Category: New York
What’s the Infrastructure’s Highest Value?
A piece of land and infrastructure may have multiple uses. Land might be needed for urban development or for a highway. A two-track structure might be needed for freight or passenger service. A right-of-way might be needed for multiple kinds of rail, or a road, or a power line easement, or a park. In all cases, the correct policy choice is to allocate the land to the use that has the highest social value, and this use depends on the situation at hand. It should not be allocated to whatever one fancies.
Concretely, let us consider the following cases:
1. The High Line. Occasionally, railfans grumble about the linear park, and say it should’ve had passenger rail service instead; read the comments on Ben Kabak’s post on linear parks, or New York City subway forums. But in reality, the High Line is very useful as a park in a busy neighborhood that doesn’t have other parks. In contrast, it’s nearly worthless as a transit line: it’s parallel to a north-south subway that’s operating well below capacity, it would be nightmarishly difficult to connect to any existing line, and the only east-west service it could possibly be useful for is connecting to 14th Street, not the most important job destination in the city.
2. The Northeast Corridor in Rhode Island, south of Providence. The expansion of MBTA commuter rail southward into sprawling exurbs is a major failure of regional transportation policy. Providence is not all that congested by the standards of the larger Northeastern cities; auto-oriented commuter rail toward it is doomed to fail, and near-downtown parking is cheap and plentiful. (The commute market from Warwick and Wickford Junction to Boston is trivial.) In contrast, the line is perfect for intercity service, since it has relatively gentle curves outside city limits, and is straight south of East Greenwich. The South County project not only costs $200,000 per weekday rider, but also makes poor use of high-speed track. Since the line is more important as high-speed rail than as a commuter line, Amtrak should be more aggressive about demanding that commuter projects create their own capacity.
3. The Northeast Corridor in Maryland, north of Baltimore. For the same reasons as the MBTA extension’s eventual failure, MARC underperforms north of Baltimore. Although the line has extensive three- and four-track segments, the bridges are two-tracked, and high-speed rail should again be given priority, including canceling commuter rail if necessary. Ironically, because of more extensive four-tracking, the need for bypasses around Wilmington and perhaps North East, and the at-grade track layout, Perryville is quite easy to connect to Philadelphia by commuter rail without interfering with intercity rail.
4. Caltrain to San Jose, the MBTA to Providence, MARC to Baltimore. In contrast with the situation in points #2-3, those three lines are all useful commuter lines; they are all similar in that they connect two distinct cities that share suburbs, with a rump extension that exists purely for show (into Gilroy, Perryville, and soon to be Wickford Junction). Any and all high-speed rail use of these corridors should permit a reasonable frequency of commuter trains, with timed overtakes when possible and full four-tracking otherwise. On Caltrain, in particular, interference with commuter rail is one reason why the chosen Pacheco Pass alignment is inferior to the Altamont alignment.
5. The Lower Montauk Line. Despite perennial railfan desires (and an empty Bloomberg campaign promise, since scrubbed from his campaign website) to restore passenger service, there’s not much point in regional rail that stub-ends in Long Island City. To give an idea how much demand there is, the LIRR currently runs 5 trains per day per direction into Long Island City. Thus, the line is more useful for freight trains than for passenger trains. This will change if, and only if, there is a way to connect the line to Manhattan through the existing LIRR tunnels, or perhaps new tunnels, but then the cost is going to be orders of magnitude higher than just restoring service.
6. Urban freeways, e.g. the BQE. American freeways were built at a time when, even more so than today, land was allocated based on political power rather than any sort of social consensus or market pricing concept. While Japanese cities have to make do with 4-lane freeways due to high land costs and strong property rights protections, American cities demolished entire neighborhoods to make room for freeways with wide exclusion zones around them. The land occupied by some would be more useful for additional neighborhood housing growth than it is for a freeway. For example, the BQE hogs prime real estate in Williamsburg, right next to the under-capacity Marcy Avenue subway station, and to a lesser extent in the rest of Brooklyn and Queens, and this land could be used for high-density development instead.
Regional Rail to Lower Manhattan
Staten Islanders’ desire for a subway connection got me thinking again about my previous proposal for a tunnel from Staten Island to Manhattan, possibly with a cross-platform connection to Brooklyn and New Jersey. From all points of view, it is desirable to build a regional rail hub near Fulton Street, and connect it to nearby commuter lines, creating a second pole for an RER- or S-Bahn-like system in New York, in addition to a Midtown pole centered around Penn Station. My intention in this post is to discuss tradeoffs in choosing how to build it.
As the source of the ARC and ESA cost overruns is the station caverns in Manhattan, the Fulton Street station should be minimalistic: as close as possible to the surface (closer to 20 meters underground than to 55), without a full-length mezzanine, and with only four tracks, one to each of Midtown, Brooklyn, New Jersey, and Staten Island. It should under no circumstances look like the ESA extravaganza. This economizing means it’s difficult to build this as a terminal: ideally the station box would be built and then tunnels would be built to all four destinations, making two two-track lines.
The length of this station should be 300 meters, to accommodate 12-car trains, but if it’s too hard to build within the available footprint, then a shortening to 10- or even 8-car trains is feasible. Regional trains in both Paris and Tokyo are usually only 200 meters long. In addition, unlike its Parisian inspiration, Chatelet-Les Halles, Fulton Street need not have very wide platforms. When I took the RER A and changed trains at Chatelet, at 8:40 in the morning, the platform was about as crowded as that of a normal subway station, and needed much less than its full width of 17 meters. Indeed, the Chuo Line, with far higher peak load than anywhere in the West, terminates on a single 10-meter-wide island platform. A single-level four-track station with a cross-platform transfer should be about 30-35 meters wide; since it is too wide for most Lower Manhattan Streets, another option is a bilevel station with two tracks per level, with useful cross-platform transfers, and about 15-18 meters wall to wall per level.
The best time to have built this project was right after 9/11. Because of the connection to World Trade Center, it could have been funded out of 9/11 recovery funds, which instead went to the Calatrava PATH terminal. In addition, the rebuilding of WTC and the PATH terminal could have been done in tandem with the new train station, making its placement far easier. Alas, this did not happen, and all available space east of the WTC site is gone.
