For years, Jarrett Walker has been making the point that streetcars do not provide much transportation value over buses. They have higher capacity, because trams can run longer vehicles, but on a medium-ridership bus line without capacity constraints, this is not relevant. As I note in comments, tramways can use rail signaling to get marginal speed advantages, but it’s not a big advantage. They also have slightly lower minimum headways – a single bus route running more often than every 3 minutes will hopelessly bunch, whereas tramways seem capable of higher frequency – but this is again a matter of capacity. And yet, there is an observed rail bias, even when other factors are kept the same: a Transportation Research Bureau report by Edson Tennyson concludes it is 34-43%, using evidence from North American cities in the four decades after WW2. In this post, I would like to propose one mechanism that may produce rail bias even when speed, capacity, and frequency are unchanged.
Low-floor vehicles make it easier to board from raised curbs. Passengers do not need to climb steps as they do on older buses and streetcars, but can walk straight to the vehicle. This speeds up boarding and improves the passenger experience: see p. 14 of a presentation about commuter rail level boarding, p. 64 of a book about low-floor light rail, and a study about bus dwell times in Portland. It’s especially useful for passengers in wheelchairs: as the Portland bus reference notes, the difference between low- and high-floor buses’ dwell times is especially noticeable when there are wheelchair lifts, because operating a wheelchair lift on a low-floor bus is much faster than on a high-floor bus. Low-floor vehicles’ ability to not lose too much time every time a disabled passenger boards or disembarks improves reliability, which in turns allows schedules to be less padded, improving trip times even when no passenger in a wheelchair uses the route.
While high-floor buses and high-floor trains serving low platforms are similar in requiring passengers to climb multiple steps, low-floor buses and trains with level boarding (regardless of whether high or low) are different. Trains run on guideways; they can have the vehicle’s edge exactly level with the platform edge, with narrow horizontal gap. My attempt to measure this on SkyTrain in Vancouver yielded a horizontal gap of about 5 cm, and a vertical gap of perhaps 2 cm; with such gaps, passengers in wheelchairs can board unaided. While SkyTrain is automated rapid transit rather than light rail, nothing about its technology makes the rail-platform gap easier to resolve than on other rail lines.
In contrast, low-floor buses do not have true level boarding. The bus floor is still raised from the curb somewhat, so modern low-floor buses typically kneel, increasing dwell time by a few seconds per stop, to reduce the platform gap. While it’s possible to raise the curbs as at light rail stops, the buses are still buses, and cannot align themselves to be as close to the platform as trains are: without rails, they sway from side to side, so a safety margin is required from the platform edge. As a result, passengers in wheelchairs cannot board unaided without a retractable ramp, which adds considerable dwell time. On board the bus, the more sudden acceleration also requires the wheelchair to be strapped, adding dwell time even further.
Because there is no way to prevent a bus from incurring schedule risk if there’s a passenger in a wheelchair, bus schedules are inherently more vulnerable than train schedules. While few transit passengers are in wheelchairs, passengers who have luggage, walkers, or strollers can get on and off much faster when there’s perfect level boarding, and are slowed by the need to navigate steps or a wide vehicle-platform gap; the schedule will have to take this into account. Low-floor buses reduce this problem, but do not eliminate it.
The limiting factor to bus frequency is not stopping distances, unlike the case of trains. Instead, it is bunching: at very high frequency, small variations in boarding time compound, as fuller buses are harder to board. Soon enough a slightly delayed bus becomes even more delayed as passengers take more time to board, until it bunches with the bus behind it. This effect can be reduced with off-board fare collection, but when the bus is crowded, the combination of narrow passageways and a significant platform gap means that boarding time is nontrivial no matter what.This effect means that all else being equal, a low-floor tramway will be faster and more reliable than a low-floor bus. In practice, all else is not equal, and in particular, in mixed traffic, the bus’s ability to get around obstacles will make it faster. But with well-enforced dedicated lanes, tramways are capable of running reliably with less schedule padding than buses. A familiar experience to North American bus riders – sitting for several minutes as a passenger in a wheelchair boards, and maneuvers awkwardly through the narrow spaces to where the bus driver will strap in the chair – is not an issue on any train with level boarding.
Two years ago, I wrote a post criticizing subway lines that mix radial and circumferential elements. These lines, for examples Shanghai Metro Lines 3 and 6 and New York’s G train before 2001, contain long radial segments, going from an outlying neighborhood toward city center, but then switch to circumferential mode, avoiding city center and instead serving secondary nodes. Such lines do not get high ridership, because they fail at either radial or circumferential transit. Recently, I was challenged in comments about my support for a mixed line that goes in the other direction: circumferential on the outside, radial on the inside. I would like to talk more about such lines.
Consider the following diagram of a subway system:
The city is shown in light gray, with its center in dark gray. There are five subway lines: the red and blue lines are straightforward radials, the green line is a straightforward circumferential, the yellow line mixes radial and circumferential as criticized in my previous post, the pink line mixes radial and circumferential in the other manner, which I will describe in this post.
The reason the yellow line is going to underperform in this system is that it fails as a radial: it does not go to city center, which has the largest concentration of destinations for transit users. People who have equal access to the red and yellow lines, north and south of city center, are much likelier to choose the red line, which takes them where they want to go. The green line fails as a radial too, but has the positive features of a circumferential: it only serves relatively nearby neighborhoods, which are likely to be denser and produce more riders per unit length; it connects to every line in the system; it allows people to connect between two radial lines without going through the congested city center; it has no dominant direction at the peak, so trains are unlikely to be full in the peak direction and empty in the reverse-peak direction. The yellow line has none of these features, unless one wants to connect between the western legs of the blue and pink lines.
The pink line still works as a radial. Its northeastern leg is a straightforward radial, but even its southwestern leg works as a radial for people who live west of the yellow line and wish to commute to city center. In this way, it is not truly a mixture of radial and circumferential elements the way the yellow line is, but is simply a radial with a circumferential element tacked on at the end.
Whether the pink line’s circumferential tail works must be evaluated against two alternatives: build nothing, and build a radial leg. This is because in an incrementally-built transit system, the radial parts of the line are typically built first, and the circumferential tail is tacked on as a later extension. In the no-build case, the pink line’s southwestern leg would simply be shorter than the other radial legs in this system. In the radial case, the pink line’s southwestern leg would look symmetric with the northeastern leg. This depends on the following factors:
- The strength of the radial alternative. If the radial alternative is strong, then this discourages building the circumferential extension, and vice versa. The radial alternative can be weak in several ways: the southwestern quadrant of the city depicted above may be already replete with radial transit and not need more; the population density in the neighborhoods that would be served by the radial option may be low; and the city’s layout may not be the above-depicted perfect circle, so that there is nowhere for the line to turn except sideways.
- The strength of the corridor that would be served by the circumferential leg. The leg can never be a complete circle, so it must be evaluated as a rapid transit line on an individual street or corridor. This far out of city center, transit demand on each route is unlikely to be high, but there may well be exceptions, for example if there is a linear secondary CBD. For example, while Seoul Metro Line 2 is fully circumferential, one of its segments follows a Tehran Avenue, a major street in Gangnam with high transit demand, which would justify a subway even if it weren’t part of a large circle.
- The strength of the circumferential transit demand from the end of the potential circumferential extension to the radial segment. In the depicted city, there may be strong demand for east-west transit south of the CBD, and the circumferential pink line is then better at serving it than connecting between the red and yellow lines via the blue line.
The original impetus for this post, as noted at the beginning, is a comment challenging me for my support of an extension of Second Avenue Subway Phase 2, going under 125th Street from the planned terminus at Lexington Avenue to Broadway, with stations at the intersection with each preexisting subway line. I contend that in this case, all three factors above point to a very strong circumferential extension. In order:
- The radial alternative is to extend Second Avenue Subway to the north, to the Bronx, presumably under Third Avenue, but according to some railfans also under University Avenue. This is problematic, for three reasons. First, the Bronx already has many north-south lines feeding into Manhattan trunk lines, with mediocre ridership. The Manhattan trunk lines are overloaded, but mostly with traffic coming from the Upper East and West Sides, Harlem, and Washington Heights. Second, Third Avenue is close to the Harlem Line, which could be used for local transit if fares and schedules are integrated with the subways and buses. And third, the plan for Second Avenue Subway is for the line to turn west at 125th toward Lexington, since 125th and Second is not as compelling a destination, and this makes it easier to extend the line to the west than to the north.
- 125th Street is a very busy street, and acts as the main street of Harlem. Transit demand is high: four bus routes use the street, with a total of 32,630 boardings per weekday on 125th Street, exclusive of other segments of those routes. This count misses people who board elsewhere and get off on 125th, but conversely assigns people who board on 125th and get off elsewhere to this street and not the other segment. But with this caveat in mind, this points to about 11,000 weekday riders per route-km, ahead of New York’s busiest bus per unit length (the M86, with about 7,000), and not far behind the subway average (15,000). This is despite the fact that, in my experience going between Columbia and the Metro-North station at Park Avenue, those buses are not faster than walking.
