As some American cities are attempting to reduce the number of car accident fatalities, under the umbrella of Vision Zero, the growing topic is one of traffic enforcement. Streetsblog has long documented many instances in which the police treats any case in which a car runs over a pedestrian as a no-fault accident, even when the driver was committing such traffic violations as driving on the sidewalk. In addition to enforcement, there’s emphasis on reducing the speed limit in urban areas, from 30 to 20 miles per hour, based on past campaigns in Europe, where speeds were reduced from 50 km/h to 30. Unfortunately, street design for lower speeds and greater traffic safety has taken a back seat. This is not the best way to improve street safety, and is not the standard practice in the countries that have reduced car accident rates the most successfully, namely the UK and the Scandinavian countries.
On high-speed roads, one of the most important causes of fatal accidents is the combination of driver fatigue and sleepiness. For some studies on this problem, see here, here, and here. The second link in particular brings up the problem of monotony: if a road presents fewer stimuli to the driver, the driver is more likely to become less vigilant, increasing the probability of an accident. One study goes on and shows that higher speed actually increases monotony, since drivers have less time to register such stimuli as other cars on the road, but this was obtained in controlled conditions, and its literature review says that most studies find no effect of speed. I emphasize that this does not mean that lower speed limits are ineffective: there’s evidence that reducing highway speed limit does reduce accident rates, with multiple studies collected in a Guardian article, and lower accident rates in France since the state installed an extensive system of speed cameras.
But while speed limit reductions offer useful safety benefits, it is important to design the roads to be slower, and not just tell drivers to go slower. Road monotony is especially common in the United States; per the second study again,
While comparing self-reported driving fatigue in the US and Norway, Sagberg (1999) suggests that the higher prevalence of self reported drowsy driving found in the US may be due to differences in road geometry, design and environment, as well as exposure. He argues that the risk of falling asleep is higher on straight, monotonous roads in situations of low traffic, where boredom is likely to occur. This type of roads is more common in the US than in Norway.
The studies I have consulted look primarily at highways and rural roads; I have not found comparable literature on urban roads, except one study that, in a controlled simulation, shows that drivers are better at gauging their own alertness levels on urban arterials than on rural roads. That said, urban arterials share many design traits that lead to monotony, especially in the United States and Canada:
- They are usually straight, forming a grid rather than taking haphazard routes originating from premodern or early-industrial roads.
- They are wide: 4-6 lanes at a minimum, often with a median. Lanes are likely to be wide, closer to 3.7 meters than the more typical urban 3 meters.
- Development on them usually does not form a strong enclosure, but instead commercial developments are only 1-2 stories, with setbacks and front and side parking lots.
Such roads are called stroads in the language of Charles Marohn, who focuses on issues of their auto-centric, pedestrian-hostile nature. Based on the studies about monotony, I would add that even ignoring pedestrians entirely, they are less safe than slower roads, which prime drivers to be more alert and to speed less. It is better to design roads to have more frequent stimuli: trees, sidewalks with pedestrians, commercial development, residential development to the extent people are willing to live on top of a busy road.
Regarding lane width, one study finds that roads are the safest when lanes are 3-3.2 meters wide, because of the effects of wider lanes on driver speeds. A CityLab article on the same subject from two years ago includes references to several studies that argue that wide lanes offer no safety benefit for drivers, but are hostile to pedestrians and cyclists.
This approach, of reducing speed via road design rather than enforcement, is common in Scandinavia. Stockholm has a few urban freeways, but few arterials in the center, and many of those arterials have seen changes giving away space from cars to public transit and pedestrians. Thus, Götgatan is partly pedestrianized, and Odengatan has center bus lanes and only one moving car lane in each direction; the most important of Stockholm’s streets, Sveavägen, has several moving car lanes in each direction, but is flanked on both sides by medium-rise buildings without setbacks, and speeds are rarely high.
When enforcement happens, the great successes, for example in France under the Sarkozy administration, involve automation. Red light cameras have a long history and are controversial, and in France, Sarkozy lowered the speed limits on many roads and stepped up speed camera enforcement. The UK has extensive camera enforcement as well. Human enforcement exists, but is less common than speed cameras. Thus, the two main policy planks Vision Zero should fight for in the US are,
- Road redesign: narrower lanes, wider sidewalks, trees, and dedicated bus and bike lanes in order to reduce the number of car lanes as well as provide more room for alternatives. Zoning laws that mandate front setbacks should be repealed, and ideally so should commercial height limits on arterials. In central cities, some road segments should be closed off to cars, if the intensity of urban activities can fill the space with pedestrians.
- Lower speed limits in the cities, enforced by cameras; fines should be high enough to have some deterrent effect, but not so high that they will drive low-income drivers bankrupt.
It is especially important to come up with solutions that do not rely on extensive human enforcement in the US, because of its longstanding problem with police brutality and racism. The expression “driving while black” is common in the US, due to bias the police in the US (and Canada) exhibits against black people. In Europe, even when bias against certain minorities is as bad as in the US, overall police brutality levels are lower in the US by factors ranging from 20 to 100 (see for example data here). In my Twitter feed, black American urbanists express reluctance to so much as call the police on nonviolent crime, fearing that cops would treat them as suspects even if they are the victims. When it comes to urban traffic safety – and so far, Vision Zero in the US is an urban movement – this is compounded by the fact that blacks and other minorities are overrepresented in the cities.
This means that, in the special conditions of US policing, it’s crucial to prevent Vision Zero from becoming yet another pretext for Driving While Black arrests. As it happens, it does not require large changes from best practices in Europe, because those best practices do not involve extensive contact between traffic police and drivers.
Recall last year’s post by Adonia Lugo, accusing Vision Zero of copying policy from Northern Europe and not from low-income American minority communities. As I said a year ago, Adonia is wrong – first in her belief that foreign knowledge is less important than local US knowledge, and second in her accusation that US Vision Zero advocates copy European solutions too much. To the contrary, what I see is that the tone among US street safety advocates overfocuses on punitive enforcement of drivers who violate the speed limit or break other law. Adapting a problem that in Europe is solved predominantly with street design and technology (speed cameras don’t notice the driver’s skin color), they instead call for more policing, perhaps because mainstream (i.e. white) American culture is used to accepting excessive police presence.
