Tag Archives: networks

HSR and Air Travel – partners and competitors

Alon Levy wrote about the USDOT’s airfare database and the implications for potential high speed rail markets. Alon’s broad conclusions are that the regional markets suitable for HSR haven’t changed all that much in the last decade – the NEC is the most promising corridor, California is second, and others also make sense – but short of a true national network.

His post sparked me to ask – what are the best practices for integrating HSR with airports? High Speed Rail networks have different characteristics from airline networks. Some elements of the services are competitive, while others are complementary. A big part of the political sell for HSR in California was the counterfactual of required airport investment to facilitate travel in the state – but what’s the real impact on airports and airline service?

HSR Corridors vs Airline Hub Networks

Even modest rail systems can effectively compete against air travel in given corridors. Amtrak often brags about the barely-high-speed Acela earning an 80% share of the air/rail market (a notably smaller portion of the overall travel market) between NYC and DC. American and Delta still offer their Shuttle flights between DCA and LGA, but they don’t dominate they way they used to.

Amtrak has the advantage along a linear corridor, where one train making multiple stops serves multiple markets – If United Airlines wanted to match service along the NEC, they’d need a lot of feeder flights from DCA, BWI, and PHL into EWR – and they’d have to run them far more frequently to offer as many departure times.

Airline hubs are a different beast – the spokes all feed traffic into the hub. They’re not flying a route solely for the local traffic, they’re also feeding traffic into their hub to connect to other routes.

International Comparisons

Despite the track record for HSR in other countries, there are surprisingly few examples of excellent air-rail integration. Only a handful of big airports have quality connections to HSR networks: Frankfurt, Paris-CDG, and Amsterdam are most prominent. I found this paper exploring the history of both FRA and CDG:

In Frankfurt, the addition of HSR service allowed Lufthansa to decrease domestic flights and increase international flights without losing domestic passenger feed:

With the opening of the Frankfurt–Cologne and Frankfurt–Stuttgart HSR lines, Frankfurt Airport increased its catchment area by 10 million people who suddenly lived within 2 h of the airport…
Whereas Frankfurt Airport may be limited in terms of capacity, it has managed to support an increase in international passenger traffic and to maintain dominance in Germany as the major long-haul international airport serving the country.

Conversely, at CDG, Air France retained a small number of domestic flights to feed their long-haul flights, despite the TGV’s dominance in markets to/from Paris:

The other two routes, Paris–Lyon and Paris–Montpellier, experienced a relatively flat trend in passenger traffic, although there are competitive HSR alternatives that link these cities directly to CDG. In particular, the capacity on these routes has remained relatively stable, supporting research claims that airlines are likely to maintain a certain number of flights at their hub airports to maintain their network, even with the presence of fast and reliable HSR–air connectivity (7).

The paper’s conclusions about the characteristics of a successful HSR/airport integration:

Infrastructure. To provide feeder or transfer service between HSR and air transportation, the rail station should be located at the airport. If the HSR connection at the airport is constructed as a detour from the primary network patterns on the rail system, it is unlikely that the airport will be served with enough frequency.
Schedule and frequency. Rail operators and airlines often have the same goal of optimizing their networks, but they are separate networks. Coordinating timetables to ensure that rail service meets banks of connecting flights is an important consideration.
Market characteristics of the airport. In the two successful cases in this study, the primary airports with HSR links were the dominant international hubs of each country. For both CDG and Frankfurt International Airport, domestic traffic declined and international passenger traffic increased. Two key factors may have influenced this growth: partial alleviation of congestion at the airport by decreasing domestic flights and success of the HSR lines as feeder service for international flights.

In other words: lots of similar patterns to good transit planning on the rail side of the equation: Be on the way; frequency is freedom, etc. The key difference is about integration: is HSR service best thought of as a means of ground transportation – just extending an airport’s catchment area? Or is it best considered like a true connecting flight – integrated into an airline’s ticketing, loyalty programs, baggage handling, etc.

For airports and airlines, things are a bit more complicated. Both CDG and FRA are huge hubs, and the primary international connecting hubs for their respective countries.

In the US, the airport/airline situation is quite different. As a much larger country, no airline operates a single hub that dominates international traffic the way that CDG and FRA do in France and Germany. Far more medium-distance air travel is domestic travel; US visa rules and unfavorable geography make international-to-international connections less common – meaning domestic feed at big connecting hubs is even more important.