- East-west transit in Uptown Manhattan consists of Pokey-winning crosstown buses; the 125th Street buses are as slow on 125th. An underrated feature of Second Avenue Subway Phase 1 is that it will soon enable a two-seat subway ride from the Upper East Side to the Upper West Side, West Harlem, and Washington Heights. However, this option will require connecting at Times Square, and is useful mainly for people in the southern areas of the Upper East Side connecting to the 1/2/3 rather than to the A/B/C/D. A two-seat ride based on going up Second Avenue to 125th Street and thence connecting to the 2/3, A/B/C/D, or 1 would enable more connections, many without any backtracking. This could have a potential cascading effect on all Uptown east-west buses, and not just those using 125th Street.
Of course, a Second Avenue Subway extension on 125th Street cannot be exactly like the pink line in the diagram above, because a key feature of it is that the circumferential part is not in fact near the outer end of the city. It’s barely 5 km north of the northern edge of Midtown, not even halfway from Midtown to the northern ends of most preexisting north-south subway lines. This is how it can have such high residential and commercial density and strong transit demand. Much farther north, Fordham Road is a very strong bus corridor, with about 4,500 weekday riders per route-km on the Bx12, but this is at much higher speed than in Manhattan, about 13 km/h rather than 5 km/h. An extension of the A east toward the Bronx under Fordham would underperform, because Fordham just doesn’t have that much demand; but 125th does.
The result of this discrepancy is that in a small city, one whose subway system is only about as large as in the diagram, it’s unlikely that such circumferential extensions would work. A radial line built all the way out is going to have as its terminus either a relatively low-density area or an anchor point, such as a commercial center or big housing project, neither of which lends itself to a strong continuous circumferential corridor. A radial line built part of the way to the edge of the city could potentially find a Tehran Avenue or a 125th Street, but if the system is small, with many key outlying neighborhoods still unserved, then it is usually best to keep extending lines outward.
The factors that conspire to make a 125th Street subway extension work are in place precisely because New York already has a large, mature subway network, in which Second Avenue Subway is a relief line. Certainly the projected demand on Second Avenue is very high, but the East Side is already served by a north-south subway 500-600 meters to the west of this line; it’s being built because this subway is overcrowded, not because the East Side has no access. This means that there’s more leeway with choosing what to do with the line once it reaches Harlem – after all, the Bronx subways are not overcrowded, and do not need relief.
Whereas mixed lines like the above-depicted yellow line are always bad transit, mixed lines like the pink line, in which the circumferential part is farther out than the radial part, are potentially an option for large cities that already have many rapid transit lines. They are especially useful for providing connections between closely parallel radial lines when other crosstown transit options are slow, and should be considered as extensions for relief lines, provided the radial lines farther out do not need relief as well.
Note on definitions: for the purposes of this post, a tramway is a light rail line that runs predominantly on streets, interfacing with cross-traffic even if it has signal priority. It can be a legacy streetcar in mixed traffic, or a newer light rail line running on dedicated lanes. It is distinguished from lines that have substantial grade-separated segments, including subway-surface lines, where these segments are in city center while the suburban segments are in tramway mode, and tram-trains and most North American light rail lines, where these segments are in the suburbs while the city-center segments are in tramway mode.
Intermediate in capacity between the surface bus and the rapid transit train is the tram. Running on the street, perhaps with signal priority but without the absolute priority that mainline trains have at grade crossings, trams are still surface transit, but feature better ride quality, generally higher capacity in terms of vehicles per hour, and generally bigger vehicles. A number of cities have been building such transit in recent years, most notably Paris, which has been making the rounds on the Transit Center for having almost a million daily riders on its system. The Transit Center gives various recommendations based on Paris’s success, but those recommendations – frequency, fare integration, good transfers – say very little about where a city should be building tramway lines. In this post, I am going to sketch features of good corridors for tramways.
1. Tramways are surface transit
There are various features that make for good surface transit routes. Jarrett Walker, who has extensive experience in bus network redesigns, outlined some of them in a network design document he collaborated on for TransLink. These include high density along the route, relatively balanced demand in both directions, and the potential for a strong everywhere-to-everywhere grid. Additional important features of strong bus routes: a single street with few twists, since turns slow down surface vehicles a lot, and swerving to reach major destinations is often cumbersome; and a wide street, since in practice few cities will give transit dedicated lanes if there’s not enough room for cars as well. These rules do not apply to subways, which can zigzag between different streets or carve a new alignment. However, they do apply to tramways.
2. The strongest bus corridors are in most need of investment
In a city where the buses that can support high frequency already are frequent, the highest potential for extra ridership is on routes that are already strong. Imagine a bus that averages 15 km/h: replacing it with a 20 km/h tram that provides a smoother and more reliable ride has benefits in rough proportion to existing bus ridership. Since both buses and trams are surface transit and follow the same rules, it’s unlikely that there are routes that would make good trams but poor buses. This is in stark contrast with subways, where a potentially strong corridor may not have a continuous surface right-of-way for high bus ridership. On the surface, this corridor could not succeed as either a bus or a tram. This is a specification of the BMT’s all four concept (bus, trolleybus, tramway, subway), in which the four modes work in complement, and the busiest routes in each category are upgraded to the next based on a tradeoff between construction costs and operating costs.
3. In a city with subways, the tramways should be placed on routes that would make poor subway corridors
It goes without saying that tramways should not duplicate subways. But more than that, if a bus route is so strong that it’s a potential subway extension, it should not be turned into a tram. At first pass, this may look like the best bus routes to be turned into trams are not quite the busiest, but the next tier of busier buses. However, this has to do not just with ridership, but also layout relative to the subway system. The subway is almost invariably radial, so strong buses that make easy radials or branches of radials would be strong subway routes, while circumferential buses would not. A radial bus may also turn out to be a poor subway route, if it happens to point in a direction where a subway wouldn’t be a good fit, but this is less likely.
4. A connected network is beneficial, but not required
Ideally, all light rail routes – not just tramways, but also subway-surface routes and tram-trains if they exist – should form a connected graph, with track connections, to enable maximum flexibility in yard placement and reduce the required spare ratio. However, this is not a requirement. Large, busy systems in particular may economically have a yard serving just 1-2 lines, in which case the value of connectedness decreases. In conjunction with point #3, cities with large radial subway networks may have disconnected circumferential tramways, including Paris.
5. When there’s a choice between several tramways and a subway, tramways work better when there’s no dominant route
The construction cost of a subway, in developed countries that are not the US, is $100-300 million per km, with outliers outside the range in both directions. The construction cost of a tramway in the same countries is $15-50 million per km, again, with outliers. The choice of whether to build one subway or six tramways depends on how busy the strongest route is relative to the next five routes. If two strong bus routes are closely parallel, then both should be reckoned together for subway ridership estimates (and to some extent also for tram ridership), since people walk longer to better service, in this case a fast subway rather than a slow bus. Another consideration, more about construction costs than ridership, is whether there exists a good right-of-way for the subway, perhaps an abandoned or low-ridership commuter line that can be converted, that would make it possible to limit tunneling.
Boston has few long, wide roads; Massachusetts Avenue is one of very few exceptions. Downtown Boston and the surrounding neighborhoods have very narrow streets, which is why the Boston bus network is sparse downtown – the buses feed outlying subway stations, or stop at the edge of the central business district at Haymarket, and almost never enter the downtown core. Because of the Green Line, some strong radial routes, such as the Washington Street half of the Silver Line, and the 23 bus on Blue Hill Avenue, are naturally good extensions of the subway-surface network; they’d make good light rail, but not all-surface tramways.
In strongly gridded cities, including Chicago, Vancouver, Toronto, and Los Angeles, it doesn’t make too much sense to build individual tramways; instead, the entire frequent bus grid could be so upgraded, or possibly just the lines that are perpendicular to the rapid transit system in Chicago and Toronto. Unfortunately, this runs into high construction costs, which leads to questions of priorities: build an expansive light rail network, or extend a few subway lines.
I believe Los Angeles and Vancouver are doing right in choosing to prioritize subways on their strongest corridors. Vancouver in particular is an extreme example of point #5 pointing toward a subway, with 80,000 weekday riders on Broadway and another 40,000 on the routes interlining on 4th Avenue 500 meters away (not all on 4th, as two of the four 4th Avenue routes have substantial tails elsewhere), compared with 110,000 on the next five routes combined; Vancouver also seems to have an unusually low subway-to-tram cost ratio, only about 2.7 rather than 6. Los Angeles has a less extreme version of point #5, but Wilshire and very close-by routes dominate east-west traffic, and can also easily feed into the existing subway.
In Chicago, the circumferential nature of the top bus routes – north-south west of the Loop, east-west north and south of it – makes an L extension infeasible, so from point #3, any solution has to involve surface transit. The current plan is dedicated bus lanes. In Toronto this decision is more difficult, and acrid debates between a mostly-surface option and an all-underground option led to the latter choice, influenced by Rob Ford’s unwillingness to take road lanes from cars; right now Toronto is building one subway line (update: it’s mixed subway-surface), under Eglinton, and one tramway, on Finch West.
In New York, Bill de Blasio proposed a tram route near the Brooklyn and Queens waterfront earlier this year; see background articles here and here. This route is ill-suited for the technology proposed, or for any significant investment. The buses along the waterfront are all quite weak. In both Brooklyn and Queens, the busiest buses are in the interior, some going perpendicular to the subway, such as the Q44 on Main Street and B35 on Church, and some serving radial routes that have long been planned to be subway extensions, namely the B46 on Utica and B44 on Nostrand. Select Bus Service investments have targeted these routes, and now the Q44, B44, and most recently the B46 all have SBS features.