A number of major cities, most notably London, have designated areas around their built-up areas as green belts, in which development is restricted, in an attempt to curb urban sprawl. The towns within the green belt are not permitted to grow as much as they would in an unrestricted setting, where the built-up areas would merge into a large contiguous urban area. Seeking access to jobs in the urban core, many commuters instead live beyond the greenbelt and commute over long distances. There has been some this policy’s effect on housing prices, for example in Ottawa and in London by YIMBY. In the US, this policy is less common than in Britain and Canada, but exists in Oregon in the form of the urban growth boundaries (UGBs), especially around Portland. The effect has been the same, replacing a continuous sprawling of the urban area with discontinuous suburbanization into many towns; the discontinuous form is also common in Israel and the Netherlands. In this post, I would like to explain how, independently of issues regarding sprawl, such policies are friendlier to drivers than to rail users.
Let us start by considering what affects the average speed of cars and what affects that of public transit. On a well-maintained freeway without traffic, a car can easily maintain 130 km/h, and good cars can do 160 or more on some stretches. In urban areas, these speeds are rarely achievable during the day; even moderate traffic makes it hard to go much beyond 110 or 120. Peak-direction commutes are invariably slower. Moreover, when the car gets off the freeway and onto at-grade arterial roads, the speed drops further, to perhaps 50 or less, depending on density and congestion.
Trains are less affected by congestion. On a well-maintained, straight line, a regional train can go at 160 km/h, or even 200 km/h for some rolling stock, even if headways are short. The busiest lines are typically much slower, but for different reasons: high regional and local traffic usually comes from high population density, which encourages short stop spacing, such that there may not be much opportunity for the train to go quickly. If the route is curvy, then high density also makes it more difficult to straighten the line by acquiring land on the inside of the curves. But by and large, slowdowns on trains come from the need to make station stops, rather than from additional traffic.
Let us now look at greenbelts of two kinds. In the first kind, there is legacy development within the greenbelt, as is common around London. See this example:
The greenbelt is naturally in green, the cities are the light blue circles with the large central one representing the big city, and the major transportation arteries (rail + freeway) are in black. The towns within the greenbelt are all small, because they formed along rail stops before mass motorization; the freeways were built along the preexisting transportation corridors. With mass motorization and suburbanization, more development formed right outside the greenbelt, this time consisting of towns of a variety of sizes, typically clustering near the freeways and railways for best access to the center.
The freeways in this example metro area are unlikely to be very congested. Their congestion comes from commuters into the city, and those are clustered outside the greenbelt, where development is less restricted. Freeways are widened based on the need to maintain a certain level of congestion, and in this case, this means relatively unimpeded traffic from the outside of the green belt right up until the road enters the big city. Under free development, there would be more suburbs closer to the city, and the freeway would be more congested there; travel times from outside the greenbelt would be longer, but more people would live closer to the center, so it would be a wash.
In contrast, the trains are still going to be slowed down by the intermediate stops. The small grandfathered suburbs have no chance of generating the rail traffic of larger suburbs or of in-city stops, but they still typically generate enough that shutting them down to speed traffic is unjustified, to say nothing of politically impossible. (House prices in the greenbelt are likely to be very high because of the tight restrictions, so the commuters there are rich people with clout.) What’s more, frequency is unlikely to be high, since demand from within the greenbelt is so weak. Under free development, there might still be more stops, but not very many – the additional traffic generated by more development in those suburbs would just lead to more ridership per stop, supporting higher frequency and thus making the service better rather than worse.
Let us now look at another greenbelt, without grandfathered suburbs, which is more common in Canada. This is the same map as before, with the in-greenbelt suburbs removed:
In theory, this suburban paradigm lets both trains and cars cruise through the unbuilt area. Overall commutes are longer because of the considerable extra distance traveled, but this distance is traversed at high speed by any mode; 120 km/h is eminently achievable.
In practice, why would there be a modern commuter line on any of these arteries? Commuter rail modernization is historically a piecemeal program, proceeding line by line, prioritizing the highest-trafficked corridors. In Paris, the first commuter line to be turned over to the Metro for operation compatible with city transit, the Ligne de Sceaux, has continuous urban development for nearly its entire length; a lightly-trafficked outer edge was abandoned shortly after the rest of the line was electrified in 1938. If the greenbelt was set up before there was significant suburbanization in the restricted area, it is unlikely that there would have been any reason to invest in a regional rail line; at most there may be a strong intercity line, but then retrofitting it to include slower regional traffic is expensive. Nor is there any case for extending a high-performing urban transit line to or beyond a greenbelt. Parts of Grand Paris Express, namely Lines 14 and 11, are extended from city center outward. In contrast, in London, where the greenbelt reduces density in the suburbs, high investment into regional rail focuses on constructing city-center tunnels in Crossrail and Crossrail 2 and connecting legacy lines to them. In cities that do not even have the amount of suburban development of the counties surrounding London, there is even less justification for constructing new transit.
Now, you may ask, if there’s no demand for new urban transit lines, why is there demand for new highways? After all, if there was not much regional travel into these suburbs historically, why would there be enough car traffic to justify high investment into roads? The answer is that at low levels of traffic, it’s much cheaper to build a road than to build and operate a railway. This example city has no traffic generators in the greenbelt, except perhaps parks, so roads are cheap to build and have few to no grade crossings to begin with, making it easier to turn them into full freeways. The now-dead blog Keep Houston Houston made this point regarding a freeway in Portland, which was originally built as an arterial road in a narrow valley and had few at-grade intersections to be removed. At high levels of demand, the ability to move the same number of people on two tracks as on fourteen lanes of freeway makes transit much more efficient, but at low demand levels, rail still needs two tracks or at least one with passing sidings, and high-speed roads need four lanes and in some cases only two.
The overall picture in which transit has an advantage over cars at high levels of density is why high levels of low-density sprawl are correlated with low transit usage. But I stress that even independently of sprawl, greenbelts are good for cars and bad for transit. A greenbelt with legacy railway suburbs is going to feature trains going at the normal speed of a major metro area, and cars going at the speed of a more spread out and less populated region. Even a greenbelt without development is good urban geography for cars and bad one for transit.
As a single exception, consider what happens when a greenbelt is reserved between two major nodes. In that specific case, an intercity line can more easily be repurposed for commuting purposes. The Providence Line is a good example: while there’s no formal greenbelt, tight zoning restrictions in New England even in the suburbs lead to very low density between Boston and Providence, which is nonetheless served by good infrastructure thanks to the strength of intercity rail travel. The MBTA does not make good use of this infrastructure, but that’s beside the point: there’s already a high-speed electrified commuter line between the two cities, with widely spaced intermediate stops allowing for high average speeds even on stopping trains and overtakes that are not too onerous; see posts of mine here and here. What’s more, intercity trains can be and are used for commutes from Providence to Boston. For an analogous example with a true greenbelt, Milton Keynes plays a role similar to Providence to London’s Boston.
