ANA and Oneworld airlines with JAL. Among the largest airports of Europe, Heathrow is the big exception, since it organizes terminals by alliances but splits Oneworld between Terminal 5 for British Airways and Terminal 3 for the rest.
In the US, this is not common, with some exceptions such as Detroit and JFK’s Terminals 7 and 8. This is because the US does not permit connecting air passengers to transit its airports. All passengers arriving at a US airport from a foreign airport without preclearance, even ones in transit, have to go through immigration, collect their bags, go through customs, recheck their bags, and go through security again; between the inconvenience and the real risk of literally being disappeared, few people connect in the US between two foreign countries. Hub terminals elsewhere facilitate easy transfers by maintaining large international areas where passengers can walk between gates, and keeping the passport controls between the international and domestic terminals short. Regardless, even with the vagaries of American immigration policy, it is easier to connect without having to go between terminals; moreover, for passengers leaving the US rather than arriving, the situation is if anything easier than in Europe since there’s no passport control at exit.
Let us now apply these concepts to New York’s two main international airports. Newark may be a fortress hub, but it is not configured as one; United and its Star Alliance partners are sprawled across all three terminals. Moreover, the terminals are just far enough from the commuter rail station to require a people mover. Since it’s better for an airport to be on the way, and have just a single terminal, what this suggests is that Terminal C should be lengthened to approach the train station.
There is currently a plan to replace Terminal A, for $1-1.25 billion of construction budget and $2 billion total development budget. Under this single-terminal paradigm, the terminal should not be redeveloped. Instead, it should be demolished, and replaced by extensions of Terminal C to the west, with additional concourses and piers both to the north and to the south, replacing the current road loop serving the terminals. People would arrive by road via US 1 or by rail via the commuter rail station. Security checkpoints would be conducted at a building just west of Route 1, and the airside terminal’s western end would be an overpass over the road. Rail passengers would have enclosed overpasses to the checkpoints; there would not be any need for a people mover, only moving walkways given the distance between the station and the terminal’s current eastern end. There is enough space for the new concourses to also replace Terminal B, which is of similar vintage to Terminal A.
At JFK, the situation is different. First, it is not a fortress hub. Its top three carriers – JetBlue, Delta, and American – are all reasonably happy with their terminals (Delta’s terminal is 4, not 2, which it is abandoning). British Airways is considering abandoning Terminal 7 and joining American at Terminal 8. Consolidating the airlines that use Terminal 1 at Terminal 4 is impossible until the US resolves its endless immigration lines, which at Terminal 4 are often longer than an hour.
Second and more fundamentally, the transit access situation there is good enough. JFK is far from any subway or commuter rail line, so the only way to serve it by rail is by a dedicated people mover, of which the AirTrain is not bad. The connection to Jamaica approaches the “be on the way” maxim well, since Jamaica is central to the LIRR network and has fast service to Manhattan on the subway as well. Some transit advocates in the region periodically propose a direct subway or commuter rail line to replace the AirTrain connection, but such plans always run against network design issues, since the branching is set up in a way that reduces frequency to Jamaica, a more important station. Given that there must be some people mover connection, traveling in a circle among the terminals is not terrible; straightening the route has some benefits, but the cost of rebuilding the infrastructure is almost certainly too high to be justified.
Update: James Sinclair argues convincingly that the Newark AirTrain is not really at the end of its life, but Port Authority is saying that to justify spending billions of dollars on a better replacement, including either a PATH extension to the airport station (which is largely dead) or an extension of the AirTrain to Newark Penn Station, as a sweetener for United.