Another weakness of the proposed route is that it subtly combines circumferential and radial service; see here for why this is poor practice. While the line is for the most part straight, the north-south segment in Queens is essentially radial, going from Astoria to Long Island City, parallel to the N/Q subways, before switching to circumferential between Long Island City and Downtown Brooklyn. South of Downtown Brooklyn it becomes radial again, connecting to Red Hook and Sunset Park. Riders in Astoria going south are mostly interested in continuing toward Manhattan and not toward Brooklyn; riders in Sunset Park and Red Hook going north would first of all follow different routes (Sunset Park already has the N and R subways and has no use for a detour through Red Hook), and second of all be more interested in going to Manhattan than to Williamsburg and points north.
While de Blasio’s proposal is bad transit, there are routes in New York that could make strong tramways. None of them is on the city’s redevelopment agenda, based on the principle that US cities almost never invest in low- and lower-middle-income neighborhoods except when they are about to gentrify, but the bus ridership there is solid, even though the buses crawl.
The busiest routes in New York are the M15 on 1st and 2nd Avenues in Manhattan, the B46, and the Bx12 on Fordham Road; each has been the single busiest in one of the last few years, but usually the M15 is first. The first two are strong subway routes: the first phase of Second Avenue Subway will soon open, and the rest will be built when the city can find multiple billions per kilometer for them; Utica is also a strong route, and de Blasio proposed it last year before abandoning the idea. But Fordham satisfies point #4 perfectly: it is circumferential, and can only realistically extend the A train, already the system’s longest route, with a mismatch in potential ridership between the core radial segment and what a Fordham subway would get. The Bx12 was the first route to be turned into SBS, and is either the strongest potential tramway in the city, or one of the few strongest.
Going further down the list, we should eliminate the strong Brooklyn routes, except the B41 on Flatbush. The B44 is also a potential subway extension, and the three busiest circumferentials – the B6, B35, and B82 – all parallel the Triboro right-of-way, which by point #5 is a superior project to building multiple light rail lines. The busiest bus in Queens, the Q58, has a long segment between Queens and Brooklyn, about half its total length, that would be obviated by Triboro as well.
The B41 could be a tramway going between City Hall and Kings Plaza, using two dedicated lanes of the Brooklyn Bridge. In that case, the line would effectively act as subway-surface, or more accurately elevated-surface: a surface segment in Brooklyn, a grade-separated segment between Manhattan and Brooklyn. Subway-surface lines should branch, as all current examples do (e.g. Boston Green Line, Muni Metro, Frankfurt U-Bahn), because the subway component has much higher capacity than the surface components. This suggests one or two additional routes in Brooklyn, which do not have strong buses, but may turn into strong tramways because of the fast connection across the river to Manhattan. The first is toward Red Hook, which is not served by the subway and cut off from the rest of the city by the Gowanus Expressway. Unfortunately, there is no really strong corridor for it – the streets are not very wide, and the best for intermediate ridership in Cobble Hill and Carroll Gardens require additional twists to get into the core of Red Hook. Court Street might be the best compromise, but is annoyingly a block away from the F/G trains, almost but not quite meeting for a transfer. The second possible route is along Flushing Avenue toward the Navy Yard; it’s not a strong bus by itself, but the possibility of direct service to Manhattan, if a Flatbush tramway preexists, may justify it.
In the Bronx and Queens, a more conventional network is called for. The Bronx in particular has several strong bus lines forming a good grid, in addition to the Bx12. The east-west routes cannot possibly be made into subway extensions, while the north-south ones have nowhere to go to in Manhattan except possibly a Second Avenue Subway extension, and even that is doubtful (if there’s money to extend Second Avenue Subway north, it should instead go west under 125th Street). A light rail grid could consist of the Bx12 as outlined above, a Tremont line acting as a compromise between the Bx36 and Bx40/42 feeding into Manhattan on 181st Street, a 161st/163rd Street route going into Manhattan on 155th Street replacing the Bx6, a Southern/Manhattan 145th Street route along the Bx19, a Third Avenue route along the Bx15, and a Grand Concourse route along the Bx1/2. Grand Concourse has a subway, but the Bx1/2 nonetheless currently ranks 5th in the city in weekday ridership, and the street is so wide that it’s a good candidate for light rail. Update: a Webster Avenue route along the Bx41 is also feasible, I just forgot it when writing this post.
In Queens, there’s less room for a grid. Main Street is a strong route, connecting to Tremont in the Bronx via the Whitestone Bridge, as the Q44 SBS already does today. A second route between Flushing and Jamaica, on Kissena and Parsons, could also get a tramway. These two routes are uniquely bad subways, since they connect two busy subway lines, both of which could be extended past their termini outward. The main route on Kissena, the Q25, and another route slightly farther east, the Q65, rank 3rd and 2nd among the MTA buses, separate from the New York City Transit buses, with about 20,000 weekday riders each; they also continue north to College Point, which could get a tramway, or perhaps even a subway extension of the 7, depending on whether there are plans to redevelop the Flushing Airport site.
If there is not enough ridership on both Kissena and Main, then only Main should be turned into light rail. More potential corridors include the Q46 on Union Turnpike and the Q10 on Lefferts going to JFK (the busiest MTA bus). Unfortunately, Queens buses tend to be on the long side, e.g. the Q27, the borough’s number 3 bus after the Q58 and Q46, is 15 km long; in the Bronx the longest, Tremont, would be 13 km, cobbled out of busier buses, and most are about 10 km. The Q44 is even longer, at 20 km; light rail is only justified there because of extra local ridership coming from the Q20 local and from the fact that the Queens-Bronx segment over the bridge would be rapid transit. Even then, the tramway may only be justified from Flushing south.
I don’t want to make recommendations for priorities and an exact fantasy map in New York, as those depend on construction costs and the available budget. Fordham and Main Street are most likely the two strongest initial choices. Judging by the cost estimate for de Blasio’s waterfront proposal, tramways in New York are about $60-70 million per km, which in an inverse of the situation in Vancouver leads to an unusually high subway : tram cost ratio, 25 if we take the Manhattan subway extensions (Second Avenue and the 7 extension) as our examples, probably less but not much less if we look at a hypothetical Utica subway. This should bias New York rail extensions toward surface transit.
De Blasio proposed $1.5 billion for about 25 km of tramway on the waterfront. The waterfront idea is bad, and money can and should go elsewhere; 25 km is slightly longer than the combined length of the Bx12 and the B46 from Flushing south. Those two together could be the start of a program to bring surface rail back to New York, using the same routing reasoning that made Paris’s program so successful. Using ridership on the existing buses and adjusting upward for rail bias, initial ridership on those two lines combined should be higher than 100,000 per day, and with more lines and a bigger network, fast multiplication of overall traffic can be expected.
As the Regional Plan Association continues to work on its Fourth Regional Plan, expected to be published next year, it’s releasing various components of the upcoming agenda. One, an update from the Third Regional Plan from 1996, is a line variously called Triboro or Crossboro. In the third plan, Triboro RX was meant to be a circumferential subway line, taking over existing abandoned and low-traffic freight rail rights-of-way in Brooklyn, Queens, and the South Bronx, terminating at Yankee Stadium via a short tunnel. It was never seriously proposed by any political actor, but was briefly mentioned positively by then-MTA chair Lee Sander in 2008, and negatively mentioned by Christine Quinn, who called for a bus line along a parallel alignment in her mayoral campaign in 2013. In 2014, Penn Design proposed a variant it calls Crossboro, which differs from the original Triboro proposal in two ways: first, the stop spacing is much wider, and second, instead of the short tunnel to Yankee Stadium, it continues northeast along the Northeast Corridor, making four stops in the Bronx as in the proposed Metro-North Penn Station Access plan. Crossboro is an inferior proposal, and unfortunately, the fourth plan’s Triboro proposal downgrades it from the original alignment to Crossboro.
As I explained a year and a half ago, specifically in the context of Crossboro, it is poor planning to run train service that begins as a radial and then becomes as a circumferential instead of continuing into the center. The route of Crossboro, and now also the Triboro plan, involves going from the North Bronx to the south in the direction of Manhattan, but then turning southeast toward Queens and Brooklyn, rather than continuing to Manhattan. Briefly, in a system with radial and circumferential routes (as opposed to a grid), circumferential service is the most effective when it connects to secondary centers, and has easy transfers to every radial. If a line runs as a radial and then switches to circumferential, its ability to connect to other radials is compromised, making it a weaker circumferential; nor could it ever be even a half-decent radial without service to the CBD. Lines with such service pattern, such as Line 3 in Shanghai and the G train in New York until 2001, tend to underperform.
However, the stop spacing deserves to be treated separately. Under both Crossboro and the RPA’s new version of Triboro, there are too few stops for the line to be useful as an urban rail service. I’m going to ignore the connection between Queens and the Bronx, which as a major water crossing can be expected to have a long nonstop segment, and talk first about the Bronx, and then about Queens and Brooklyn.