However, this exception is uncommon. There aren’t enough Milton Keyneses on the main intercity lines to London, or Providences on the MBTA, to make it possible for enough transit users to suburbanize. In cities with contiguous urban development, such as Paris, it’s easier. The result of a greenbelt is that people who do not live in the constrained urban core are compelled to drive and have poor public transportation options. Once they drive, they have an incentive to use the car for more trips, creating more sprawl. This way, the greenbelt, a policy that is intended to curb sprawl and protect the environment, produces the exact opposite results: more driving, more long-distance commuting, a larger urban footprint far from the core.
Following plans by the government of Norway to ban cars fueled by petrol or diesel by 2025, several other countries in Europe are formulating similar programs to phase out fuel-powered transportation. Moreover, sources close to the European Parliament say that once multiple member states pass such a ban as is expected later this year, the European Union will attempt to enforce these rules throughout its territory.
In Sweden, the office of Åsa Romson, minister for the environment and co-spokesperson for the Green Party, released a statement saying that a ban on the internal combustion engine is a necessary step to reduce pollution and carbon emissions. In Sweden, only about 3% of electricity production comes from fossil fuels, and plans made by the Persson cabinet in 2005, Making Sweden an Oil-Free Society, already call for a phaseout of the use of oil for heating. The Löfven cabinet has nowhere else to cut in its program to make Sweden a carbon-neutral society by 2050. The Social Democrats-Green minority government is expected to work with the more moderate parties in the opposition Alliance; the Centre Party has already endorsed the move, but the Liberals have yet to make a statement.
In France and Germany, the ban is expected to be far more contentious. Auto manufacturers in both countries have condemned the moves by their respective governments to ban the internal combustion engine, saying that it would make the economy less competitive. European automakers have lagged behind Japanese and American ones in both hybrid and all-electric car technology, as conventional European petrol and diesel cars already have high fuel economy. In response to so-called range anxiety, in which an electric car’s limited range may leave the driver stranded on the motorway, the Hollande administration is expected to pair the proposed phaseout with national investment into charging stations as well as additional investment into TGV lines, to make it easier to travel long distances in France without a car.
Demands by BMW and Volkswagen for Germany to commit to spending money on R&D for improved battery range and charging and battery swap stations on the highway network have run into budgetary problems. While Chancellor Angela Merkel is reported to be interested in implementing a phaseout, in order to attract Green support into a possible future grand coalition and reduce EU dependence on oil imports from Russia, Finance Minister Wolfgang Schäuble has openly rejected any package that would raise the budget deficit, and the allied Christian Social Union has rejected the proposed ban on principle. Opposition from far-right populist parties, including the Alliance for Germany (AfD) and France’s National Front (FN), is likely to be significant, and sources close to Hollande and Merkel say that both have ruled out tax increases to pay for the program.
In France the calls for a phaseout of the internal combustion engine are especially loud in the Paris region, where high levels of particulate pollution from diesel vehicles led to recent restrictions on car use. The mayor of Paris, the Socialist Anne Hidalgo, previously proposed to ban diesel vehicles from the city entirely, and has endorsed the state’s plans to phase out fuel-powered vehicles, adding that given Paris’s pollution crisis, a local ban on diesel vehicles should be implemented immediately. The president of the regional council, Valérie Pécresse of the Republicans (LR), is said to support the phaseout as well, and to push LR behind the scenes not to oppose it. Conversely, opposition from FN is especially acute. The party leader, Marine le Pen, quipped that France would not need any additional reductions in greenhouse gas emissions if it had not taken in non-European immigrants since the 1960s, and noted that the immigrants are especially likely to settle in Paris, where the problems are the most acute.
Elsewhere in Europe, Belgium, Switzerland, and the Netherlands are said to be considering a phaseout by 2030. Within Belgium, Saudi support of mosques preaching radical interpretations of Islam is said to have influenced the country’s liberal parties, the Francophone Reformist Movement (MR) and the Flemish Liberals and Democrats (VLD), to support a phaseout. However, the Flemish nationalist parties remain opposed, and the New Flemish Alliance (N-VA) issued a statement saying that this solution may work within Brussels but is inappropriate for Flanders. In contrast, the Netherlands is expected to pass the phaseout without any political problems. In Switzerland, a referendum is planned for next year, and early polling suggests that it is supported by 55-60% of the population.
Governments outside Europe are said to be watching the development closely, especially in France and Germany, which are perceived as more reliable bellwethers of European opinion than Sweden. In Japan, home to the world’s top-selling electric car, the Nissan Leaf, political support for a phaseout appears high. Prime Minister Shinzo Abe has called climate change a “defining issue of our time,” and is working on a national infrastructure plan. Sources close to Abe say it will pair subsidies for so-called city cars, short-range electric vehicles, with investments into the country’s rail network outside major metropolitan areas, to make it easier for people living outside the biggest cities to travel on public transport.
In the US, both the Obama administration and Hillary Clinton’s presidential campaign refused to comment, saying that it is an internal European affair. However, sources close to the administration say that it is already planning to use the Environmental Protection Agency’s executive power to restrict the sale of new fuel-powered cars to emergency needs. The sources speculate that an executive order is planned for shortly after the presidential election this November, provided Clinton wins, in order to avoid creating backlash among key swing constituencies, including the automakers and the exurban lower middle class. Donald Trump’s presidential campaign’s response is unprintable.
This is somewhat of an addendum to my post before about dispersal of urban networks toward cheaper cities. I addressed the question of dispersal from rich, expensive metro areas, especially San Francisco, to cheaper ones, as a way of dealing with high housing prices. But more common is dispersal within metro areas: gentrification spilling from a rebounding neighborhood to adjacent neighborhoods that remain cheaper, and office space spilling from the primary CBD to the edge cities. I am going to address the latter issue in this post.
CBDs are expensive. They have intense demand for office space, as well as high-end retail and hotels. In many cities, there’s demand for office space even at the construction costs of supertall skyscrapers, going up to about $5,000-6,000 per square meter in privately-built New York towers. Zoning regimes resist the height required to accommodate everyone, and this is worse in Europe than in North America and high-income East Asia. Paris proper has many towers just above the 100 meter mark, but only three above 120. On a list of the tallest buildings in Sweden, not a single one above 100 meters is in central Stockholm, and the tallest within the zone are not in the CBD but in Södermalm; compare this with Vancouver, a metro area of similar size. But in the US, too, expanding CBDs is difficult in the face of neighborhood opposition, even in Manhattan.