The difficult part in building this is the train station, not the access tunnels. Access tunnels can be built very deep using tunnel-boring machines and can even go directly underneath existing subway tunnels. For example, Paris Métro Line 14, whose construction cost was low relative to its depth and Paris’s underground complexity, goes parallel to and under Line 7 for a short segment, and a few kilometers of the RER D were constructed alongside the preexisting RER A tunnel. While I’m not aware of similar examples outside Paris, this shows that it is doable. In contrast, I don’t know of new stations built right underneath preexisting stations in parallel except for some high-cost US projects like the BART Market Street Tunnel Sixth Avenue Subway (thanks to Adirondacker for the correction). Stations-under-stations in oblique configurations exist in Paris, but the biggest station, namely Chatelet-Les Halles, avoids this.
The upshot is that many streets in Lower Manhattan are suitable for new tunnels, and it’s even possible to have access tunnel go deep under building foundations. However, since nearly all suitable north-south streets already host subways, a new station is more difficult. The option for a station under an existing subway station exists, but would be expensive. Let us then scout alternative locations.
Although it’s desirable to have cross-platform transfers, this configuration is more difficult than a cross configuration, in which the Brooklyn-New Jersey line goes east-west in Manhattan. This is because under a north-south configuration it may be difficult to have the Brooklyn-New Jersey tracks dive and turn west fast enough to connect to the desired New Jersey end. An east-west configuration also permits narrower single-level station caverns.
Finally, we should consider the fact that peak employment in Lower Manhattan is around Wall Street, judging by where skyscrapers are located, whereas the main station to connect to is at Fulton Street. In both cases, the key location is well east of the WTC site. Thus a Cortlandt Street location is suboptimal, and a West Street location, where there’s enough space for everything, is too far away. We will repeatedly look at the location relative to existing subway stations in Lower Manhattan: close is good, intersection is not so good.
With the above in mind, here are the options:
East-West Lines
Liberty Street
Advantages: wide enough for everything for a long stretch, from Cortlandt to beyond William. A possible 18*300 box exists from Nassau to Cortlandt, requiring demolition of at most a few low-rise buildings west of Church Street; another box with a slight curve exists from Church to William. There’s a 200-meter stretch that’s 25-meter wide from building edge to building edge. Zucotti Park permits a main entrance with enough space for pedestrians that commuters wouldn’t saturate the neighborhood’s narrow streets. Liberty is close to quite close to the center of Lower Manhattan. Brushes off against the existing Cortlandt Station on the R, but stays away from the other subway stations.
Disadvantages: far from Fulton Street (200 meters); closer to the Wall Street subway station than to the Fulton Street station on the 2/3 and J/Z. Also far from one of the easiest if not the most convenient locations for a north-south line. (But see at the end of the post for update.)
Vesey Street
Advantages: one block from Fulton. There’s an easy location for a north-south line (even a four-track one) next to City Hall, right north of Vesey. St. Paul’s Churchyard can act as the equivalent of Zucotti Park for the Liberty option. Intersects just one subway line, the E. There’s a very easy 200-meter box beginning at Broadway and continuing east.
Disadvantages: far from where most Lower Manhattan workers want to go to. A 300-meter box requires going under Vesey north of WTC, where building foundations may be a problem, or through narrow right-of-way under Ann. Continuing west requires threading the narrows between 1 WTC and 7 WTC, and continuing east requiring threading the Ann Street narrows.
John/Dey Streets
Advantages: one block from Fulton. Almost as close to where most people work as Liberty. Close to the Fulton Street stationhouse, which may be developed into a major retail destination because of the subway station.
Disadvantages: even a 200*15 box would require a few low-rise demolitions. To the east it could thread the John Street narrows, but to the west it would dip under WTC foundations and the memorial. A 300-meter box is impossible without going under skyscraper foundations (fortunately, nothing supertall). Crosses right under the J/Z and 4/5, though the active constraint for depth is probably the WTC foundations to the west.
North-South Lines
City Hall Park
Advantages: enormous space for everything, including a 35*300 box that misses all building foundations, all subway stations, and possibly all subway tunnels. Can bend to the south under Broadway and go under a mid-rise building to the north. A lot of space for pedestrian circulation both in the park and on Broadway.
Disadvantages: closer to the City Hall subway stations than to Fulton – in other words, located about half a subway stop farther away from the CBD than Fulton, which is already at the margin of the main cluster of skyscrapers. If it were picked, then there would probably be a need for a South Ferry train station serving the southern end of Lower Manhattan, which is about a kilometer from the southern end of this location – and South Ferry is so close to the water the station would have to be deep-level.
Broadway
Advantages: close to everything. The street offers about 21 meters of width until well south of Zucotti Park, which is more than enough for a box, and the only stretch narrower than about 24 is at Fulton and John, where the buildings are lower-rise.
Disadvantages: right under and parallel to the 4/5. If this is a four-track option, then this means putting the station at levels -2 and -3. It’s no big deal by the standards of Chatelet-Les Halles or especially Auber, but the RER A was expensive for its time. And even the Chatelet train box was built between two Métro stations (Chatelet and Les Halles, hence the name) rather than under a station.
Church Street or Nassau Street, taking over a subway line
Advantages: could leverage some existing structures, no interference from the subway for rather obvious reasons; under both options the J/Z would terminate at Chambers, where there are existing tracks for it, and under the Church Street option the R would be rerouted along a short new tunnel (cheap by the standards of what we’re talking about here) and thence the Nassau Street tracks. Nassau is literally in the center of the Fulton Street complex.
Disadvantages: beyond the immense subway disruption this would cause, the tracks are old and have insufficient loading gauge. In addition, Nassau, the less disruptive option and the one that is closer to the peak employment center, is a narrow street and even its two subway tracks are on separate levels (see track map). Existing track geometry may impose unreasonable curves, causing squeal.
Greenwich Street
Advantages: serves WTC. Already has a grand terminal because of PATH, reducing the likelihood that politicians will spend billions on starchitecture. I believe that when the street is remapped after WTC construction is complete, it will be 18 meters wide from building to building, permitting an ample train box, even a four-track bilevel one. There’s an easy way to continue both north and south, allowing shallow construction, right underneath the 1 and PATH.
Disadvantages: too far west of where most Lower Manhattan employment is. The PATH terminal may impose unreasonable constraints. Taking over the 1 is a possibility, but presents the same difficulties as taking over the R or J/Z, and would also require an additional South Ferry station, at great depth. The proximity to WTC means the national security agencies may shit bricks about such good transit designs as shallow platforms, maximally free pedestrian circulation, and an open station. Of course the TSA and associated paranoid agencies should be (and is) fought whenever it is required, but ideally agencies should avoid situations that invite a fight they may lose.