Future US HSR/Airport Links

Alon’s conclusions:

In the Midwest, the core lines remain strong, but more peripheral Midwestern lines, say a bypass around Chicago for cross-regional traffic or improved rail service due west toward Iowa, are probably no longer worth it. The Cleveland-Columbus-Cincinnati corridor may not be worth it to build as full HSR – instead it may be downgraded to an electrified passenger-primary corridor (as I understand it it already has very little freight).

Now, Alon was using this air travel data as a proxy for overall travel demand. Assuming the demand is still there (even if the recent growth has been mdoest) Chicago strikes me as a market with great potential as an air/rail hub – a huge hub airport, located near existing candidate HSR lines, and wouldn’t require a large detour to serve. The full Midwest HSR network centered on Chicago could extend ORD’s catchment area (connecting MSP, MSN, MKE, DTW, STL, CLE, and others) and potentially free up airport capacity for longer-haul, higher-value flying.

SFO is another airport that stands to benefit from HSR. SFO’s airfield is constrained and unable to expand; United’s trans-pacific hub depends on feeder flights often limited by poor visibility; the airport’s location is immediately adjacent to the planned HSR service.

Better planning for CAHSR would add even more value to the connection at SFO – particularly had planners used Altamont Pass, the airport would have a faster connection to Sacramento, increasing SFO’s catchment area.

The Northeast Corridor has lots of potential air-rail connections. The rail line itself passes plausibly close to lots of major airports: DCA, BWI, PHL, and EWR. DCA lacks international flights and is can’t grow; BWI’s hub carrier is almost entirely domestic and doesn’t have many international flights to feed.

Both PHL and EWR are interesting candidates for American and United, respectively. Newark in particular meets all of the criteria for success described in the paper. United already uses EWR’s proximity to code-share with Amtrak in lieu of flying short connecting flights from Philadelphia (though the business practices of Amtrak and United are quite different and can make for a challenging passenger experience) and United recently announced cutbacks to flights within the NEC to EWR – dropping the 4x daily BWI-EWR service due to airport constraints.

Philadelphia would require an airport station along the NEC that doesn’t currently exist. The airport’s proximity to New York and the larger travel market there means a bit of a precarious existence, but PHL’s hub carrier (American) has recently been shifting connecting traffic to PHL and away from their greater New York operations, which are split across LGA and JFK and increasingly focused on serving local traffic.

The potential is there for these airports – the big questions will be a) if HSR service ever exists (or improves), and b) what form the airline/railroad partnership takes – as a true connection, or as extended ground transportation?

Dispatch from the battle lines over Globalization: US Airlines take on the Middle East Carriers

Dubai International Airport. CC image from Raihan S.R. Bakhsh

There’s a fight brewing amongst big international airlines. The old guys are complaining that the new kids aren’t playing by the same rules; the new kids argue that the old guys need to step up their game. The dispute represents a fascinating window into a very public battle over globalization. What are the rules, and who gets to make them?

A coalition of the three major American airlines (American/US Airways, United, and Delta) combined with many of the unions that represent their employees are putting on a full-court press (complete with ads in DC’s Metro), arguing that the Big Three carriers in the Middle East (Emirates, Qatar, and Etihad – often abbreviated as the ME3) are undermining the principles of free and fair competition with subsidies that distort the market. The Gulf air carriers are pushing back against the accusations, arguing they provide a superior product at a lower cost. Vox has a brief article that summarizes the arguments for both sides.

The US carriers outline billions in subsidies to these carriers. They include everything from subsidized development of the region’s massive airports to interest-free loans and infusions of capital from the ruling families – who also own the airlines themselves. The alleged subsidies support Qatar and Etihad to a greater degree than Emirates (the paper alleges that Qatar and Etihad would not be viable commercial businesses without their subsidies; not so for Emirates). You can find the white paper and presentation here.

Summary of the subsidies alleged by the US carriers. Image from the Americans for Fair Skies presentation.

Central to the debate are the United States’ Open Skies treaties with Qatar and the United Arab Emirates. Open Skies treaties deregulate the routes and destinations for international air travel between the two signatories. The US State Department prioritized signing Open Skies agreements since signing the first such agreement between the US and the Netherlands in 1992 (see the full list of agreements here, as well as the text of a sample agreement).

There is an inherent asymmetry in any Open Skies agreement between the United States and Qatar or the UAE; due to the small size of those countries, the agreements only add two or three destinations worth serving for US airlines (indeed, there are only two scheduled flights to Qatar or the UAE from US-based carriers – Delta flies ATL-DXB and United flies IAD-DXB). Gulf airlines, however, earn rights to fly to a wide array of American cities.