The solution many cities have adopted is to put the skyscrapers in edge cities. Paris famously built La Defense, which has far more skyscrapers than the city proper does; Stockholm is building skyscrapers in Kista; London built Canary Wharf; Washington, the major US city with the tightest CBD height limits, sprouted skyscraper clusters in several suburbs in Maryland and Virginia. Ryan Avent proposed this as one solution to NIMBYism: in new-build areas, there are few residents who could oppose the new development. In contrast, near zoning-constrained CBDs, not only are there many residents, but also the land is so desirable that they are typically high-income, which means they have the most political power to oppose new development.
The problem with this solution is that those secondary CBDs are not public transit hubs. In Paris, this has created an east-west disparity, in which people from (typically wealthy) western suburbs can easily reach La Defense, whereas people from poorer ones need to take long RER trips and often make multiple transfers. In every transit city, the CBD is unique in that it can be reached from anywhere. To give similar accessibility to a secondary center, massive investment is required; Paris is spending tens of billions of euros on circumferential regional rail lines to improve suburb-to-suburb connectivity, expand access in the eastern suburbs, and ameliorate the east-west imbalance (see for example isochrones on PDF-pp. 20-21 of the links here). Those lines are going to be well-patronized: the estimate is 2 million daily passengers. And yet, the east-west imbalance, if nothing else, would be a lesser problem if instead of building La Defense, Paris had built up Les Halles.
The situation in other cities is similar. Kista is on one branch of one subway line, two stops away from its outer terminus. Living in Central Stockholm, my coworkers and I can get to KTH on foot or by bike, but a coworker who teaches at KTH’s satellite campus in Kista has a long commute involving circumferential buses (taking the subway and changing at T-Central would be even longer because of the detour). While many individual sub-neighborhoods of Central Stockholm are quite dense, the overall density in the center is not particularly high, certainly not by the standards of Paris or New York. A similar problem happens in Washington, where the biggest edge city cluster, Tysons Corner, is traditionally auto-oriented and was only just connected to Metro, on a branch. This always affects poorer people the worst, as they can’t afford to live in the CBD, where there is easy access to all secondary destination, and often are pushed to suburbs with long commutes.
There is a political economy problem here, as is usually the case with zoning. (Although in the largest cities skyscraper heights are pushing beyond the point of constant marginal costs, purchase prices at least in New York are much higher than construction costs.) The people living near CBDs, as noted before, are usually rich. The displacement of office space to the suburbs affects them the least, for three reasons. First, if they desire work within walking distance or short subway distance, they can have it, since their firms typically make enough money to afford CBD office rents. Second, since they live in the transit hub, they can access suburban jobs in any direction. And third, if the transit options are lacking, they can afford cars, although of course traffic and parking remain problematic. Against their lack of incentive to support CBD office space, they have reasons to support the status quo: the high rents keep it exclusive and push poor people away, and often the traditional mid-rise buildings are genuinely more aesthetic than skyscrapers, especially ones built in modernist style.
These concerns are somewhat muted in the US, where rich people decamped for the suburbs throughout the 20th century, and have supported zoning that mandates single-family housing in the suburbs, instead of staying in the city and supporting zoning that keeps the city mid-rise. This may have a lot to do with the formation of high-rise downtowns in American cities of such size that in Europe they’d be essentially skyscraper-free.
However, what’s worse in the US is the possibility of short car-free commutes to the edge cities. Where La Defense is flanked by suburbs with high residential density, and Kista’s office blocks are adjacent to medium-density housing projects for working- and middle-class people, American edge cities are usually surrounded by low-density sprawl, where they are easily accessible by car but not by any other mode of transportation. This is because the American edge cities were usually not planned to be this way, but instead arose from intersections of freeways, and developed only after the residential suburbs did. As those edge cities are usually in rich areas, the residents again successfully resist new development; this is the point made in Edgeless Cities, which notes that, in major US metro areas, growth has been less in recognizable edge cities and more in lower-density edgeless cities.
As with the possibility of dispersing innovation clusters from rich, expensive metro areas to poorer and cheaper ones, the already-occurring dispersal from city centers to edge and subsequently edgeless cities has negative effects. It lengthens transit commutes. Although in Tokyo, long commutes first arose as a problem of a monocentric CBD, and the city developed secondary CBDs as a solution, the situation in European cities an order of magnitude smaller is very different. It worsens housing segregation: the development of an edge city tends to be in the direction of the favored quarter, since that’s where the senior managers live, and conversely, higher-income workers can choose to move nearby for the short commute. Although nearly all metro areas have favored quarters, decentralization of jobs thus tends to lengthen the commutes of poor people more than those of rich people.
This is not quite the same as what happens when entire metro areas are forced to disperse due to housing cost. The agglomerations generally stay intact, since an entire industry can move in the same direction: smaller cities have just one major favored quarter with edge cities, and larger ones still only have a few, so that industries can specialize, for example in New York, biotech and health care cluster in the Edison-Woodbridge-New Brunswick edge city. Moreover, the specialized workers are usually high-income enough that they can stay in the central city or migrate to the favored quarter. San Francisco’s programmers are not forced to move individually to faraway poor neighborhoods; they move in larger numbers to ones near already gentrifying ones, spurring a new wave of gentrification in the process; were they to move alone, they’d lose the access to the tech shuttles. The negative effects are predominantly not on richer people, but on poorer people.
The problem is that even among the poor, there is little short-term benefit from supporting upzoning. If Paris, London, and Stockholm liberalize housing and office construction, the first towers built of both kinds will be luxury, because of the large backlogs of people who would like to move in and are willing to pay far in excess of construction costs. I am going to develop this point further in two posts, on what is best called NITBYism – Not In Their Backyard – but this means that the incentive for poor and peripheral populations is not to care too much about development in rich centers. The marginal additional building in a rich city center is going to go to the upper middle class; sufficient construction would trickle to the middle class; only extensive construction would serve the working class, and then not all of it.
In the US, the marginal additional building may actually displace poor people, if no new construction is allowed, simply by removing low-income apartments. It may even create local demand for high-income housing, for example by signaling that the neighborhood has improved. In San Francisco, this is compounded by the tech shuttles, as a critical mass of Silicon Valley-bound residents can justify running shuttles, creating demand for more high-income housing.
The amount of construction required to benefit the bottom half of the national income distribution is likely to be massive. This is especially true in France and the UK, which have sharp income differences between the capital and the rest of the country; their backlogs of people who would like to move to the capital are likely in the millions, possibly the high millions. Such massive construction is beyond the pale of political reality: the current high-income resident population is simply not going to allow it – when forced to share a building with the working class, it pushes for poor doors, so why would it want zoning that would reduce the market-rate rent to what the working class would afford? The only political possibility in the short run is partial plans, but these are not going to be of partial use to the working class, but of no use to it, benefiting the middle class instead. As a result, there is no push by the working class and its social democratic political organs to liberalize construction, nor by the small-is-beautiful green movement.