Pearl/Water Street
Advantages: Pearl is wide enough for everything north of Fulton, and Water is wide enough south to Pine but with a 22-meter narrows between Fulton and John. Free of obstructions, as the only intersecting subway line, the A/C, is already deep. Can continue south fairly easily as well as north, curving west under the Brooklyn Bridge ramps.
Disadvantages: far east of the existing train station – 300 meters just to the 2/3 at Williams. On a similar note, east of most development; the block east of Pearl and north of Beekman is a parking lot. Conflicts with Second Avenue Subway Phase 4, but this is a small problem as the box could be built with provisions for a two-track subway underneath at little additional cost.
Gold Street
Advantages: close to both the subway station and most Lower Manhattan development. Crosses the A/C line but no station. Can continue north very easily because of the Brooklyn Bridge ramps.
Disadvantages: some room to the north of Fulton, away from the development, but very little south of Fulton; even 250*15 would brush up against the southern end of the street, which is flanked by skyscrapers. In a similar vein, continuing south requires bending west under William or maybe east under Pearl, and both require tunneling under buildings with three-figure height.
Dutch Street, or between Broadway and Nassau
Advantages: both options offer the ability to thread through some gaps in the skyscrapers, going under lower-rise buildings or lower-rise sections of the skyscrapers and limiting the amount of demolition required. Literally at the same site as the subway station. Quite close to most commercial buildings.
Disadvantages: even a 200*15 box would probably require deep-level construction to limit demolitions. Has some leeway to the south and north (assuming shallow construction) but much less than options using continuous streets. In other words, very expensive.
Update: another option is to route the Staten Island-Manhattan tunnel through Brooklyn, in which case it comes into Manhattan from the east, allowing a four-track east-west option. Both Vesey and Liberty present the option of the line to Grand Central branching north under West, then diagonally once deep enough that it can freely go under private property. Vesey presents the additional option of going north under Greenwich, which conflicts with nothing. Conversely, Liberty has the advantage of being south of the 9/11 memorial rather than south of skyscrapers, allowing the turn to West to have much wider curve radius (about 200 meters) without going under any building or the footprint of the Twin Towers.
A Transit City is a Centralized City
In New York, a large fraction of employment clusters in a rectangle bounded roughly by 59th Street, 2nd Avenue, 42nd Street, and 9th Avenue. Although it’s a commonplace that New York employment is centralized around Manhattan, in reality most of Manhattan is residential, and employment is concentrated in a few square kilometers in the heart of Midtown. This is where the subway lines converge from all directions – elsewhere there simply isn’t enough capacity. Of course it wasn’t always like this: Manhattan’s population in the 1890s was the same as it is today, and it was clustered toward the southern third of the island, but employment was relatively evenly distributed in the downtown area. What has happened since then is that New York became a transit city.
There’s a strong correlation between the form of a city and the mix of transportation options people use. This extends well beyond density, but the principle is the same. Transit is at its best at high intensity, because this is what supports high-frequency service. Cars are the opposite: even on a normal urban street, a car alone will beat any rapid transit line, but every additional car will slow down the road dramatically, so that at even the moderate intensity of an edge city gridlock ensues.
Although usually this principle is stated in terms of density, it’s equally true for work centralization. The pedestrian city and the bus city will be dense all over, and feature high job density scattered across neighborhoods: walking is too slow for the transit city pattern to emerge, and buses have too little capacity. But dedicated rapid transit wants to serve an area right next to the stations, and once a network is built, a CBD grows around the central area. This CBD is typically small, just a few square kilometers. Even vaguely CBD-ish locations, such as Penn Station, are too far, as one commonly quoted figure about work locations demonstrates. The CBD isn’t even large enough to encompass all of the 34h-59th Street strip that the tourist guidebooks define as Midtown. The subway lines only form a tight mesh in a subset of that general area.
The job density of such a CBD is measured in hundreds of thousands per square kilometers, requiring many high-rise towers, several of which are supertall. In contrast, most of New York’s residences are mid-rise, and Tokyo’s are low- and mid-rise; their residential densities in the low tens of thousands per square kilometer are high enough that they are considered the epitome of density, but their CBDs are an order of magnitude denser.
Of the major transit cities of the world, Paris is the only one that’s resisted this trend with its height limit, but instead a transit-like CBD started out in La Défense, and the same pattern that comes from the subway in New York or Tokyo or the L in Chicago emerges with the RER. Of course, Paris maintains very high residential density, but its job distribution is more in line with that of a bus city – employment is dense all over, and the Downtown Paris employment density peak is less pronounced than in comparable transit city downtowns.
This does not mean a transit city needs to have empty trains going in the reverse-peak direction, as Cap’n Transit, Jarrett Walker, and others charge. A transit city will have job destinations outside the CBD, growing around rapid transit junctions: for example, Tokyo has Shinjuku, Shibuya, and Ikebukuro, all of which are so replete with high-rises it’s hard easy to forget they’re secondary job centers. While there is still a pronounced peak direction, people rely on transit so much that they take it for regular errands, supporting very high off-peak frequency by the standards of trains with drivers.
New York has something similar in Downtown Brooklyn, Jamaica, and Long Island City, but the modal split of those job destinations is much less favorable to transit – 50% in Downtown Brooklyn and Long Island City and 30% in Jamaica, according to a study of New York’s secondary job centers that I can no longer find. This is a general feature of many old American cities: the core looks like a transit city, but beyond it is a car-centric city, filled with edge cities and edgeless cities. Because the layout beyond the core is car-centric, the off-peak and reverse-peak traffic that supports high all-day bidirectional frequency on the Tokyo rail network, or for that matter on most New York City Subway lines, does not exist. The preference of American commuter rail agencies for peak-only service comes partly from an operating model that makes it impossible to run frequent off- and reverse-peak service, but also from a job distribution that makes the market for such runs small even under the best industry practice.
A corollary of this fact is that the multipolarity of other cities, for example Los Angeles, is not an asset. It would be an asset if those job centers were intense and could be easily served by transit; in reality, they have moderate intensity, nothing like that of the secondary centers of Tokyo or even New York, and serving many of them requires digging new subway lines. Burbank, on the legacy Metrolink network, could make a reasonable site for a transit-oriented secondary center, if commuter rail operations were modernized and local transit lines were extended to it; the Westside and Santa Monica do not, and the hope is that the investment in the Subway to the Sea could enable them to grow to reasonable size.