In the Bronx, there are four stops in 10 km, starting counting from where the bridge toward Queens begins to rise. This may be reasonable for a commuter rail service with local service extending well past city limits (to New Rochelle or even Stamford), but when it terminates within the city, it’s too far for people to be able to walk to it. The proposed stops also miss the Bronx’s most important bus route, the Bx12 on Fordham Road, which in 2015 became the city’s busiest single bus route. A stop on the Pelham Parkway, the continuation of Fordham in the East Bronx, would be a massive travel time improvement over trying to reroute the Bx12 to meet a train station near Coop City, the proposed northern terminus of both Crossboro and the new Triboro. Conversely, it would delay few other passengers, by very little, since there would only be one further stop north. The result of the proposed stopping pattern is then that most people living near the line would not be able to either walk to it or take a frequent bus.
In Queens and Brooklyn, starting from Astoria and going south, the route is 26 km long, and the new Triboro makes 17 stops. The average interstation, 1.5 km, is noticeably above the international subway average, and is especially high for New York, whose stop spacing is near the low end globally. The original version had 29 stops over the same distance, and one more stop between Astoria and the bridge. Unlike in the Bronx, in Brooklyn all streets hosting major radial routes get subway stops. However, long stretches of the route get no stops. The stop spacing is not uniform – from Northern Boulevard to Grand Avenue there’s a stretch with 4 stops in 2.8 km (counting both ends), but from Astoria-Ditmars to Northern Boulevard there’s a 2.5 km nonstop service, skipping Astoria Boulevard and Steinway, passing through a medium-density neighborhood south of the Grand Central Parkway with mediocre subway access. A stop at Astoria Boulevard and Steinway is obligatory, and probably also one between Astoria and Northern, around 49th Street. To the south of Grand Avenue, the proposal calls for a 2.1 km nonstop segment to the M terminus at Metropolitan Avenue, skipping Middle Village, which is cut off from Grand by the Long Island Expressway and from the M by cemeteries. An additional stop in the middle of this segment, at Eliot Avenue, is required.
In Brooklyn, the route runs express next to the L train, splitting the difference between serving Broadway Junction (with a connection to the A/C) and Atlantic Avenue (with a connection to the LIRR): the RPA’s diagram depicts a station at Atlantic Avenue but calls it Broadway Junction. Farther south, it makes a few stops on an arc going southwest toward southern Brooklyn; the stops are all defensible, and the stop spacing could potentially work, but there are still potential missing locations, and some nonstop segments in the 1.7 km area. For example, it goes nonstop between Utica and Nostrand Avenues, a distance of 1.7 km, with a good location for an interpolating station right in the middle, at Albany Avenue. From Nostrand west, it stops at a transfer to every subway line, except the R. In that segment, one more stop could be added, between the F and the D/N; the reason is that the gap between these two lines is 1.8 km, and moreover the right-of-way slices diagonally through the street grid, so that travel time from the middle to either stop is longer along the street network. However, overall, this is not why I dislike the route. Finally, at the western end, the route is especially egregious. The right-of-way is parallel to the N train, but then awkwardly misses 59th Street, where the N veers north and starts going toward Manhattan. The original proposal had a stop several blocks away from 59th, with a long transfer to the R (and N); this one drops it, so there is no R transfer in Brooklyn – trains express from the D/N transfer at New Utrecht to the terminus at Brooklyn Army Terminal, where there is very little development. There are practically no through-riders who would be inconvenienced by adding the extra two N stops in between. In contrast, due to the low frequency of the N (it comes every 10 minutes off-peak), making passengers originating in those stations who wish to ride Triboro transfer would add considerably to their travel time.
A route like Triboro has an inherent problem in deciding what stop spacing to use, because as a circumferential, it is intended to be used on a large variety of origin-destination pairs. For passengers who intend to connect between two outer radial legs more quickly than they could if they transferred in Manhattan, the wider stop spacing, emphasizing subway connections, is better. However, the mixed radial-circumferential nature of the new Triboro makes this a losing proposition: there’s no connection to any subway line in the Bronx except the 6. Moreover, in Brooklyn, there’s no connection in Brooklyn to the R, and if there’s a connection to the A/C, it involves walking several hundred meters from what on the L is a separate subway stop.
In contrast, for passengers whose origins are along the line, narrower stop spacing works better, because they’re unlikely to cluster around the connection points with the radial subway lines. (The line has no compelling destinations, except maybe Jackson Heights and Brooklyn College; in the Bronx, the two most important destinations, the Hub and Yankee Stadium, are respectively close to and on the old Triboro route, but far from the new one.) The aforementioned Astoria/Steinway, Eliot, and Albany, as well as the skipped stations along the L and N routes, all have reasonable numbers of people within walking distance, who have either poor subway access (the first three) or only radial access (the L and N stations).
What’s more, if trains make more stops, the increase in travel time for passengers connecting between two legs is not large compared with the reduced station access time for passengers originating at an intermediate station. The reason is that passengers who connect between two legs are not traveling all the way. The fastest way to get from the West Bronx to southern Brooklyn is to take the D train all the way, or take the 4 to the D; from the 6 train’s shed, the fastest way is to take the 6 and transfer to the N/Q at Canal or the B/D at Broadway/Lafayette. No circumferential service can change that. The benefit of circumferential service is for people who travel short segments: between the Bronx and Queens, or between the 7 or the Queens Boulevard trains and the lines in Brooklyn that aren’t the F. Given high circumferential bus ridership in Brooklyn – two circumferential routes, the B6 and B35, rank 2nd and 4th borough-wide and 4th and 7th citywide, despite averaging maybe 9 km/h – connections between two Brooklyn legs are also likely. For those passengers, making a few more local stops would add very little to travel time. The subway has a total stop penalty of about 45 seconds per station. Of the ten extra stops I list as required – Astoria/Steinway, Eliot, Albany, 59th, four along the L, and two along the N – three (the two on the N and 59th) are basically end stations, and few passengers have any reason to travel over more than five of the rest. In contrast, adding these ten stops would improve the quality of transfers to the R and A/C and provide crucial service to intermediate neighborhoods, especially Middle Village.
Finally, let me make a remark about comparative costs. The original Triboro plan required a short tunnel, between Melrose Metro-North station and Yankee Stadium; the new one does not. However, a single kilometer of new tunnel in the context of a 34 km line is not a major cost driver. The new proposal is actually likely to be more expensive. It is longer because of the segment in the Bronx along the Northeast Corridor, about 40 km in total, and 10 km would be alongside an active rail line. There are plans for increased mainline passenger rail service on the line: Penn Station Access, plus any improvements that may be made to intercity rail. Far from offering opportunities to share costs, such traffic means that any such plan would require four tracks on the entire line and flying junctions to separate trains going to Penn Station from trains going to Brooklyn. Fare collection would be awkward, too – most passengers would transfer to the subway, so subway faregates would be required, but commuter rail has no need for faregates, so sharing stations with Penn Station Access would require some kludge that wouldn’t work well for any mode. Tunneling is expensive in New York, but so is at-grade construction; a kilometer of tunnel in the Bronx is unlikely to cost more than configuring an active rail mainline for a combination of suburban and high-frequency urban service.
The RPA proposes the London Overground as a model, treating the new Triboro as a commuter line offering subway service levels. Everywhere else I’d support this idea. But here, it fails. First, as I explained in a previous post, the routing is an awkward mix of radial and circumferential. But second, the stop spacing only works in the context of a long suburban line feeding city center, and not an urban circumferential line. In the context of an urban line, more stops are needed, to let people walk from more neighborhoods to the train, or take a connecting bus. For the most part, the original Triboro plan, designed around interstations of about 900 meters not counting the water crossing, would work well. Crossboro, and its near-clone the new Triboro, is inferior to it in every respect, and the RPA should jettison it from the Fourth Regional Plan in favor of the old proposal.
I recently visited New York. I stayed in Kew Gardens Hills, a neighborhood located between Jamaica and Flushing, just close enough to the subway that it’s plausible to walk but just far enough that this walk is uncomfortable and I preferred to take a bus. The bus route, Main Street, is one of Queens’ busiest (see data here and here). I’ve been calling for investment in it for years, going back to a fantasy spite map I drew so long ago I don’t remember what year it was, and continuing more recently in my post on where New York should and shouldn’t build light rail. Last year, the route did get Select Bus Service, and I took it a few times. The result is not good.
Main Street maintains two bus corridors: the local Q20, and the Select Bus Service Q44. Almost every SBS route is an overlay of a local route and a rapid route; on the local route passengers must board from the front and pay within view of the driver, and on the rapid route passengers must validate a ticket at ticketing machines beforehand and can then board the bus from any stop, with the fare enforced via random checks for ticket receipts. This leads to the following problems, some preventable, some inherent to this setup:
- Passengers who can take either the local or the SBS route need to decide in advance whether to validate their tickets at the machines or not, based on whether the next bus is SBS. The resulting last-minute validation delays boarding. After the mayhem caused by the introduction of SBS to the M15, on First and Second Avenues, bus drivers on local routes began to accept the receipts spitted out by the SBS ticketing machines. However, this practice is either inconsistent or not widely-known among occasional bus riders, such as the people I was staying with, who own cars.
- The combination of local and limited buses on a medium-frequency route such as Main Street makes it impossible to maintain even headways. Even within each route (Q20 or Q44) I repeatedly saw bunching, but the different speeds of the Q20 and Q44 make bunching between a local and an express inevitable at some point on the route. Off-peak weekday frequency is 10 minutes on the Q20 and 8 on the Q44, which isn’t good enough to justify this split, especially given the bunching within each route; some stations will always be scheduled to have 8-minute service gaps, and in practice could see 15-minute gaps because of the bunching. See more on this problem of locals and rapids on infrequent routes on Human Transit.