Ultimately, the attempt to bypass restrictions on urban CBD formation by building edge cities, like every other kludge, is doomed to failure. The fundamental problem of rich people making it illegal to build housing nearby is not solved, and is often made even worse. The commutes get worse, and the inequality in commutes between the rich and the poor grows. Office space gets built, where otherwise it would spread along a larger share of the medium-rise CBD, but for most workers, this is not an improvement, and the environmental effects of more driving have negative consequences globally. And once city center is abandoned to the rich, there is no significant political force that can rectify the situation. What seems like a workaround and an acceptable compromise only makes the situation worse.
Freeways are, in principle, much safer than roads with at-grade crossings. With postwar design standards, they eliminate the frictions that are responsible to a vast majority of accidents: grade crossings, left turns, opposite traffic (since they have medians by design), and so on. They also maintain higher design speeds and capacity than less safe local streets. But a more interesting question for policy purposes than “are freeways safer?” is “does the construction of freeways increase road safety?”
For some evidence that the answer is no, see PDF-page 3 of a John Adams paper from 1987 arguing for the continued primacy of Smeed’s Law. Traffic deaths per unit of vehicle distance driven had declined in both the US and UK at a rate following a multi-decade log-linear trend: 3.3% per year in the US, 4.7% in the UK. Regardless of whether Adams’ theory is correct, we can compare actual death rates to the trendline to see what happened. In the US, where the data goes farther back, the greatest period of freeway construction started in the mid-1950s and ended in about 1970; this was also a period in which traffic deaths increased, even more than the trendline based on the explosive growth in driving predicts. Of course the Interstate system also led to traffic growth on at-grade arterials, but the greatest construction growth was in freeways, and on top of this suburban sprawl meant more people would be driving on both the new freeways and the older parkways.
The Smeed’s Law explanation of this is as follows: drivers compensate for the greater safety of freeways by driving more carelessly, on both the freeways and the connecting local roads. The freeways are still safer, but the presence of any safety-improving technology will translate entirely to higher speed and capacity (i.e. drivers keep less distance than they would otherwise), and more careless driving.
There may be other explanations out there – for example, the construction of more roads will cause more dangerous vehicles to start circulating that would not otherwise. These include heavy trucks, and also cars piloted by poor drivers who would not have driven if the construction of an expansive highway had redirected development in such a way that more driving would be needed.
But in either case, what this means is that even though a freeway upgrade of a notoriously unsafe road will make it safer, it will not make the overall road network safer. To argue by analogy with congestion pricing, it is possible that the only way to bend the curve and accelerate the downward trend of vehicle deaths, beyond reducing driving, is to make it more expensive to drive unsafely. For example, insurance requirements could be raised from $25,000 to the rough insurance value of human life in the US, which is in the millions. (The same should be true of any transportation system, but buses and trains are much safer for their passengers than cars.)
The urban geography of transit cities and of car cities is relatively well-understood. In a transit city, there will be a strong CBD surrounded by residences with spiky secondary centers, all quite small geographically but dense, centered around train stations and junctions; because density is high throughout, minor trips are done on foot. In a car city, all trips are done by car, the core is weak, and most employment is in suburban edge cities and edgeless cities.
What I haven’t seen is an explanation of how urban geography works in mixed metro areas: there are those in which short trips are done on foot and long ones in cars, such as new urbanist developments, and those in which short trips are done by car and long ones on transit, such as park-and-ride-oriented commuter suburbs. It is the latter that I want to address in this post.
The first feature of park-and-rides is that of all combinations of modes of transportation, they are the fastest and enable suburbs to sprout the farthest from the center. This is because the segment of the trip done in a car is uncongested and so driving is faster than transit, while the segment done on a train parallels a congested road, and conversely makes few stops so that average speeds are high.
On top of this, because intra-suburban trips are done by car, the density in the suburbs is very low, comparable to proper car cities (see the lower end of the density profiles of the New York, Chicago, and Boston metro areas), and this forces sprawl to go outward. New York is the world’s most sprawling city measured in total built-up area; the only other city of comparable size that’s not a transit city or a bus/jitney city is Los Angeles, which is forced to have denser suburbs because of the mountains. Of course Houston and Dallas sprawl even more relative to size, but because they lack New York’s transit-oriented core, there’s an inherent limit to their size.
The other feature is that there’s a definite socioeconomic history to the development of the auto-oriented commuter suburbs of transit cities. First, people move to the suburbs and commute into the city, almost always by train due to road congestion (or, as in the earliest New York suburbs, because mass motorization hasn’t arrived yet). The mass exodus into these suburbs comes from cars rather than commuter rail, and so the local services for people living in those suburbs are built at automobile scale, rather than at the walkable town center scale of 1910.
In North America there’s also a definite class element here – the early movers are the rich rather than the poor. Historically this was partly because poor people couldn’t afford regular train fare, and partly because the impetus for suburbanization was idyllic country homes with access to urban jobs rather than cheap housing for the poor. If I’m not mistaken, this wasn’t the case in Australian cities’ suburbanization, leading to a more urban transit-style mode of running mainline rail. The result of this class distinction is that North American commuter rail styles itself as for the rich: agencies make an effort to ensure everyone has a seat and downplay comfortable standing space, and the expectation is that transit is a last-ditch mode of transportation for when cars just don’t have the capacity to get people downtown, and so nobody needs to take the trains in the off-peak or take a bus to the train.
The result is that the park-and-ride city will still have a strong core with high-capacity transportation, and the primary CBD will maintain its supremacy for high-income jobs. Establishing edge cities in the direction of the favored quarter can happen, but there’s still a congested city nearby, and so from many directions it’s impossible to drive, and taking transit is impossible. Thus jobs in White Plains and Stamford are not nearly as high-paying as jobs in Manhattan.
There can even be secondary CBDs, if the inner part of the metro area, where people take transit more regularly than the suburban commuters do, is large enough. But those secondary CBDs are frequently quite auto-oriented. Brooklyn’s mode share for jobs is only 42-39 in favor of transit (for residents, it’s 60-25), and all other counties in the New York region except Manhattan have more workers driving than taking transit, a situation that is not true if one looks at residents. Those secondary CBDs then have mixed characteristics: they are dense and fairly walkable, as can be expected based on their history and location, but also have plentiful parking and a large share of drivers demanding even more. They can accommodate multiple modes of transportation, but driving is more convenient, and from the suburbs the commuter rail system isn’t always geared to serve them.