The key here is that the reason Shinjuku, Ikebukuro, and Shibuya are as transit-oriented as Central Tokyo is that they historically arose as connection points between the Yamanote Line and the private railroads. In particular, they already had rapid transit fanning out from multiple directions when they became major job centers. But Tokyo’s transit development history is peculiar; most other cities did not have large electrified rapid transit systems terminating at the edge of the urban core prior to building local subway lines.
A second corollary then is a strategy that sought to make New York a more transit-oriented city would treat centralization differently. It should turn the secondary centers into transit nodes in their own right, with tails extending as far out as reasonably possible. Jamaica already has some of the infrastructure, but it’s used poorly because of antiquated LIRR practices; the same can’t be said of Flushing, so a priority should be to build reasonable-quality transit from multiple directions, connecting Flushing with College Point and Jamaica and modernizing the LIRR so that it could connect it with Bayside.
A point that many people writing about this neglect (with pleasant exceptions like Cap’n Transit, the Streetsblog crowd, and Paul Barter) is that this requires both the carrot of more transit and the stick of less parking. In any case it’s hard to create high job densities when much of the land is used for parking. But on top of that parking mandates make it difficult for transit to be competitive when it’s expected to include railyards and depots in its budget and roads are not.
But what a transit city doesn’t need is job dispersal. The importance of creating secondary centers is strictly as alternatives to auto-oriented edge cities and edgeless cities, since whatever happens, not all jobs will be in the CBD. A large city with rapid transit connecting to all major neighborhoods will automatically have high transportation capacity. Rapid transit is good at transporting tens of thousands of people in one direction in the peak hour; let it do what it’s good at.
New York-New Rochelle Metro-North-HSR Compatibility
Let me preface this post by saying that there should not be any high-speed trains between New York and New Rochelle, except perhaps right at the northern end of the segment. However, to provide reasonable speeds from New York to Boston, it’s desirable to upgrade the maximum speed between New York and New Rochelle to 200 km/h or not much less. The subject of this post is how this can be accommodated while also permitting some regional rail service, as proposed by the MTA. There are two reasons to bundle the two. First, some of the work required could be shared: for example, new stations could be done at the same time as rail and tie replacement. And second, the presence of both upgraded intercity rail and regional rail on the line requires some four-tracking and schedule optimization.
The physical infrastructure required for boosting speeds within New York City is fairly minimal by itself. The right-of-way in the Bronx has some curves but they are not very sharp and can be somewhat straightened without knocking down buildings, and even the curves in Queens and on the Hell Gate Bridge, while unfixable without major viaduct modification, are not terrible if superelevation is high and tilting is enabled.
A big question mark is what the maximum speed permitted by the physical layout of the East River Tunnels is. Current speed is 97 km/h (60 mph), but top speed today in other sections of the network are below those achieved decades ago (for example on Portal Bridge), and trains with specially designed noses, as the Shinkansen rolling stock is, could potentially go even faster. Regardless, it is not important for HSR-regional rail integration, since the East River Tunnels have no stops and will be running far under capacity once East Side Access opens. Thus, all travel times in this post are between New Rochelle and Sunnyside Junction, which is notionally considered to be located at 39th Street. This is a 25-kilometer segment.
Another question mark is what the speed limit on the S-curve south of New Rochelle is. Currently the limit is 48 km/h (30 mph). Raising it requires grade-separating the junction between the NEC and the current New Haven Line. It can be raised further via curve straightening, but the question is how much eminent domain can be done. The maximum radius that can be achieved with minimal or no eminent domain is 700-800 meters. Some further eminent domain may be required to have this curve start far enough from the southbound platform that full 200 mm superelevation is achievable without subjecting local train riders to too much cant excess. For comparison, slicing through New Rochelle and the Pelham Country Club allows essentially eliminating the curve and allowing maximum speed through the area, which taking surrounding curves into consideration is about 240 km/h.
Assuming 150 km/h (about 700 meters radius, 200 mm cant, and 175 mm cant deficiency), the technical travel time for a nonstop intercity train between when it passes New Rochelle and when it passes Sunnyside is about 9 minutes; this includes slowdowns in Queens and the Bronx and on Hell Gate. A nonstop M8 with a top speed of 145 km/h would do the same trip in about 11:15. (Amtrak’s current travel time from New York to New Rochelle is about 25 minutes, of which by my observation riding Regional trains 6 are south of Sunnyside.)
Even the above travel time figures require some four-tracking, independently of capacity, in order to limit cant excess. Unlike the Providence Line, the Hell Gate line has some curves right at potential station locations – for example, the Hunts Point stop is located very close to the curve around the Bruckner Expressway, and the Morris Park stop is located in the middle of a curve. The Bruckner curve radius is about 500 meters, and 200 mm superelevation would impose 80 mm cant excess on even a fast-accelerating commuter train (1 m/s^2 to 72 km/h), and an uncomfortable 140 mm on a slower-accelerating one (0.5 m/s^2 to 51 km/h). The Morris Park curve is even worse, since it would impose a full 200 mm cant excess on a stopped train. So we should assume four-tracking at least at the Morris Park station, which is located in the middle of a curve, and Hunts Points, and potentially also at Parkchester.
Now, a local train would be stopping at New Rochelle and four stops in the Bronx, and should be stopping at Sunnyside. Although a FLIRT loses only about 75 seconds from a stop in 160 km/h territory, assuming 30-second dwell times, the M8 is a heavier, slower-accelerating train, and for our purposes we should assume a 90-second stop penalty. This means that, counting New Rochelle and Sunnyside together as a single dwell-free stop (they involve one acceleration and one deceleration in the Sunnyside-New Rochelle segment), local technical travel time is 18:15, about the same as what Amtrak achieves today without stops but with less superelevaiton and inferior rolling stock.
Now, 18:15-9 = 9:15, 9:15 times the schedule pad factor is 9:54, and modern signaling allows 2-minute headways up to 200 km/h; thus we can accommodate 4 tph intercity and 4 tph local Metro-North without overtakes except at New Rochelle and Sunnyside.
There is only one problem with the no-overtake scenario: the MTA plans on a peak traffic much higher than 4 tph, in line with the New Haven Line’s high demand. It’s planning on a peak of 6-8 tph according to what I’ve read in comments on Second Avenue Sagas. This naturally breaks into 4 tph that make local stops and 4 that do not (though my suspicion of MTA practice is that it wants fewer than 4 local tph); if there are fewer than 8 trains, one slot could be eliminated.