- The expense of the ticketing machines ($75,000 per stop for a pair of modified MetroCard vending machines and a machine that takes coins) limits how widely they can be installed. Everywhere else where proof-of-payment is used, holders of valid transfers and season passes can just board the train or bus and show their pass to an inspector. This would be especially useful in New York, because the biggest crunch at SBS stops occurs when many passengers arrive at the stop at once, which in turn is the most common where passengers transfer from the subway. The slow process of validating a ticket leads to queues at busy times, and adding more machines is difficult because of their cost.
- Stop spacing is never what it should be. Most developed countries have converged on a standard of about 400-500 meters between successive bus stops. North America instead has converged on 200 meters, leading to slow buses that stop too often; see an old Human Transit post on the subject here. The stop spacing on the segment of the Q44 I was using was two stops in 1.7 km, leading to long walks between stops.
- On the schedule, the Q44 makes 15 stops in 9.2 km between its origin in Jamaica and Flushing, and takes 42 minutes in the midday off-peak. This is an average speed of 13.1 km/h. In contrast, Vancouver’s limited-stop buses, which average about a stop per kilometer on Broadway and 4th Avenue, average 20 km/h and 30 km/h respectively; the 4th Avenue buses do not have off-board fare collection, but there’s less traffic than on Broadway, and the stoplights give priority to through-traffic, both private and public, over crossing traffic.
The basic problem with New York’s approach to Select Bus Service is that all North American bus rapid transit ultimately descends from Jaime Lerner’s sales pitch of BRT as a cheap subway on tires, at grade. Lerner implemented BRT in Curitiba successfully, in the context of low wages: construction costs appear to only weakly depend on wealth (see e.g. my posts here, here, here, here, and here), but bus driver costs rise with average income, making replacing fifteen bus drivers with one subway driver a crucial money saver in rich cities and an unaffordable luxury in poor ones. North American BRT imitates Latin American BRT’s role as a cheap subway substitute, and ignores the superior usage of bus services in Europe, with which American transit planners do not dialog; there’s no systematic dialog with Latin American planners either, but Lerner has aggressively pitched his ideas to receptive audiences, whereas no comparable figure has pitched European-style reforms to the US.
In cities that think of BRT as a subway substitute, the BRT network will tend to be small, consisting of a few lines only serving the most important corridors, and bundle various features of improved transit together (off-board fare collection, larger vehicles, bus lanes, signal priority). After all, a line can’t be partly a subway and partly a bus. In Bogota, whose BRT system has eclipsed Curitiba and is the world’s largest, the BRT lines run different vehicles from the local lines: local buses have doors opening on the right to the curb, BRT buses have doors opening on the left to a street median bus station, some hybrids have buses with doors on both sides (see photos on Spanish Wikipedia). ITDP, which promotes Latin American-style BRT around the world, has a BRT scoring guideline that awards points to systems that brand their BRT lines separately from the rest of the bus network, as New York does with SBS.
In the European thinking, there’s already an improved quality urban transit service: the subway, or occasionally the tram. The bus is a bus. The biggest difference is that subway networks are smaller than bus networks. Paris and London, both with vast urban rail networks, have a number of subway lines measured in the teens, plus a handful of through-running commuter services; they have hundreds of bus routes. Instead of branding a few buses as special, they invest in the entire bus network, leading to systemwide proof-of-payment in many cities. Bus lanes and signal priority are installed based on demand on an individual segment basis. New York installs bus lanes without regard to local versus SBS status, but retains the special SBS brand, distinguished by off-board fare collection, and only installs it on a per-route basis rather than systemwide.
The other issue, unique to New York, is the ticket receipts. Everywhere else that I know of, bus stops do not have large ticket machines as New York does. Vancouver, which otherwise suffers from the same problem of having just a few special routes (called B-Lines), has no ticket machines at B-Line stops at all: people who have valid transfers or monthly passes can board at their leisure from any door, while people who don’t pay at the front as on local buses. SBS in contrast does not give passengers the option of paying at the front. In New York, people justify the current system by complaining that the MetroCard is outdated and will be replaced by a smart card any decade now; in reality, systems based on paper tickets (including Vancouver, but also the entire German-speaking world) manage to have proof-of-payment inspections without smartcards. Small devices that can read the MetroCard magnetic stripe are ubiquitous at subway stops, where people can swipe to see how much money they have left.
The right path for New York is to announce that every bus route will have off-board fare collection, regardless of stop spacing. It should also engage in stop consolidation to reduce the interstation to about 400-500 meters, but this is a separate issue from fare collection. Similarly, the question of bus lanes should be entirely divorced from fare collection. There should be no ticketing machines at bus stops of the kind currently used. At most, stops should have validators, similar to the MetroCard readers at subway turnstiles but without the fare barrier. Validators are not expensive: smartcard readers in Singapore are consumer items, available to people for recharging their cards at home via their credit cards for about $40, a far cry from the $75,000 cost in New York today. People with valid transfers or unlimited cards should be able to board without any action, and people without should be able to pay on the bus.
Finally, the split between local and rapid routes should be restricted to the busiest routes, with the highest frequency in the off-peak. Conceivably it should be avoided entirely, in favor of stop consolidation, in order to increase effective frequency and reduce bunching. The city’s single busiest route, the M15, has 7-minute SBS and 8-minute local service in the midday off-peak, and given how slow the local is, it’s enough to tip the scales in favor of walking the entire way if I just miss the bus.
It is a truth universally acknowledged that cities spend far more per rider on airport connectors than on other kinds of public transit. On this blog, see many posts from previous years on the subject. My assumption, and that of such other transit advocates as Charles Komanoff, was always that it came from an elite versus people distinction: members of the global elite fly far more than anyone else, and when they visit other cities, they’re unlikely to take public transit, preferring taxis for most intermediate-length trips and walking for trips around the small downtown area around their hotels.
In this post, I would like to propose an alternative theory. Commuters who use public transit typically use their regular route on the order of 500 times a year. If they also take public transit for non-work trips around the city, the number goes even higher, perhaps 700. In contrast, people who fly only fly a handful of times per year. Frequent business travelers may fly a few tens of times per year, still an order of magnitude less than the number of trips a typical commuter takes on transit.
What this means is that 2 billion annual trips on the New York-area rail network may not involve that many more unique users than 100 million annual trips between the region’s three airports. Someone who flies a few times per year and is probably middle class but not rich might still think that transportation to the airport is too inconvenient, and demand better. In the US, nearly half the population flies in any given year, about 20% fly at least three roundtrips, and 10% fly at least five. Usually, discussions of elite versus regular people do not define the elite as the top half; even the top 10% is rare, in these times of rhetoric about the top 1% and 0.1%. When Larry Summers called for infrastructure investment into airport transit, he said it would improve social equity because what he considered the elite had private jets.
But what’s actually happening is not necessarily about the top 0.1% or 1% or even 5% directing government spending their way. It may be so; certainly politicians travel far more than the average person, and so do very rich donors. But broad segments of the middle class fly regularly. The average income of regular fliers is presumably considerably higher than that of people who do not fly, but not to the same extent as the picture drawn by political populists.
None of this makes airport transit a great idea. Of course some projects are good, but the basic picture is still one in which per rider spending on airport connectors is persistently higher than on other projects, by a large factor. In New York, the JFK AirTrain cost about $2 billion in today’s money and carries 6.4 million riders a year, which would correspond to 21,000 weekday riders if it had the same annual-to-weekday passenger ratio as regular transit, 300 (it has a much higher ratio, since air travel does not dip on weekends the way commuter travel does). This is around $100,000 per rider, which contrasts with $20,000 for Second Avenue Subway Phase 1 if ridership projections hold. Earlier this year, the de Blasio administration proposed a developed-oriented waterfront light rail, projected to cost $1.7 billion and get 16 million riders a year, which corresponds to about $32,000 per daily rider; a subsequent estimate pegs it at $2.5 billion, or $47,000 per rider, still half as high as how much the AirTrain cost.
However, what I propose is that the high cost of airport connectors is not because the elite spends money on itself. Rather, it’s because many ordinary middle-class people fly a few times a year and wish for better airport transit, without thinking very hard about the costs and benefits. An airport connector appeals to a very wide section of the population, and may be very cheap if we divide the cost not by the number of daily users but by the number of unique annual users. Hence, it’s easier for politicians to support it, in a way they wouldn’t support an excessively costly subway line connecting a few residential neighborhoods to the city.
It’s a political failure, but not one that can be resolved by more democratic means. The conventional analysis that the root cause is excessive attention to elite concerns implies that if spending were decided in more democratic ways, it would be directed toward other causes. But if the hypothesis I’m putting forth is right, then democracy would not really resolve this, since the number of people who would benefit from an airport connector, if only shallowly, is large. A rigorous regime of cost-benefit analyses, including publicized estimates of cost per rider and the opportunity cost, would be required.