Part of the success of the Gulf carriers is due to the geographic advantage of the Middle East hubs. Dubai has long served as a stopover point for refueling along the Kangaroo Route. Now, carriers like Emirates use Dubai as centrally located hub to efficiently connect air traffic between Europe, Africa, India, and Southeast Asia.

However, there’s more to the rise of the Gulf carriers than advantageous geography. For these Gulf states (often, effectively, city-states), focusing on aviation is a deliberate economic development strategy. When you’re talking about state-owned businesses, how do you differentiate between the viability of the various airlines as businesses from the state’s explicit policy of aviation-focused economic development? In their white paper, the US carriers make the case that Open Skies agreements assumed that an open market would provide a superior business model to state-owned airlines (and there is a long history around the world of poorly run state-owned airlines) and that competition would bring this truth to light. However, with the rise of State Capitalism, the US carriers argue, it’s not clear that assumption can be trusted.

It’s the next step in the idea of developing around the aerotropolis. Instead of building your economy around an airport, why not build it around an airline? Dubai’s success in developing their middle-eastern metropolis around a global aviation hub inspired Qatar and Abu Dhabi to do the same – a strategy that not only required the airport, but the airline to feed it.

The Gulf carriers aren’t just looking to their Middle East hub airports, either. Emirates took advantage of struggling Alitalia to earn a fifth-freedom route from Milan to JFK. Emirates makes no secret of their ambitions to offer service around the globe via some key fifth-freedom routes:

President Tim Clark has revealed the first details of what looks like the next step in Emirates’ march to become a truly global powerhouse. On the sidelines of last week’s International Air Transport Association (IATA) annual general meeting in Cape Town, the airline outlined plans to set up a major transpacific operation. Its aircraft would be flying through intermediate points in Asia to destinations in North America. What is making the threat even more serious for Asian and U.S. airlines is that Emirates has another 67 Airbus A380s on firm order, which—like its large incoming fleet of Boeing 777-300ERs—has the range capability to fly from many points in Asia to cities far beyond the U.S. West Coast.

Emirates can choose from several geographic points that offer the necessary aeropolitical framework. The United Arab Emirates (UAE) has an open skies agreement with the U.S. “It allows us to take passengers on a fifth-freedom basis from the West Coast and central points in the U.S. to points in Asia,” Clark says. In Asia, there are open skies agreements with Thailand and Singapore. Emirates also has similar rights for some destinations in Japan.

Bold added. This is the root of the entire debate: a battle over the details of a global aeropolitical framework. A battle over the rules.

When it comes to Emirates, their Dubai hub isn’t the concern from the US carriers. The real concern is these aspirations to cover the globe with fifth-freedom traffic. Delta claims that the ME3’s cheap connections in Dubai make it difficult to serve India directly from the US (and presents strong competition for the European joint venture partners if connecting to India in Europe). Flying to US cities from Europe or Asia directly (e.g. the current New York-Milan service, if expanded to other airports) threatens to undermine direct service to Europe; additional fifth-freedom routes across the Pacific could do the same. Brett Snyder notes the concern about hurting the overall network:

If the Middle East carriers skim the international markets with the most traffic, then the US carriers will have to cut back service. When international flights get cut, the whole network becomes vulnerable. The end result is probably less service for smaller and mid-tier cities. It’s just the way the network effect works.

While the American carriers are asking the US Government to revisit these agreements, the Feds must balance other US interests in the region beyond air travel. Qatar and the UAE host a number of US military facilities. The US has a large trade surplus with both nations, partly due to companies like Boeing selling lots of widebody airliners to the Gulf Carriers. American cargo airlines like FedEx take advantage of Open Skies in a similar fashion to the Gulf carriers, facilitating global cargo movement. In other words, it’s not clear the US carriers have a sympathetic ear from the Federal government.

The PR campaign from the US carriers is an attempt to change policy by influencing public opinion, but it will be an uphill climb with the general public. Counter-arguments from the Gulf carriers ask why the American carriers are afraid of competition. US airlines aren’t exactly earning lots of sympathy from the public.