Let’s look then at a 4/4/4 scenario. Assume that trains depart Sunnyside in order of speed – HSR first (passing rather than stopping at Sunnyside), then express Metro-North, then local Metro-North. A local train will be overtaken first by the following HSR, and then by the following express. If we could move the overtake point to New Rochelle, the local would not need to wait for trains to pass it. In reality, 4/4/4 means the local departs Sunnyside 4-5 minutes after the HSR train passes it, and has 9 minutes of time penalty before being overtaken again. If the stop penalty could be reduced to 75 seconds, then the overtake could be moved to New Rochelle, demonstrating the use of top-quality rolling stock. But the M8s are good enough for many purposes, and therefore we will not assume a noncompliant replacement, unlike in the case of the MBTA, whose rolling stock is slow and very heavy.
With 9 minutes of time to make up, it’s tempting to have an overtake at a four-tracked Co-op City station. But then the local would have to be overtaken by two trains in a row, and moreover the two trains would become quite separated by then due to differing top speeds, and this would force a penalty on the order of 6 minutes.
I claim that the best would be to four-track a segment between two or even three stations; the right-of-way is wide enough anyway. In addition, the Morris Park curve could be straightened if the Eastchester Avenue overpass were modified, and doing this in conjunction with four-tracking would be cheaper than doing each alone. Under this option, the local would leave Sunnyside much later than 2 minutes after the express, just enough to be overtaken by HSR at Morris Park. It would then keep going to Co-op City until overtaken by an express. This would essentially save about 2.5 minutes out of the 6 in penalty, since the train would be in motion for that time.
New Rochelle-Penn Station Regional Rail
Last week, the MTA again floated proposals for connecting Metro-North to Penn Station once East Side Access comes online and frees track space currently used by the LIRR. The New Haven Line is to be connected to Penn Station via Northeast Corridor trackage that only Amtrak uses today, with four new stations in the Bronx. The new station locations include one near Co-op City, a dense middle-class housing project that is underserved by transit, and three more neighborhoods that are inconveniently between the 5 and 6 or on the wrong side of a freeway. In sum, it is a positive development.
However, since the New Haven Line already has a Manhattan terminal at Grand Central, this project involves splitting the line in two in its inner section. Thus, frequency will be cut in half, unless there is extra service added north of the merge point at New Rochelle. At the peak, this is not a very big problem, since the New Haven Line runs 20 trains into Grand Central between 8 and 9 am every weekday; although this is misleading since most stations are only served by a small subset of these trains, it is not difficult to have trains make a few more stops to restore the existing frequencies.
The problem is off-peak service. The current pattern is one train per hour serving stations north of Stamford and running nonstop between Stamford and Harlem-125th, and two Grand Central-Stamford locals per hour in the weekday off-peak and one on weekends. While poor by any international standards, the service afforded to the lower New Haven Line is tied for best in the US with just a handful of lines with half-hourly off-peak service. Splitting frequency in half would be a disaster for such service, to say nothing of not being useful to regional riders in the Bronx. Moreover, adding service just so that it can be split south of New Rochelle is counterproductive: the greatest need for frequency is close to the center rather than in the suburbs, because the shorter the trip time, the more pronounced the effect of a long wait time is.
I claim that the best way to compromise on frequency under the current service paradigm is to run short-turning trains terminating at New Rochelle, with timed connections. Since some passengers prefer a one-seat ride, half the local trains should serve Penn Station and half should serve Grand Central. In other words, frequency should be split among the two Manhattan destinations, but each branch should have a short-turning train connecting with the other branch’s trains. Express trains should make a station stop at New Rochelle with a reasonable connection from the local trains, but should otherwise only serve one destination. Then, Grand Central is the better destination for express trains, since it minimizes interference with intercity trains.
The alternative is to turn New Rochelle-Penn Station into a modernized regional rail line, run somewhat independently of the rest of Metro-North, with through-trains from the rest of the New Haven Line only at rush hour. Maybe select few off-peak trains, no more than 1 per hour, could extend to Stamford. This requires a change in paradigm; it cannot be done with the current staffing levels or turnaround times, but since it’s a service expansion, it’s plausible if unlikely that the union will accept reduced staffing, in line with best practices.
I envision the following scenario for modernized regional rail:
– Trains go from New Rochelle to Penn Station and beyond, to New Jersey. Through-service to the Hudson Line via the Empire Connection avoids agency turf battles but is less useful for passengers. They can hook into existing services and go all the way to Trenton and Long Branch, or provide new service and only go as far as Newark.
– Minimum off-peak frequency is one train every 15-20 minutes, or perhaps 30 late at night. 10 is aspirational, if the service proves popular.
– Fares are integrated with local transit. This means intra-city trips cost the same as subway or not much more, and in either case, transfers to the subway or the buses are free. If people can ride trains and a ferry from Tottenville to Wakefield on one fare, people should get to ride direct from Co-op City to Penn Station on one fare.
– Trains make stops that interface with other transit options. A Sunnyside stop meeting with the LIRR is a must. In addition, if the grades permit, there should be a stop in Astoria meeting the subway, and perhaps one in Port Morris, so that the trains can offer fast frequent service between Queens and the Bronx. Perhaps there should also be a restored station meeting buses from City Island.
The Sunnyside stop has value no matter what: for one, it allows trains to Penn Station to also work as Grand Central trains, making the transferring process easier to implement. The other extra stops are not really useful unless commuter rail is made an attractive option for local trips – in short, an S-Bahn or RER rather than a traditional American commuter service.
I hope to discuss compatibility with modernized intercity trains tomorrow. Although half-hourly service is so infrequent there is no real interference with intercity trains, more frequent service could pose problems. This is not an issue if Amtrak is not modernized: the speed limit south of New Rochelle is at most 160 km/h and even that is only between the Hutchinson River and Pelham Manor, with 100-110 km/h on the rest of the line. Thus the only speed difference between regional and intercity trains comes from making station stops, and a glance at existing schedules shows that when the top speed is 130-140 km/h trains lose about 1.5 minutes per stop. Of course high-powered noncompliant trains lose much less time, but for the purposes of running punctually on a shared line, the M8s are good enough. Losing 6 minutes from the four planned station stops is not a problem even with the proposed peak frequency, once one remembers that most peak trains are not going to stop in the Bronx at all.
Why the 7 to Secaucus Won’t Work
Bloomberg’s expressed support for the now $10-billion proposal to send the subway to Secaucus is generating buzz and speculation about the ability to secure funds. Missing from this discussion is any concern for whether more people would actually transfer at Secaucus than do today. The instinct is to say that this provides a better connection to most of Midtown, but the transfer penalty literature suggests otherwise.