Last summer, I brought up a metric of railroad labor efficiency: annual revenue hours per train driver. Higher numbers mean that train drivers spend a larger proportion of their work schedule driving a revenue train rather than deadheading, driving a non-revenue train, or waiting for their next assignment. As an example, I am told on social media that the LIRR schedules generous crew turnaround times, because the trains aren’t reliably punctual, and by union rules, train drivers get overtime if because their train is late they miss the next shift. Of note, all countries in this post have roughly the same average working hours (and the US has by a small margin the highest), except for France, which means that significant differences in revenue hours per driver are about efficiency rather than overall working hours.
I want to clarify that even when union work rules reduce productivity, low productivity does not equal laziness. Low-frequency lines require longer turnaround times, unless they’re extremely punctual. Peakier lines require more use of split shifts, which require giving workers more time to commute in and out.
The database is smaller than in my posts about construction costs, because it is much harder to find information about how many train operators a subway system or commuter railroad employs than to find information about construction costs. It is often also nontrivial to find information about revenue hours, but those can be estimated from schedules given enough grunt work.
In Helsinki, there is a single subway trunk splitting into two branches, each running one train every 10 minutes all day, every day: see schedules here and here. This works out to 65,000 train-hours a year. There are 75 train drivers according to a 2010 factsheet. 65,000/75 = 867 hours per driver. This is the highest number on this list, and of note, this is on a system without any supplemental peak service, allowing relatively painless scheduling.
In Toronto, there were 80,846,000 revenue car-km on the subway in 2014
(an additional line, the Scarborough Rapid Transit, is driverless). Nearly all subway trains in Toronto have six cars; the Sheppard Line runs four-car trains, but is about 10% of the total route-length and runs lower frequency than the other lines. So this is around 13.5 million revenue train-km. According to both Toronto’s schedule of first and last trains per station and this chart of travel times, average train speed is around 32 km/h between the two main lines, and a bit higher on Sheppard, giving about 420,000 annual service hours. In 2009, there were 393,000 hours. Toronto runs two-person train operation, with an operator (driver) and a guard (conductor); this article from 2014 claims 612 operators and guards, this article from 2009 claims 500 operators alone. 420,000/500 = 840, and, using statistics from 2009, we get 393,000/500 = 786; if the article from 2014 misrepresents things and there are 612 drivers in total, then 420,000/612 = 686. If I had to pick a headline figure, I’d use 786 hours per driver, using the 2009 numbers. Update: the Scarborough RT is not driverless, even though the system could be run driverless; from the same data sources as for the subway, it had 23,000 operating hours in 2014, which adds a few percent to the operating hours per driver statistic.
In London, unlike in North America, the statistics are reported in train-km and not car-km. There are 76.2 million train-km a year, and average train speed is 33 km/h, according to a TfL factsheet; see also PDF-p. 7 of the 2013-4 annual report. In 2012, the last year for which there is actual rather than predicted data, there were 3,193 train drivers, and according to the annual report there were 76 million train-km. 76,000,000/33 = 2,300,000 revenue-hours; 2,300,000/3,193 = 721 hours per driver.
In Tokyo, there used to be publicly available information about the number of employees in each category, at least on Toei, the smaller and less efficient of the city’s two subway systems. As of about 2011, Toei had 700 hours per driver: from Hyperdia‘s schedules, I computed about 390,000 revenue train-hours per year, and as I recall there were 560 drivers, excluding conductors (half of Toei’s lines have conductors, half don’t).
In New York, we can get revenue car-hour statistics from the National Transit Database, which is current as of 2013; the subway is on PDF-p. 13, Metro-North is on PDF-p. 15, and the LIRR is on PDF-p. 18. We can also get payroll numbers from SeeThroughNY. The subway gets 19,000,000 revenue hours per year; most trains have ten cars, but a substantial minority have eight, and a smaller minority have eleven, so figure 2,000,000 train-hours. There were 3,221 train operators on revenue vehicles in 2013, and another 373 at yards. This is 556 hours per driver if the comparable international figure is all drivers, or 621 if it is just revenue vehicle drivers. The LIRR gets 2,100,000 annual revenue car-hours, and usually runs trains of 8 to 12 cars; figure around 210,000. There were 467 engineers on the LIRR in 2013; this is 450 hours per driver. Metro-North gets 1,950,000 annual revenue car-hours, and usually runs 8-car trains; figure about 240,000. It had 413 locomotive engineers in 2013; this is 591 hours per driver.
In Paris, the RER A has 523 train drivers (“conducteurs”). The linked article attacks the short working hours, on average just 2:50 per workday. The timetable is complex, but after adding the travel time for each train, I arrived at a figure of 230,000 train-hours a year. 230,000/523 = 440 hours per driver. There’s a fudge factor, in that the article is from 2009 whereas the timetable is current, but the RER A is at capacity, so it’s unlikely there have been large changes. Note also that in France, workers get six weeks of paid vacation a year, and a full-time workweek is 35 hours rather than 40; adjusting for national working hours makes this equivalent to 534 hours in the US, about the same as the New York subway.
Stockholm is currently expanding its transit system, with about 19 kilometers of subway extension, and another 6 kilometers of a commuter rail tunnel taking regional traffic off the at-capacity mainline. The subway extension, excluding rolling stock acquisition, costs about $2.1 billion, and the commuter rail extension $1.8 billion.
The US is currently building five subways: Second Avenue Subway Phase 1 (2.8 km, $4.6 billion), East Side Access (2.2 km, $10 billion), the first phase of the Wilshire subway (6.3 km, $2.8 billion), the Regional Connector (3.1 km, $1.4 billion), U-Link (5 km, $1.8 billion). Two more projects are partially underground: the Crenshaw/LAX Line, a total of 13.7 km of which 4.7 are underground, at a total cost of $2.1 billion, and the Warm Springs BART extension, a total of 8.6 km of which 1.6 are underground, at a total cost of $900 million. (Update 2/1: the Central Subway is $1.6 billion for 2.8 km. Thanks to Joel for pointing out that I forgot about it.)
The first observation is that Sweden has just
700 meters 3.5 km of subway under construction less than the US under construction, despite a vast gap in not only population but also current transit usage. Stockholm may have twice the per capita rail ridership of New York, but it’s still a small city, the size of Indianapolis, Baltimore, Portland, or Charlotte; 450 million annual rail trips is impressive for a city of its size, but the US combined has more than 3 billion. This relates to differences in costs: the amount of money Sweden is putting into heavy rail infrastructure is $3.9 billion, vs. $23.6 billion $25.2 billion among the seven eight US projects, which approaches the ratio of national subway and commuter rail ridership levels.
The second observation is that the US spending is not really proportional to current rail ridership. Two thirds of the spending is in New York, as is two thirds of US rail ridership, but nearly everything else is in Los Angeles, which takes in a majority of current subway construction route-length. Los Angeles is a progressive city and wants better public transit, but the same is true in many of the six major US transit cities – New York, Washington, San Francisco, Chicago, Boston, and Philadelphia. And yet, of those six, only New York and San Francisco are building urban subways (BART’s one mile of tunnel is in a suburb, under a park).
The difference is that Los Angeles builds subways at $400-450 million per km in the city core (less in future phases of the Wilshire subway), whereas in most of the US, lines are either more expensive or more peripheral. Boston, the Bay Area, and Washington are expanding their rapid transit networks, but largely above-ground or in a trench, and only outside the core. Boston’s Green Line Extension is in a trench, but has had major budget overruns and is currently on the high side for a full subway ($3 billion for 6.9 km), and the MBTA is even putting canceling the project on the table due to the cost. Washington’s Silver Line Phase 2 is 18.5 km and $2.7 billion, in a highway median through the Northern Virginia suburbs. BART’s Warm Springs extension is about $100 million per km, which is not outrageously high, but the next extension of the line south, to Berryessa, is $2.3 billion for 16 km, all above ground.
Let us now stay on the North American West Coast, but go north, to Vancouver. Vancouver’s construction costs are reasonable: the cost projections for the Broadway subway (C$2.7 billion ex-vehicles, PDF-p. 95) are acceptable relative to route-length (12.4 km, PDF-p. 62) and very good relative to projected ridership (320,000 per weekday, PDF-p. 168). Judging by the costs of the Evergreen and Canada Lines, and the ridership evolution of the Canada Line, these projections seem realistic. And yet, in a May 2015 referendum about funding half the line as well as many other transit projects, 62% of the region’s voters, including a bare majority in Vancouver proper, voted no.
The referendum’s result was not a shock. In the few months before the vote, the polls predicted a large, growing no vote. Already in February, the Tyee was already comparing Vancouver negatively with Stockholm, and noting that TransLink’s regional governance structure was unusual, saying the referendum was designed to fail. This is not 100% accurate: in 2014, polls were giving the yes side a majority. The deterioration began around the end of 2014 or beginning of 2015: from 52-39 in December to 46-42 in January, to 27-61 in March. The top reason cited by no voters was that they didn’t trust TransLink to spend the money well.
This cannot be divorced from Vancouver’s Compass Card debacle: plans to replace paper tickets and SkyTrain’s proof-of-payment system with a regionwide smartcard, called Compass, and faregates on SkyTrain, were delayed and run over budget. The faregates aren’t even saving money, since TransLink has to pay an operating fee to vendor Cubic that’s higher than the estimated savings from reduced fare evasion. The height of the scandal was in 2014, but it exploded in early 2015, when TransLink replaced its manager amidst growing criticism. The referendum would probably have been a success a year earlier; it was scheduled in what turned out to be a bad period for TransLink.