The PR battle is also getting nasty: Qatar Airways’ CEO accuses Delta of flying “crap” planes without a hint of irony: it’s not hard to buy nice, new aircraft when you can fall back on massive capital infusions (as alleged in the white paper) to buy those expensive aircraft. Lufthansa’s CEO, facing a strike from his unionized pilots, joked that he should hire Qatar’s CEO as his union advisor (unions being illegal in Qatar and the UAE). And while customers might like the product and the price point offered by the Gulf carriers, it’s not clear than anyone in the US would be willing to accept the trade-offs that make that product possible.

The white paper notes that the subsidies documented meet the World Trade Organization definition. However, even though both Qatar and the UAE are part of the WTO, aviation isn’t a core part of the WTO’s agreements.

If aviation were a part of the WTO, there would be a specific process to raise and resolve disputes. In other trade areas, the WTO can authorize the use of ‘counterveiling measures’ against subsidies and dumping, such as tariffs or restrictions on trade volume. But here, there aren’t any specific rules governing aviation – hence the PR campaign.

In essence, this is a battle over the rules. If the story of the aerotropolis is the story of globalization, is this a tide that lifts all boats? Or is it a race to the bottom? Competition is good, but what if the basis for that competition is based on the rules governing labor markets in Qatar or the UAE? Will the fight over the rules of the game lead to improvements in working conditions for migrant labor in the middle east? While the US airlines are certainly acting in their own self-interest, is this battle similar to the public scrutiny over Qatar’s labor practices in advance of hosting the 2022 World Cup? Could this battle over the rules not only find room for fair competition, but also leverage an improved quality of life elsewhere in the world?

Or is all of that wishful thinking?

Speed, urban transportation and geometry heuristics

Following up on this previous post, noting that “transport is mostly a real estate problem” – a few quick heuristics on cities, speed, and space:

Comparison of population/employee density and street area per person. Image from NYU Urbanization Project.

Regarding speed:

Speed requires space; faster travel occupies a larger area than slower travel.

Speed alters our perception of space. Faster travel makes large things seem smaller (hat tip to this post from GGW for the links). The properties of the space affect how we use it and what we percieve it to be; wider roadways within streets get used for faster travel.

Regardless of speed, cars require large spaces relative to their capacity. Even when parked (v = 0), cars require lots of space. By extension, building cities around requires a completely different spatial footprint.

Regarding space:

There is a strong tendency for cities to devote about 25% of their land to streets. Street networks are for mobility, but also for access to land. Devoting too much land to streets is wasteful; too little makes it difficult to unlock the value of the land within a city.

Intersection density correlates with walkability and connectivity; wider instersection spacing correlates with the higher speed travel of cars.

Consider the relationship between the density of the network (intersection density), the tendency to use ~25% of land for streets (regardless of the density of the place), and street width on the kind of transportation.

Simply requiring some minimum intersection density for new developments via a code will still be subject to ‘gaming’ and open to unintended consequences.

Street networks are sticky and tend not to change once established; the cities that grow around them are path-dependent. However, transport networks can be layered – subways travel fast, require space and grade-separation, but deliver passengers to the street grid as pedestrians; just as freeways are layered above/below streets and deliver high volumes of cars to local streets.

While the physical space allocated to streets tends not to change, the use of that space can change a great deal over time.

More on the geometry of transportation: “Transport is mostly a real estate problem”

In June, the Urbanization Project at NYU’s Stern Center posted several graphics looking at the space devoted to transportation in our cities. As the author, Alain Bertaud, frames it, “transport is mostly a real estate problem.” That is, different transportation modes require different amounts of space to accomplish the same task.

Comparison of population/employee density and street area per person. Image from NYU Urbanization Project.

Each of the selected examples cluster around the diagonal blue line, representing an average of 25% of a city’s land devoted to streets.

Percent of land use devoted to buildings, streets, etc. Image from NYU Urbanization Project.

Two observations: the 25% pattern is remarkably consistent; as is the geometric relationship between modes of transport and the intensity of land use. The green horizontal lines show how much space a car uses at various speeds – the faster the car goes, the more space it requires. A parked car occupies 14 square meters, while one moving at 30 kph takes up 65 square meters.

The obvious corellation is between a city’s density and its type of transportation network. Cars take up a large amount of space relative to their capacity, and a transport system based on cars alone cannot support a great deal of density.