One important thing to note, writes Reinhard Clever, is that for commuter rail, downtown-side transfers are much more inconvenient than suburb-side transfers. Suburban commuters will drive to a park-and-ride, but balk at a transfer at the city end. Clever’s example is Toronto, where commuter rail riders tend not to transfer to the subway at Union Station but only take transit to jobs that can be reached from the station by walking. This problem is what doomed the Austin Red Line. For all its flaws, ARC offered a one-seat ride from the Erie lines to Penn Station.
Another thing to note is that suburban commuters routinely change trains at Jamaica today, but not at Secaucus. I’m not aware of a study on the transfer experience, but I am fairly certain that the difference is that at Jamaica the transfers are timed and cross-platform whereas at Secaucus they are not. Transferring at Secaucus today involves going up steps, passing through faregates, and going down steps, with no guarantee of a connecting train. The literature is unanimous that passengers will spend more than one minute of in-vehicle time to avoid a minute of transfer or waiting time: the MTA uses a factor of 1.75, the MBTA 2.25, Houston METRO 3.5-4 (last two from pp. 31-2 of Clever’s thesis). None of this is going to change if people are instead made to transfer from a commuter train to the subway, except perhaps that the subway train is going to be less crowded because it won’t be carrying commuters from the Northeast Corridor and Morris and Essex Lines.
Both issues boil down to the same fundamental: not all transfers are created equal. Within urban rail, people transfer all the time. Perhaps the disutility of getting up while changing trains is not an issue when passengers do not expect to find a seat in the first place. Regional rail riders transfer as well, when the transfers are easy and there’s no additional waiting time – in fact, setting up a timed transfer on a highly branched regional line increases the frequency on each branch, so any disutility from transferring is swamped by the more convenient schedule. What people don’t normally do is ride a regional line that gets them almost to their job, and then take urban transit for the last mile.
Commuters on the Erie lines can already make an uncoordinated transfer involving passing through faregates at two locations: Secaucus, and Hoboken. Some, but not many, already take advantage of this to get to jobs near Penn Station or in Lower Manhattan. The contribution of the 7 to Secaucus would then be to create a third opportunity for a transfer to 42nd Street. While 42nd is closer to most Midtown jobs than Penn Station, the heart of Midtown is in the 50s. At Queensboro Plaza more inbound riders transfer from the 7 to the N/Q than the reverse, emptying the 7 by the time it gets to Manhattan: the MTA’s crowding estimate as reported by the Straphangers Campaign, has the taken at the entrance to the Manhattan core, ranks the 7 the least crowded subway line at rush hour. Thus, although the 7 to Secaucus would add to the number of jobs served by a two-seat ride, many Midtown jobs would require a three-seat ride, no different from transferring to the E at Penn Station.
Therefore, good transit activists should reject the 7 to Secaucus as they did ARC, and I’m dismayed to see NJ-ARP‘s Douglas John Bowen throw in his support behind it as an ARC alternative. Before anything else is done, the Secaucus faregates should be removed, and the platforms should be remodeled to let passengers go directly from the Erie platforms to the NEC platforms. Here are better candidate projects for adding a pair of tracks under the Hudson:
1. ARC Alt G. Despite the ARC cancellation, it remains the best option.
2. Hoboken-Lower Manhattan. This doesn’t give Erie commuters a one-seat ride to Penn Station, but compensates with a one-seat ride to Lower Manhattan, and a two-seat ride from the Morris and Essex Lines to Lower Manhattan. The Manhattan terminal should not be more than a two-track stub-end with short tail tracks and the potential for a connection to the LIRR Atlantic Division. With about 50 meters of tail tracks and a platform with many escalators, the Chuo Line turns nearly 30 tph on two tracks at Tokyo Station. It’s an outlier, but given the extreme cost of building larger stations in Manhattan, the response should not be “They’re different, our special circumstances won’t let this happen,” but “how can we have what they have?”. Modern signaling and punctuality are critical, but, as the Germans say, organization before electronics before concrete.
2b. Jersey City-Lower Manhattan. The same as option 2, but with somewhat less tunneling in Manhattan and a lot more tunneling in Jersey. The main advantage is that new underground stations at Journal Square and Exchange Place would serve more jobs and residents than a station in Hoboken. It may be cheaper due to reduced Manhattan tunneling, or more expensive due to less maneuvering room coming into Lower Manhattan. It also forces the Manhattan platform to be east-west rather than north-south for a far-future cross-platform transfer with Grand Central and Staten Island.
3. The L to Secaucus, or to Hoboken. This has all the problems of the 7 to Secaucus plus more – 14th Street is at best a secondary CBD – but it conveniently replaces the L’s current low-throughput terminal with another. Ideally the L should only be extended a few hundred meters west, to the Meatpacking District, but if such an extension has large fixed costs, the incremental cost of extending the L all the way could be low enough to be justified by the benefits of a Secaucus extension, which are low but nonzero.
Making Elevated Rail Work
Everybody hates els. They’re ugly and noisy and cities will even move their train station away from downtown to tear them down. The hypocritical treatment of els versus much wider and noisier elevated highways is fortunately the subject of another post, on Market Urbanism. I would instead like to discuss how elevated rail could be made to work in cities, allowing the construction of rapid transit at acceptable cost.
One way viaduct structures can be made more acceptable is if they’re branded as a new technology. This is the case of Vancouver’s SkyTrain, the JFK AirTrain, the Honolulu light rail line, and monorails. Another is if they’re along rights-of-way that are already considered blighted, such as freeways; this also helps explain why the JFK AirTrain was built whereas the proposed subway extension to LaGuardia was not.
As a first filter, the above examples suggest that the most useful elevated rapid transit – grade-separated mainline rail, or els over major streets – is impractical due to community opposition. But as a second filter, we could simulate some features of both cases in which viaducts are more acceptable – new technology and freeway right-of-way. If we build a well-designed and aesthetic arched viaduct over a wide road, this could pass community muster. For example, Robert Cruickshank prominently used the second and further photos in this CAHSR Blog post to argue that grade separations on the Peninsula will not be a blight. The 7 viaduct in Sunnyside is also a good example of an el.