One third of the MBTA’s outstanding debt, about $1.7 billion, comes from transit projects built by the state as part of a court-imposed mitigation for extra Big Dig traffic; interest on this debt is about two-thirds the agency’s total present deficit. Metra was prepared to pay for a project to rebuild rail bridges that would increase clearance below for trucks and cut the right-of-way’s width from three to two tracks. Rhode Island is spending $336 million on extending the Providence Line to Wickford Junction, with most of the money going toward building parking garages at the two new stations; Wickford Junction, in a county whose number of Boston-bound commuters is 170, is getting 1,200 parking spaces.
Supporters of transportation alternatives talk about the inequity between highway and transit funding in the US, but what they’re missing is that the transit funding bucket includes a lot of things that are manifestly not about transit. At their best, they are parking lots and other development schemes adjacent to train stations, which would’ve been cheap by themselves. At their worst, they are straight highway projects, benefiting road users only.
The situation in Boston, while unique in its brazenness, is not unique in concept. In the US, where there are no pollution taxes on fuel, the only way to mitigate air pollution is by regulation and by building alternatives simultaneously. Put another way, combined highway and transit construction is in most cases not really a combined project; it’s a highway project, plus required mitigation. Requiring the transit agency to shoulder the debt and the operating subsidies is exactly requiring transit users to pay for highways. It’s equivalent to charging transit multiple dollars per gallon of gas saved from any mode shift. And it may get even worse: the proposed House transportation bill includes a provision to allow spending national air pollution control funds on regular highway widening, in addition to the current practice of spending them on carpool lanes.
Historically, the diversion of funding from transit to roads took such insidious forms. For an instructive example from Owen Gutfreund’s book, roads advocates fought to get driver’s license fees and even inspection fees for fuel trucks recognized as road user fees, whose proceeds must be diverted toward roads. For another example from the same book, in Denver, the streetcar system was required to cover 25% of the cost of road maintenance on one-way streets and 50% on two-way streets, and as car traffic rose, streetcars both became slower and had to send over more money toward roads.
Another instructive case study is grade separations. It is to my knowledge universal that expressways and high-speed railroads, both of which must be grade-separated, pay for their own grade separations. In all other cases, who pays is determined by which mode is more powerful, and in the US, this is roads. As the national highway system was built in the 1920s, interurban railroads were required to pay for grade-separations, even when the rail came first. The practice continues today: in Kentucky, the railroad has to shoulder the full cost if it’s from 1926 or newer (Statute 177.110), and half the construction cost and the full planning cost if it’s older (177.170). In contrast, in Japan, grade separations are considered primarily a road project, and so the Chuo Line track elevation project was paid 85% by the national and city governments and only 15% by JR East (page 36). The segment in question of the Chuo Line was built in 1889; I believe, but do not know, that new rail construction in Japan is always grade-separated, at the railroad’s expense.
The situation in the US today is a surreptitious underfunding of transit, and at the same time a surreptitious overfunding of roads. It is not subject to democratic debate or even to the usual lobbyist funding formulas, but, like the obscure regulations that impede good passenger rail, hidden in rules nobody thinks to question. To pay for road mitigations and for parking, transit agencies will cut weekend service and reduce frequency. It’s bad enough when done in the open, but it’s done while claiming that transit is too expensive to provide.
In her book Dark Age Ahead, Jane Jacobs complains that freeways as built are good at getting people to macrodestinations (downtown) but not microdestinations (particular addresses within city center). In her example from Toronto, this is correct, but in general, each mode of transportation will be good at serving microdestinations in an urban form that’s suited for it. Cars are not good at serving an intact city center; but equally, transit is not good at serving suburban sprawl, and regional rail that’s not integrated with urban transit is not good at serving urban destinations away from immediate train stations.
The idealized job center in an auto-oriented city is the edgeless city. Even the edge city, as explained in Lang and LeFurgy’s now-paywalled article Edgeless Cities, is too dense, and becomes congested too quickly; indeed, Tysons Corner is infamous for its lunchtime rush hour conditions. Ideally, cars drive from low-density residences to low-density office parks, primarily on freeways but with fast arterial connections at both ends; the freeway network in the auto-oriented city serves an everywhere-to-everywhere set of origins and destinations.
In such an environment, transit can’t do well. The distance between suburban attractors is too great for an easy walk, and the roads are too wide and fast for a pleasant walk. Buses and trains can serve a general macrodestination (“Warwick Mall/CCRI”), but not individual microdestinations, not without splitting and cutting frequency to each destination or detouring and raising travel time. The buses serving Warwick Mall and CCRI have hourly frequency, and are a long, uncomfortable walk from the hotel in Warwick I needed to go to. Judging by the frequency, I’m not the only person who chose not to use them, and take a taxi instead; everyone who has a car or who isn’t extremely price-sensitive does. The only way transit can serve such a destination is by concentrating development near the station – in other words, making a mini-transit city in the sea of sprawl, which generally conflicts with the goal of easy station parking.
In a city, the opposite situation exists. It’s easy to just pronounce transit more suited to dense city centers than driving, but the situation is more complicated. Transit, too, thrives on good connections to microdestinations. It can’t serve employment that’s dense but evenly dispersed in a large area – people would need too many transfers, and the result would be service that’s on paper rapid and in reality too slow. Instead, it works best when all destinations are clustered together, in an area not many subway stations in radius.
In this view, one failure of urban renewal is its failure to recognize that most people who visit city centers are going to do a lot of walking, and amenities should make it easier rather than harder. Traditional urban renewal would build cultural centers and other projects at the fringe of the CBD, to help its growth: Lincoln Center just north of Midtown, Civic Center just southwest of the San Francisco CBD, Providence Place and Providence Station just north of Downcity. In New York and San Francisco, there’s at least rapid transit serving those destinations, mitigating the effects. In Providence, no such thing exists. It’s an inconvenient walk from Kennedy Plaza to the mall and the train station – it’s not too long, but it crosses Memorial Boulevard right when it turns into a freeway on-ramp. Walking to the Westin, immediately adjacent to the mall, is practically impossible without rushing across roads without crosswalks. Even the walk between the station and the mall, which were built together and are close to each other, is much worse on the street than on a map, again involving crossing auto-centric roads.
Organic city amenities do not look like this. If they cluster at the same location (for example, 125th Street in New York, or Thayer Street in Providence), they tend to be along roads that facilitate rather than hindering pedestrian movement. And if they don’t, they are all located along a rapid transit network in its shared service area, where it is still a tight mesh rather than a network of radial lines.