The importance of the Vancouver example is that construction costs are not everything. Transit agencies need to get a lot of things right, and in some cases, the effects are quite random. (Los Angeles, too, had a difficult rollout of a Cubic-run faregate system.) The three key principles here are, then:
1. Absolute costs matter. They may not directly affect people’s perceptions of whether construction is too expensive. But when legislators have to find money for a new public transit project, they have some intuitive idea of its benefits, give or take a factor of perhaps 2. Gateway is being funded, even though with the latest cost overrun (to $23.9 billion) the benefit-cost ratio in my estimation is about 1/3, but this involved extensive lobbying by Amtrak, lying both to Congress and to itself that it is a necessary component of high-speed rail. Ordinary subways do not have the luxury of benefiting from agency imperialism the way the Gateway project did; if they’re too expensive, they’re at risk of cancellation.
2. Averaged across cities and a number of years of construction, cities and countries with lower construction costs will build more public transit. We see this in the US vs. Sweden. Of course, there are periods of more construction, such as now, and periods of less, such as around 2000, but this affects both countries right now.
3. Variations from the average are often about other issues of competence – in Vancouver’s case, the failure of the faregates and the delayed Compass rollout. Political causes are less important: Vancouver’s business community opposed the transit referendum and organized against it, but it’s telling that it did so and succeeded, whereas business communities in cities with more popular transit authorities support additional construction.
In a post from 2011, Yonah Freemark argued that California HSR’s projected cost’s upper end was just 0.18% of the projected GDP of California over a 20-year construction period. The implication: the cost of high-speed rail (and public transit in general) is small relative to the ability of the economy to pay. This must be paired with the sobering observation that the benefits of public transit are similarly small, or at most of the same order of magnitude.
New York’s survived decades without Second Avenue Subway. It’s a good project to have, provided the costs are commensurate with the benefits, but without cost containment, phase 2 is probably too expensive, and phases 3 and 4 almost certainly. What’s more, the people funding such projects – the politicians, the voters, even the community organizations – consider them nice-to-haves. The US has no formal mechanism of estimating benefit-cost ratios, and a lot of local political dysfunction, and this can distort the funding, to the point that Gateway is being funded even though at this cost it shouldn’t. But, first, even a factor of 3 distortion is unusual, and second, on average, these distortions cancel out. Democrats and Republicans shouldn’t plan on controlling either Congress or the White House more than about half the time, in the long run, and transit activists shouldn’t plan on political dysfunction persistently working in their favor.
The only route forward is to improve the benefit-cost ratio. On the benefit side, this means aggressive upzoning around subway stations, probably the biggest lacuna in Los Angeles’s transit construction program. But in New York, and even in the next five transit cities in the US, this is not the main problem: population density on many corridors is sufficient by the standards of such European transit cities as Stockholm, Berlin, London, and Munich, none of which is extraordinarily dense like Paris.
No: the main problem in most big US cities is costs, and almost only costs. Operating costs, to some extent, but mainly capital construction costs. Congress and the affected states apparently have enough political will to build a 5-km tunnel for $20 billion going on $24 billion; if this system could be built for $15 billion, they’d jump at the opportunity to take credit. The US already has the will to spend reasonable amounts of money on public transit. The difference is that its
$24 billion $25 billion of spending on subways buys 26 km 28.5 km of subway and 16 km of a mix of light rail and el, where it could be buying 120 km 125 km of subway. Work out where you’d build the extra 94 km 96.5 km and ask yourself if ignoring costs is such a good idea for transit activists.
In Seattle, there is an ongoing controversy over a plan to redesign the bus network along the principles proposed by Jarrett Walker: fewer one-seat rides to the CBD, more frequent lines designed around transfers to Link, the city’s light rail system. For some background about the plans, see Capitol Hill Seattle, Seattle Transit Blog, and the transit agency on a restructure specific to an upcoming Link extension to the university (U-Link), and Seattle Transit Blog on general restructure, called RapidRide+. The U-Link restructure was controversial in the affected neighborhood, with many opposing changes to their particular bus route.
Since the core of the plan, as with many restructure plans in North America, is to get people to transfer between frequent core routes more and take infrequent one-seat rides less, this has led to discussion about the concept of transfers in general, and specifically the transfer penalty. I bring this up because of a new post by Jason Shindler on Seattle Transit Blog, which misunderstands this concept. I would like to both correct the mistake and propose why transfers lead to so much controversy.
The transfer penalty is an empirical observation that passengers prefer trips with fewer transfers, even when the travel time is the same. Usually, the transfer penalty is expressed in terms of time: how much longer the one-seat ride has to be for passengers to be indifferent between the longer one-seat trip and the shorter trip with transfers. For some literature review on the subject, see Reinhard Clever’s thesis and a study by the Institute for Transportation Studies for the California Department of Transportation.
Briefly, when passengers take a transit trip with a transfer, making the transfer takes some time, which consists of walking between platforms or stops, and waiting for the connecting service. Passengers weight this time more heavily than they do in-vehicle travel time. According to New York’s MTA’s ridership model, passengers weight transfer time 1.75 times as much as they do in-vehicle time. In other words, per the MTA, passengers are on average indifferent between a one-seat ride that takes 37 minutes, and a two-seat ride that takes 34 minutes of which 4 are spent transferring. Observe that by the MTA’s model, timed cross-platform transfers are zero-penalty. Other models disagree – for example, the MBTA finds an 11-minute penalty on top of a 2.25 factor for transfer time.
The transfer penalty can be reduced with better scheduling. Timed transfers reduce the waiting penalty, first because there is less waiting on average, and second because the (short) waiting time is predictable. When transfers cannot be timed, I believe countdown clocks reduce the waiting penalty. Walking between platforms or bus stops can be made more pleasant, and bus stops can be moved closer to train station entrances.
However, regardless of what the transit agency does, the transfer penalty is an average. Even for the same origin and destination, different people may perceive transfers differently. Any of the following situations can result in a higher transfer penalty:
- Heavy luggage. This also leads to bias against staircases, and often against transit in general and for cars and taxis. The waiting penalty does not grow, but there may be a significant penalty even for cross-platform transfers.
- Travel in large groups, especially with children. As an example, in comments here and on Itinerant Urbanist, Shlomo notes that ultra-Orthodox Jews, who travel with their large families, prefer one-seat bus rides over much faster and more frequent train rides. Families of 3-5 are also much likelier to drive in a family car than to take an intercity train or bus.
- Disability, including old age. This has similar effect to heavy luggage.
- Lack of familiarity with the system. This is common for tourists but also for people who are used to taking a particular bus route who are facing significant route restructuring. This can also create a large bias in favor of trams or trolleybuses, since their routes are marked with overhead wires and (for trams) rails, whereas bus routes are not so obvious.
- Reading, or getting other work done in transit. For longer intercity trips, sleeping is in this category, too. This tends to bias passengers against mid-trip transfers especially, more so than against start-of-trip and end-of-trip transfers.
- Seat availability. Passengers who get on a bus or train when it still has seats available may prefer to keep their seat even if it means a longer trip, and this shows up as a transfer penalty. This does not usually affect start-of-trip transfers (buses and trains probably still have seats), but affects mid- and end-of-trip transfers.
In contrast, people who are not in any of the above situations often have very low transfer penalties. In New York, among regular users of the subway who do not expect to get a seat, zero-penalty transferring appears to be the norm, especially when it’s cross-platform between local and express trains on the same line.
Usually, people in groups 3 and 4 are the major political forces against bus service restructuring plans. They’re also less willing to walk longer distances to better service, which makes them oppose other reforms, including straightening bus routes and increasing the average interstations in order to make bus routes run faster. This is also true of people in groups 1 and 2, but usually those are not inherent to the passenger: most disabled people are always disabled, but most passengers with luggage usually travel without luggage. The one exception is airport travel, where luggage is the norm, and there we indeed see more advocacy for one-seat rides to the CBD.
The key observation here is that even a route change that is a net benefit to most people on a particular origin-destination pair is sometimes a net liability to some riders on that pair. While it’s a commonplace that reforms have winners and losers, for the most part people think of it in terms of different travel patterns. Replacing a CBD-focused system with a grid leads to some losers among CBD-bound riders and winners among riders who travel crosstown; boosting off-peak frequency creates winners among off-peak travelers; straightening one kink in a bus route leads to losers among people served by that kink and winners among people riding through. The different transfer penalties are a different matter: even on the same origin-destination pair, among people traveling at the same time, there are winners and losers.
Solutions to this issue are bound to be political. The transit agency can estimate the net benefit of a restructure, and sell it on those grounds, but it’s not completely a win-win; thus some political process of conflict resolution is required.
In this particular case, the community process is reasonable. The main flaw of the community process is that the people who come to meetings are not representative of the body of riders and potential riders, and are especially likely to be NIMBYs. For example, on Vancouver’s West Side, the community meetings for the Broadway subway were dominated by NIMBYs who didn’t want outsiders (especially students) to have an easier commute to UBC, and not by people who could use the subway, often traveling through the West Side without living or working in it.