As a third filter, the success of the elevated train over Queens Boulevard comes precisely from the enormous street width. East of Sunnyside, Queens Boulevard becomes practically a highway, nicknamed the Boulevard of Death and excoriated on Streetsblog for its lack of pedestrian scale. At the same time, the 7 above Roosevelt Avenue darkens the street and the steel el structure is very noisy. But when there is an el about Queens Boulevard, everything works out: the street is broken into two narrower halves, with the el acting as a street wall and helping produce human scale; the el is also farther from the buildings and uses an arched concrete structure, both of which mitigate its impact.
It’s possible to mitigate even further and imitate the methods of the AirTrain or SkyTrain. Those use modern viaduct construction techniques and are therefore relatively unobtrusive: see for example this photo on Greater City: Providence, in the context of reinstating some of the elevated infrastructure torn down in the 1980s. Even if the technology is your standard railroad, newer viaducts can reduce impact. In addition, the old els were built with very tight curves, producing squeal; building with wider curve radii is the norm today, and although it increases visual impact and can require more takings, it reduces noise impact, often to practically zero.
Commenters from various Northeastern suburbs have told stories of how people don’t even notice the electric regional trains, but complain about the freight trains. Of course those regional lines were built in the 19th century, but they were built to mainline standards, rather than to the standards of the Chicago L, and thus have what by rapid transit standards are wide curves.
The 7 el is 12 meters wide, and works fine on Queens Boulevard, which is 60 meters from building to building, and poorly on Roosevelt, which is 22. These give an upper and lower bound for street width. The N/W el on Astoria, at 12 meters over a 30-meter street, is also quite bad, though perhaps not as much as the 7 el on Roosevelt. The 1 el in Manhattanville is an imposing steel structure, but its problem is one of topography and height rather than street width, and so it should be put in the category of good els from the perspective of width; this is 12 meters over a 43-meter street. Finally, the Metro-North viaduct in Harlem is 18 meters over a 43-meter street; the area is quite blighted, though it could be a characteristic of the neighborhood more than of the el. Optimistically, it seems that a more modern two-track el, about 9 meters wide (and thus blocking light less than the New York examples regardless of street width), could work over a 30-meter street, such as the Manhattan avenues.
Of course, another issue is the surrounding density. Despite the above calculation I would not want to see new elevated lines on the Manhattan avenues. Partly this is because the population density in Manhattan is so high that the higher cost of a subway is acceptable. But partly it’s because the buildings are tall and would not pair off with the viaduct nicely as they do in Sunnyside. However, it could be a good solution in Queens and the North Bronx, where, additionally, the streets that could take rapid transit are wider than a standard Manhattan avenue.
The Tappan Zee Replacement’s Outrageous Cost
The Tappan Zee Bridge is about to fall down. As a result, the replacement and widening project is in spare-no-expense mode. Ordinarily, widening a bridge from seven lanes to ten would be judged in terms of costs and benefits, after which the costs would be ignored as they always are for US road projects. But now everyone thinks New York needs this project, to the point that even transit and livable streets advocates are more worried about commuter rail tracks on the new bridge than about the costs of the entire project.
Cap’n Transit cribbed study numbers before they disappeared from the official website. The budget of the project, without the transit component, was about $7 billion, and is now up to $8.3 billion; this includes highway widenings at both ends. The transit component people are fretting about is another $1 billion for BRT and $6.7 billion for commuter rail.
To put things in perspective, consider the Øresund Bridge-Tunnel complex. Whereas the Tappan Zee is 5 kilometers of bridge, Øresund consists of 8 kilometers of bridge, an artificial island with 4 additional kilometers of road, and 4 kilometers of tunnel. The cost, including landworks on both sides, was a little more than €3 billion in 2000, which works out to $5.5 billion in 2010. The bridge-tunnel is narrower than the Tappan Zee replacement – four lanes of traffic plus two tracks of rail – but it’s also three times as long, and more complex because of the tunnel.
More importantly, if the Tappan Zee really needs that capacity, and width is such a constraint, they should build rail first, BRT second, and car lanes last. Roads will never beat mass transit on capacity per unit width of right-of-way. With all traffic from Rockland to Westchester County funneled through one chokepoint, and some centralization of employment (in Manhattan, White Plains, and Tarrytown), rail could work if it were given the chance. So the only environment in which a bridge with so many traffic lanes is justified is one in which the cost of ten lanes is not much more than the cost of four.
To be completely fair to irate Rockland County residents, more people use the Tappan Zee than Øresund, since the tolls are lower and it’s a commuter route. But not enough. The bridge is crossed by 138,000 vehicles per day. This means the replacement and widening project, excluding all transit improvements, is $60,000 per car. With normal commuter seat occupancy, it’s perhaps $50,000 per person. Transit projects in the US routinely go over this, but those are for the most part very low-ridership commuter rail projects. Second Avenue Subway, the most expensive urban subway in the world per kilometer, is about $25,000 per expected weekday rider.
Given the high cost, the only correct response is a true no-build: dismantle the bridge, and tell people to ride ferries or live on the same side of the Hudson as their workplace. Given expected ridership and Øresund costs, I believe the Tappan Zee replacement would make sense at $3 billion, with the transit components; without, make it a flat $2 billion. Go much above it and it’s just too cost-ineffective. Not all travel justifies a fixed link at any cost.
Skewed North Shore BRT/LRT Proposal (Hoisted from Comments)
The MTA produced an alternatives analysis for transit service on the North Shore of Staten Island. The study contains zingers and various factors making the cost many times higher than it should be, but the agency response to all comments is Decide, Announce, Defend. Commenter Ajedrez reports from a public meeting on the subject on Second Avenue Sagas:
I went for part of the meeting (from about 18:30 to 19:45), and this is a rundown of what happened:
* They discussed the updates from the last meeting. They eliminated the ferry option (that didn’t even make sense), and they eliminated the heavy rail option.
* The people were given the opportunity to ask questions and make comments. This one woman (the same woman from last time) ranted on and on about something historical at Richmond Terrace/Alaska Street that would be destroyed if they paved over it.
Then a few more people made some comments, and I asked why they eliminated the heavy rail option (for those of you who are wondering, I was the kid in the yellow jacket and blue/black striped shirt. Then again, I was the only kid in the room)
* Then we went to the back to talk with the people from the consulting firm. I discussed the heavy rail more in depth, and asked why it was needed if the West Shore Light Rail would supposedly cover the Teleport. I then made a couple of suggestions for the short-term (reverse-peak S98 service, my S93 extension, cutting back more S46s to Forest Avenue) and I gave them the name of a person at the MTA who they could contact.