In view of the recent emphasis on parking policy, due to Donald Shoup but now mirrored by other urban planning and transportation experts, the observation is that in any city center, on-site parking is difficult to find. Even in cities that make downtown parking relatively easy to get to, people can’t hope to park at every single microdestination, so instead they trip-chain, driving into the city and parking but going to multiple points within the city, all within a short and easy walking distance from one another. This is roughly the urban geography of the French Riviera, which combines easy parking with a dense, lively center in Nice and a fair amount of urbanity on some streets even in auto-oriented secondary cities such as Monaco and Menton.
The connection to regional rail is that, historically, it descends from intercity trains, and therefore the conception of connecting the suburbs to the city is very macrodestination-driven. To name two egregious American examples, the Boston’s north side lines and Caltrain both connect many suburbs to the city while also connecting people to the suburban tech job corridor, but in reality miss the biggest job centers at both ends. North Station is two subway stations north of the CBD, and as a result ridership underperforms the south side lines; 4th and King is far enough outside the Market Street CBD that it’s not close to the CBD jobs – the proposed Transbay Center site, which is, is located near more jobs than all existing Caltrain stations combined. And if microdestination-level service to an already transit-oriented CBD is bad, then service to other urban destinations is worse: urban station spacing is wide, there’s no attempt to develop near stations, and the poor integration with local urban transit ensures that even people who could be willing to make the last-mile transfer don’t.
Gendered Innovations’ charts of trip chaining and gender breakdown of public transit riders got me thinking about how different systems of transportation handle a mixture of short and long trips. Eric Jaffe at The Atlantic Cities reports this and suggests that transit agencies orient physical features such as accessibility to the needs of women who trip-chain care and work trips.
But to me, the first observation is that although women trip-chain more, it doesn’t seem to be true that women are more likely to ride transit in the US than men just because of trip-chaining features. Instead, women traditionally have been less likely to have jobs requiring commuting, and the commute gap has been shrinking more slowly than the gap in employment.
This comes from the fact that trip chaining on transit is cumbersome in most cases. Both cars and transit have to deal with the time it takes to stop for an errand, but transit tends to handle this worse, unless it’s very frequent and has practically zero access and egress times. Transit cities instead get people to take their short errand trips on foot – since their neighborhoods are denser and have more mixtures of uses, they make retail and care trips attractive on foot. In light of the fact that walking is not useful for long commute trips and transit is not useful for short errands, we can construct the following typology of cities:
|Long \ Short mode||Foot, bicycle||Car|
|Car||New urbanist, small-town, auto-oriented dense||Auto-oriented|
Auto-oriented cities are the easiest: in those places, people drive for all purposes. Trip chaining can be done on a commercial arterial road, dropping off laundry or kids or buying something on the way to work, and because of ample parking availability, the time each additional link in the chain consumes is very small, since the longest access and egress time comes from navigating from the residential cul-de-sac to the arterial and from the arterial to the office park.
Traditional suburbs, common around New York and Chicago and sometimes in other old North American cities, are similar for trip-chaining purposes. In those areas, the urban form is suburban and auto-oriented, but work trips to the city are done by commuter rail or occasionally commuter bus, since the city is not as auto-friendly as the suburbs.
Transit cities too have their long-range commuter rail, but it is built as an extension of walking rather than of driving. Neighborhoods tend to have mixed uses, and there’s a concentration of retail development near the outlying stations, sometimes forming large secondary clusters but sometimes just acting as neighborhood centers. It could take considerable time to add more trips to one chain, especially if not everything is located at the train station. But conversely, the amount of time a single short trip takes is small, unlike the case for auto-oriented cities – the supermarket is right around the corner, and within five minutes’ walk are plenty of stores. When people walk, the concept of a single trip begins to lose meaning then. Potentially, every single purchase can be considered a separate trip, in which case the chaining becomes quite long.
In many places the transit is absent and people drive outside the neighborhood, while still doing errand trips on foot. This is the typology that characterizes different environments including new urbanism, traditional cities like Providence and Tel Aviv that have been made car-oriented, and auto-oriented modernist projects such as Co-op City. Those environments all differ in how trip chaining is done. In principle, it can be done on foot, but usually people who can drive do.
If my own experience is any indication, one feature of cities in this typology is that children and teenagers walk more. In Tel Aviv, my father drove me to elementary school on the way to work while (in later grades) I walked back, and I took the bus to and from middle school. Most trips my parents did in a car, but there was a reasonable number that were short enough to walk. I’d walk to farther destinations such as the cinema and the urban mall. The view of the North Tel Aviv middle and upper-middle class of the 1990s as I remember it is that the bus is fine for trips to school, but adults drive. I doubt I’d have had the same view if I’d grown up in New York, or for that matter in the Houston suburbs, where everyone drives or is driven.
Although most of the discussion about transit cities contrasts them with car-oriented cities, the other two typologies need to be examined, too. When adults and children trip-chain differently, children can get a distorted view of who transit is for (poor people, people who can’t drive yet), and the next generation will make the city auto-oriented; this is indeed what is happening in Tel Aviv, which despite population growth in the core is adding cars and spawning low-density suburbanization well outside the built-up urban areas.
Likewise, Cap’n Transit’s attacks on park-and-rides don’t quite capture what is wrong with the car/transit typology. A transit agency that wants to make it easier to trip-chain will want to concentrate development near the train stations, because that’s where it’s easiest to add minor trips without having to walk ten minutes out of one’s way. Of course in the middle of the dense city there’s development everywhere, which may well be orthogonal to where the subway is, but then trip-chaining becomes easier because each foot trip is so short.
The principle is that cars are a big one-time purchase but have a much lower marginal cost of usage. If one major class of trips can’t be done on transit – and chained trips generally can’t when they require the rider to wait for the next bus and the next bus will come in 15 minutes – then people will buy a car and then drive it even for trips they’d happily take transit to if they didn’t already own a car. The class of trips that can only be done conveniently by car needs to be kept small enough that people will use car share, take a taxi, or beg a friend who does own a car.
Thus what transit agencies and pro-transit politicians should devote more time to is appropriate development more than physical features of the transit system. Accessibility is important for so many reasons other than strollers. In contrast, the primary importance of using transit to extend the range of the pedestrian rather than provide a capacity boost for the car is precisely that transit needs minor trips to be doable on foot. A transit system that one needs to take to the supermarket may be technically successful, but it’s in a failed urban area.