But the conflict when it comes to transfers is between groups of people who live in the same area. Moreover, there is no clear bias in either direction. Older people, who are usually more averse to change, are especially likely to show up to meetings; but so are transit activists, who are more informed about the system and thus more willing to transfer. People with intense familiarity with their home bus line are balanced out by people with familiarity with the system writ large. There is also no opposition of a widely shared but small benefit to most against a narrow loss to the few: instead, such reforms produce a large array of changes, ranging from major gains to major losses. Finally, frequent bus grids do not generate much transit-oriented development, unlike rail, which produces NIMBY contingents who are against transit investment on the grounds that it would lead to upzoning and new development (as in the above example from Vancouver).
The result is that here, political control can lead to positive outcomes, as the transit agency is required to consider the effect of change on many subsets of riders. Frequent grids really do generate losers, who deserve to be heard. In this case, it appears that they are outnumbered by winners, but the winners have as much of a political voice as the losers; there is no large gap between good transit and what the community thinks good transit is.
In New York, the MTA has consistent guidelines for how frequently to run each subway route, based on crowding levels. The standards are based on crowding levels at the point of maximum crowding on each numbered or lettered route. Each line is designed to have the same maximum crowding, with different systemwide levels for peak and off-peak crowding. While this approach is fair, and on the surface reasonable, it is a poor fit for New York’s highly branched system, and in my view contributes to some of the common failings of the subway.
Today, the off-peak guidelines call for matching frequency to demand, so that at the most crowded, the average train on each route has 25% more passengers than seats. Before the 2010 service cuts, the guidelines had the average train occupied to exact seating capacity. At the peak, the peak crowding guidelines are denser: 110 passengers on cars on the numbered lines, 145 on shorter (60’/18 m) cars on the lettered lines, 175 on longer (75’/23 m) cars on the lettered lines. There’s a minimum frequency of a train every 10 minutes during the day, and a maximum frequency at the peak depending on track capacity. When the MTA says certain lines, such as the 4/5/6, are operating above capacity, what it means is that at maximum track capacity, trains are still more crowded than the guideline.
In reality, guideline loads are frequently exceeded. Before the 2010 service cuts, many off-peak trains still had standees, often many standees. Today, some off-peak trains are considerably fuller than 25% above seated capacity. In this post, I’d like to give an explanation, and tie this into a common hazard of riding the subway in New York: trains sitting in the tunnels, as the conductor plays the announcement, “we are delayed because of train traffic ahead of us.”
The key takeaway from the system is that frequency at each time of day is calculated separately for each numbered or lettered route. Even when routes spend extensive distance interlined, as the 2/3 and 4/5 do, their frequencies are calculated separately. As of December 2014, we have the following headways, in minutes:
|Line||AM peak||Noon off-peak||PM peak|
Consider now the shared segments between the various lines. The 4 comes every 4.5 minutes in the morning peak, and the 5 every 5 minutes. There is no way to maintain even spacing on both lines with these headways: they share tracks for an extensive portion of their trip. Instead, the dispatchers move trains around to make sure that headways are as even as possible on both the shared trunk segments and the branches, but something has to give. In 45 minutes, there are ten 4s and nine 5s. Usually, on trunk lines with two branches, trains alternate, but here, it’s not possible to have a perfect alternation in which each 4 is followed by a 5 and each 5 is followed by a 4. There is bound to be a succession of two 4s: the second 4 is going to be less crowded than the guideline, and the following 5 is going to be more crowded.
It gets worse when we consider the extensive reverse-branching, especially on the lettered lines. For example, on its northbound journey, the Q initially does not share tracks with any line; then it shares tracks with the B, into Downtown Brooklyn; then it crosses into Manhattan sharing tracks with the N; then it again shares tracks with no other route, running express in Manhattan while the N runs local; then it shares tracks with the N and R into Queens; and then finally it shares tracks with the N in Queens. It is difficult to impossible to plan a schedule that ensures smooth operations like this, even off-peak, especially when the frequency is so variable.
Concretely, consider what happens when the Q enters Manhattan behind an N. Adequate separation between trains is usually 2 minutes – occasionally less, but the schedule is not robust to even slight changes then. To be able to go to Queens ahead of the N, the Q has to gain 4 minutes running express in Manhattan while the N runs local. Unfortunately, the Q’s express jaunt only skips 4 stations in Manhattan, and usually the off-peak stop penalty is only about 45 seconds, so the Q only gains 3 minutes on the N. Thus, the N has to be delayed at Herald Square for a minute, possibly delaying an R behind it, or the Q has to be delayed 3 minutes to stay behind the N.
In practice, it’s possible to schedule around this problem when schedules are robust. Off-peak, the N, Q, and R all come every 10 minutes, which makes it possible to schedule the northbound Q to always enter Manhattan ahead of the N rather than right behind it. Off-peak, the services they share tracks with – the B, D, and M – all come every 10 minutes as well. The extensive reverse branching still makes the schedule less robust than it can be, but it is at least possible to schedule non-conflicting moves. (That said, the M shares tracks with the much more frequent F.) At the peak, things are much harder: while the N, Q, and R have very similar headways, the D is considerably more frequent, and the B and M considerably less frequent.
I believe that this system is one of the factors contributing to uneven frequency in New York, with all of the problems it entails: crowding levels in excess of guidelines, trains held in the tunnel, unpredictable wait times at stations. Although the principle underlying the crowding guidelines is sound, and I would recommend it in cities without much subway branching, in New York it fails to maintain predictable crowding levels, and introduces unnecessary problems elsewhere.
Instead of planning schedules around consistent maximum crowding, the MTA should consider planning schedules around predictable alternation of services on shared trunk lines. This means that, as far as practical, all lettered lines except the J/Z and the L should have the same frequency, and in addition the 2/3/4/5 should also have the same frequency. The 7 and L, which do not share their track or route with anything else, would maintain the present system. The J/Z, which have limited track sharing with other lines (only the M), could do so as well. The 1 and 6 do not share tracks with other lines, but run local alongside the express 2/3 and 4/5. Potentially, they could run at exactly twice the frequency of the 2/3/4/5, with scheduled timed local/express transfers; however, while this may work for the 6, it would give the 1 too much service, as there is much more demand for express than local service on the line.
To deal with demand mismatches, for example between the E/F and the other lettered lines, there are several approaches, each with its own positives and negatives:
– When the mismatch in demand is not large, the frequencies could be made the same, without too much trouble. The N/Q/R could all run the same frequency. More controversially, so could the 2/3/4/5: there would be more peak crowding on the East Side than on the West Side, but, to be honest, at the peak the 4 and 5 are beyond capacity anyway, so they already are more crowded.
– Some services could run at exactly twice the frequency of other services. This leads to uneven headways on the trunks, but maintains even headways on branches. For example, the A’s peak frequency is very close to exactly twice that of the C, so as they share tracks through Lower Manhattan and Downtown Brooklyn, they could alternate A-C-A-empty slot.
– Services that share tracks extensively could have drastic changes in frequency to each route, preserving trunk frequency. This should be investigated for the E/F on Queens Boulevard: current off-peak frequency is 8 trains per hour each, so cutting the E to 6 and beefing the F to 12 is a possibility.
– Service patterns could be changed, starting from the assumption that every lettered service runs every 10 minutes off-peak and (say) 6-7 minutes at the peak. If some corridors are underserved with just two services with such frequency, then those corridors could be beefed with a third route: for example, the Queens Boulevard express tracks could be supplanted with a service that runs the F route in Jamaica but then enters Manhattan via 53rd Street, like the E, and then continues either via 8th Avenue like the E or 6th Avenue like the M. Already, some peak E trains originate at Jamaica-179th like the F, rather than the usual terminus of Jamaica Center, which is limited to a capacity of 12 trains per hour.
– The service patterns could be drastically redrawn to remove reverse branching. I worked this out with Threestationsquare in comments on this post, leading to a more elegant local/express pattern but eliminating or complicating several important transfers. In particular, the Broadway Line’s N/Q/R trains could be made independent of the Sixth Avenue trains in both Queens and Brooklyn, allowing their frequencies to be tailored to demand without holding trains in tunnels to make frequencies even.
For the lettered lines, I have some affinity for the fourth solution, which at least in principle is based on a service plan from start to finish, rather than on first drawing a map and then figuring out frequency. But it has two glaring drawbacks: it involves more branching than is practiced today, since busy lines would get three services rather than two, making the schedule less robust to delays; and it is so intertwined with crowding levels that every major service change is likely to lead to complete overhaul of the subway map, as entire routes are added and removed based on demand. The second drawback has a silver lining; the first one does not.
I emphasize that this is more a problem of reverse branching than of conventional branching. The peak crowding on all lines in New York, with the exception of the non-branched 7 and 1, occurs in the Manhattan core. Thus, if routes with different colors never shared tracks, it would not be hard to designate a frequency for each trunk route at each time of day, without leading to large mismatches between service and demand. In contrast, reverse branching imposes schedule dependencies between many routes, to the point that all lettered routes except the L have to have the same frequency, up to integer multiples, to avoid conflicts between trains.
The highly branched service pattern in New York leads to a situation in which there is no perfect solution to train scheduling. But the MTA’s current approach is the wrong one, certainly on the details but probably also in its core. It comes from a good place, but it does not work for the system New York has, and the planners should at least consider alternatives, and discuss them publicly. If the right way turns out to add or remove routes in a way that makes it easier to schedule trains, then this should involve extensive public discussion of proposed service maps and plans, with costs and benefits to each community openly acknowledged. It is not good transit to maintain the current scheduling system just because it’s how things have always worked.