To elaborate on my statement about heavy rail, they said that they took it completely off the table. It just amazed me that they originally had a ferry line as one of the options, but they didn’t even have heavy rail as an option south of Arlington.
Let me think, you have an abandoned rail line (and a heavy rail line at that), and you want to put a ferry line there. What sense does that make? I could understand maybe having the ferry supplement the rail line, but doing that would have the whole thing go to waste.
I said that the current SIR is heavy rail and the South Shore is more auto-oriented than the North Shore. And I said that it provides better integration with the current SIR (they said they could put light rail in the Clifton Yard, but it’s probably automatically cheaper if you don’t have to retrofit the yard). And I also said that there’s higher capacity than light rail, so in case there’s growth, it is better equipped to handle it
So they said “Well, it was too expensive (because one of the goals was to serve the Teleport) so we didn’t even consider it.” And then they said that SI doesn’t have Brooklyn-type density to support heavy rail (but somehow the South Shore does?). And if you limit it to light rail, you’re actually limiting SI’s growth potential. Think about it: before 1900, Brooklyn had some streetcar lines, but not a whole lot of ridership. When the subway was extended, the population exploded. But if they just extended some streetcar lines from Brooklyn to Manhattan, the population would be nowhere near the 2.5 million it has today.
And then they said “Oh, well during the last meetings (which I attended, so I know they’re not being completely truthful) people expressed a sentiment for light rail”. They didn’t. They expressed a sentiment against a busway, There’s a difference. They didn’t say “Oh, it shouldn’t be heavy rail”. They just said they want rail rather than buses.
I mean, the argument I should’ve made (besides the ones I already did) was the fact that there was heavy rail there before, and the population was smaller back then. I think it’s pretty obvious.
And when I made that statement, everybody was surprised at how young I was (16). One woman said “You should be the one studying this project”, and they actually tried to avoid responding to me (they were like “Thank you. Next question”, and then everybody said “But you didn’t answer his question”, and that’s when they made up the response about expenses)
Besides the wretched DAD attitude, the cost projections and the route choice doesn’t even make sense. The proposal is to use the abandoned B&O right-of-way along the North Shore, from St. George to Arlington, and then cut over to South Avenue and serve West Shore Plaza. Here is satellite imagery of South Avenue: observe that it is almost completely empty.
Here we have a line that consists of 8.5 kilometers of abandoned trackage, which can be restored for service remarkably cheaply, and 5.5 of an on-street segment, which tends to be much more expensive to construct. Compare the costs of regional rail restoration in Germany or Ottawa’s O-Train with those of French LRT lines (including Lyon’s cheaper line). In addition, the areas along the abandoned trackage are of moderate density by non-New York standards, while those along South Avenue aren’t even suburban. And yet, the MTA is convinced that the per-km cost of an option that terminates at Arlington is higher than that of an option that goes to West Shore Plaza ($56 million/km vs. $41/km).
While the cost range proposed is only moderately high for light rail – the French average is a little less than $40 million/km – this is misleading because of the nature of the lines. French tramways tend to be on-street, involving extensive street reconstruction. Sometimes they need a new right-of-way along a boulevard or a highway. In contrast, the North Shore Branch is a mostly intact rail right-of-way, which means that the land grading and the structures, the most expensive parts of any rail project, are already in place. It shouldn’t cost like a normal light rail project; it should cost a fraction.
On top of this, to inflate the cost, the MTA is talking about a train maintenance shop. It says a light rail option allows merely modifying the maintenance shop for the Staten Island Railway. Not mentioned is the fact that SIR-compatible heavy rail would allow the trains to be maintained in the same shops without modification, to say nothing of leveraging New York City Transit’s bulk buying to obtain cheaper rolling stock.
The O-Train’s cost – C$21 million for 8 km of route – included three three-car DMUs, piggybacking on a large Deutsche Bahn order; judging by the cost of a more recent expansion order from Alstom, a large majority of the original $21 million was rolling stock. New York should be able to obtain cheaper trains, using its pricing power and sharing spares with the SIR. The electrification costs would add just a little: electrification can be done for €1 million per route-km, and in high-cost Britain it can be done for £550,000-650,000 per track-km (p. 10).
For an order of magnitude estimate of the cost of a well-designed SIR-compatible North Shore Branch, we have, quoting my own comment on SAS:
For an order-of-magnitude estimate of what’s needed, figure $20 million for electrification, $5 million for high-platform stations, and $25 million for six two-car trains plus a single spare. Go much higher and it’s not a transportation project, but welfare for contractors.
In retrospect would add about $10-20 million for trackwork, since the line is abandoned. On the other hand, fewer trains could be used: I was assuming 10-minute headways and a 25-minute travel time to Port Ivory; with 15-minute headways and a travel time under 17.5 minutes to Arlington, which is realistic given subway speeds (the MTA study says 15), only three trains plus a spare would be required.
On a related note, the loading gauge excluding station platform edges should be rebuilt to mainline standards, to allow future regional rail service to replace the SIR. Eventually Staten Island is going to need a long tunnel to Manhattan or Brooklyn if it’s to look like an integral part of the city, and once such a tunnel is built, it might as well be used to provide RER-style service across the city.
In contrast, the MTA proposal has no concern for cost cutting, and looks like lip service to the community. It’ll be an especial tragedy if the line is permanently ripped up to make room for a busway, which will likely underperform and turn into a highway. The contractors are going to get well paid no matter what: the busway is cheaper, but not by an order of magnitude. It’s just the riders who will not have good transit on Staten Island’s North Shore.
Quick Note: ACS 2010
The Census Bureau has just released the American Community Survey numbers for 2010, using data calibrated to match with the 2010 census. At least, calibration is the best reason for why the ACS believes that New York went from 8,391,881 people in 2009 to 8,184,899 in 2010 (according to the new Factfinder). Because of such jarring discrepancies in results, people should under no circumstances directly compare numbers from the 2010 ACS with numbers from previous ACSes.
The best demographic survey in the US is still the 2009 ACS, which avoids the whopper claim that New York added more housing units than people at a time of skyrocketing rents, and should be used until it becomes completely outdated.
And even if 2010 census data is at all reliable, it’s still not directly comparable. Claims about absolute mode share or commute time are okay (the census after all only underestimated New York’s population by about 3%), but claims about change from 2009 are not. At best the 2010 ACS should be compared to the 2000 estimate base, and even that is strained – too much reliance on a census that doesn’t count everyone, insufficient reliance on years of rigorous statistical sampling.
Pedestrian Observations 