Cap’n Transit is virtually alone in the transit blogosphere in opposing the Tappan Zee Bridge widening and replacement. Unfortunately, merely opposing a highway project, expensive as it is, is not enough; as we’ve seen in the failure of the ballot proposition to ban a highway tunnel in Seattle, opponents of highway expansion need to make it concrete and clear what transit alternatives there are. In the case of the Tappan Zee specifically, alternatives exist, but serve different markets, and it’s necessary to explain why the market that the Tappan Zee serves is not the most important to the region.
I propose a regional rail system instead, focusing on serving Rockland County and perhaps a few centers in Orange County. There are multiple lines crisscrossing Rockland County, with limited or no freight traffic, passing through old town centers that would make good regional rail stops and connecting to good alignments in North Jersey. For a regionwide perspective there are my original regional rail proposal and my more recent focus on connectivity from North Jersey to Lower Manhattan, but the important thing for the purposes of Rockland County is the question of which lines could be used. The Erie Main Line only goes to Suffern, but could collect passengers from the western parts of Orange County; the Northern Branch, including an abandoned northern end, goes as far north as Nyack; the Pascack Valley Line was abandoned north of Spring Valley but has an intact right-of-way as far north as Haverstraw; the West Shore Line goes north to Albany and has moderate freight traffic, easily accommodated in the off-peak if double-tracking is restored. There are so many options that the main question is which to activate just to maintain adequate frequency.
The main difference with any Tappan Zee proposal is that the existing rail lines go north-south, whereas the Tappan Zee is east-west. Fortunately, most existing movement is north-south. As can be confirmed by the 2000 census, Rockland and Orange Counties’ commute market toward Westchester and other suburbs accessed by the bridge is quite small: 18,000 to Westchester and Fairfield. The volume of commuters from those two counties to Bergen and Passaic Counties is somewhat larger (22,000), and that to New York City more so (27,000 to Manhattan, 14,000 to the other boroughs). And traffic over the bridge since 2000 has stalled.
Not only is the north-south or northwest-southeast market bigger than the east-west market, but also it uses the Tappan Zee when it could be diverted if there were alternatives. A breakdown of travel on the bridge reveals that 16% of eastbound travel is to the Bronx and another 15% is to the other four boroughs and Long Island; this could be done competitively by various transit options.
Thus, a transit option that emphasizes north-south connectivity and goes to Manhattan through Bergen and Passaic Counties is going to serve more people than adding more east-west connectivity. It could serve far more if North Jersey jobs clustered in Paterson, Hackensack, and other old city centers, but in fact they’re diffuse. It’s unreasonable to assume significant commercial transit-oriented development in North Jersey, though a few jobs in Paterson could still be captured; however, jobs in Manhattan, Brooklyn, and Queens could be served well.
Finally, to serve Bronx and Upper Manhattan jobs from both North Jersey and Rockland County, the trains should be combined with good bus service across the GWB. For example, bus lanes on Route 4 could be a strong start, especially if the trains are timed to connect to the buses. More speculatively, there’s a subway bellmouth allowing an extension of the C along the GWB, and relative to the cost of tunneling it should be inexpensive to extend the C as an elevated line toward Paterson over Route 4; the drawback is that the C is slow and would poorly serve the Bronx.
Although Rockland County is very sprawling, it has just enough old cities to anchor regional rail at the residential end. The effect is magnified if we can assume some TOD – for example, developing over the many parking lots currently in place in Nyack near the legacy Erie station – but as with commercial TOD, this is desirable but not very likely with the current political structure. Fortunately, American commuter rail works very well as a shuttle that extends auto-dependent commutes into cities that have no room for more cars; as a narrow alternative to constrained highways, it often succeeds, and would be a no-brainer compared to a bridge as expensive as the Tappan Zee.
The cost of reviving and electrifying the four lines proposed in my regional rail post (Erie Main, Pascack Valley, West Shore, and Northern Branch) is quite small compared to either the cost of bringing them to Manhattan or that of rebuilding the Tappan Zee Bridge. The cost of bringing the lines to Manhattan is substantial, but done right it would be much lower than the Tappan Zee Bridge’s $8.3 billion excluding any transit component.
If costs could be brought down, a new crossing, slightly farther north of the existing bridge, could work well for rail. The transit mode selection report discusses commuter rail on the new bridge, and the concept would be similar except that there should be more stations to serve local traffic better. A rail-only bridge would leave the Hudson Line north of Tarrytown, allowing west-of-Hudson commuters to access this job center and also ensuring no loss of frequency to the station, and then cross to Nyack. It would have to be underground in Nyack because the Palisades rise too steeply from the water, and would surface just west of the urban area. If all trains serving the line are EMUs, rather than diesels or even dual-mode locomotives, then the grade could be sharp enough to limit tunneling to the urban area of Nyack; the TMS report, which only considers diesels, proposes 2 miles (3.2 km) of tunneling, but EMUs climbing 4% grades could cut this by more than half.
The advantage of the east-west option is that it would serve Westchester jobs; while the commute market from Rockland and Orange Counties to Westchester is as mentioned not large, it clusters along I-287, especially in White Plains, and is thus somewhat more rail-serviceable. In addition, although the chance of commercial TOD is small everywhere in the US, it is larger in Tarrytown and White Plains than in Paterson and Hackensack.
On the other hand, if the costs could be brought down, they would be lower for everything, including highways. The same factors that cause transit construction costs to be so high in New York (namely, overstaffing, and poor contracting practices) apply to highways equally. In particular, the decision about what mode to favor should only weakly depend on cost, since relative costs both within transit modes and between cars and transit are not too different from in lower-cost countries.
To cut costs to a minimum while still providing acceptable first-phase service, the initial network could include only the lines that could be brought to Secaucus, with some track modifications near the station allowing Erie trains to terminate at the station parallel to the Northeast Corridor tracks; this still involves a fair amount of concrete pouring, but much less than a new tunnel to Manhattan, and the transfer could be made as convenient as that at Jamaica. In addition, trains could be mixed and matched: that is, to let a few of the Erie trains serve Manhattan directly, some Northeast Corridor or Morris and Essex trains could be cut to Secaucus. The main disadvantage is that no such option is possible with the West Shore Line and Northern Branch, and so it would be more useful in the western part of Rockland County than in the eastern part.
The selling point of the regional rail alternative is that, despite job sprawl, Rockland County residents are still more likely to need to travel to Manhattan than to Westchester. Thus, the promise of a one-seat ride to Manhattan on frequent train service, or at least a two-seat ride with the same quality of transfer offered to Long Islanders, could carry some political weight. One does not drive into New York out of love of driving; one drives into New York out of necessity, and making this less necessary could reduce some of the political will to spend billions more than required on widening a bridge.