Alex Tabarrok frames this in terms of “the opportunity cost of streets.” While there is certianly an opportunity cost to various street uses, it’s worth noting that some space must be devoted for streets in order to access property. Charlie Gardner at Old Urbanist takes note that the role of streets is not solely about transportation:

In addition to their transportation function, streets can also be understood as a means of extracting value from underserved parcels of land. The street removes a certain amount of property from tax rolls in exchange for plugging the adjacent land in to the citywide transportation network. Access to the network, in turn, increases the value of the land for almost all uses. For the process to satisfy a cost/benefit analysis, the value added should exceed that lost to the area of the streets plus the cost of maintenance. (This implies rapidly diminishing returns for increasingly wide streets, and helps explain why, in the absence of mandated minimum widths, most streets are made to be fairly narrow.) For many of the gridded American cities of the 19th century, as I’ve written about before, planners failed to meet these objectives, although these decisions have long since been overshadowed by those of their 20th century successors.

Charlie also notes that many great, dense, walkable cities around the world devote about 25% of their land to streets, yet many American downtowns use a much higher percentage of their land to streets.

Some of those numbers might depend on the exact method of accounting. While Charlie’s estimate for downtown DC shows 43% of the land used for streets, DC’s comprehensive plan shows approximately 26% for the city as a whole:

Land Use Distribution in DC, from DC’s 2006 Comprehensive Plan.

The graphic doesn’t specify if the street figure refers to street right of way, or just the carriageway portion of the street, but not the ‘parking area.‘ Seattle’s planning documents also showa similar pattern: 26% of land city-wide used for streets, but also a higher percentage of downtown land devoted to streets.

Seattle land use distribution by neighborhood. Image from Seattle’s 2005 Comprehensive Plan.

The Seattle calculation looks at land devoted to right of way for streets, rather than just impervious surface.

Making better or different use of existing right of way is one thing; however, once that right of way is set, it is very difficult to change. Transportation networks awfully path dependent. Chris Bradford looks at Austin’s post-war planning and the abandonment of the street grid – path dependence in action:

Back then, “planning” chiefly meant “planning streets.” It’s a shame that planning lost that focus. The street grid that permeated Austin in 1940 is of course still with us, and forms the backbone for a number of quite livable neighborhoods.

So what happened? Developers building large, planned subdivisions (Allandale, Barton Hills) continued to add decent street networks after 1940. But the City itself appears to have gotten out of the grid-planning business not long after this map was made…

Collectively, these could and should have been platted into 40 or so city blocks. Instead, they remain two big blobs of land. The lack of connectivity funnels traffic onto South Lamar and Manchaca; impedes east-west mobility, dividing eastern and western neighborhoods; forces people to make circuitous trips to run even simple errands; and forecloses any sort of low-intensity, mixed-use development in the area. Then there’s the sheer loss of public space: South Austin should have a few more miles more of public, connected streets than it has today.

Once the street grid is set, it is very difficult to change.

Cities as complex systems – with scientific research to show it

False-color satellite image of China’s Pearl River Delta. Top image is from 1973, bottom image from 2003. CC images from NASA.

Building off of previous research working towards a universal theory of cities, Luis Bettencourt is back in the news with a new paper (working paper version here) that argues cities are a new kind of network not easily captured by analogies to natural systems. Rather, cities are “part social reactor, part network.”

Based on this theory, Bettencourt identifies the basic patterns of how cities grow. From that observation, Bettencourt builds his theory, allowing for the determination if cities are under or over-performing.

From the Santa Fe Institute’s article on the paper, this theory of cities is described as follows:

o what is a city? Bettencourt thinks the only metaphor that comes close to capturing a city’s function is from stellar physics: “A city is first and foremost a social reactor,” Bettencourt explains. “It works like a star, attracting people and accelerating social interaction and social outputs in a way that is analogous to how stars compress matter and burn brighter and faster the bigger they are.”

This, too, is an analogy though, because the math of cities is very different from that of stars, he says.

Cities are also massive social networks, made not so much of people but more precisely of their contacts and interactions. These social interactions happen, in turn, inside other networks – social, spatial, and infrastructural – which together allow people, things, and information to meet across urban space.

Ultimately, cities achieve something very special as they grow. They balance the creation of larger and denser social webs that encourage people to learn, specialize, and depend on each other in new and deeper ways, with an increase in the extent and quality of infrastructure. Remarkably they do this in such a way that the level of effort each person must make to interact within these growing networks does not need to grow.

The argument that cities can be partially explained with natural analogies sounds similar to the use of the constructal law to explain cities, but Bettencourt is arguing that there is a similar, but different relationship here.

Emily Badger summarizes and explains Bettencourt’s research at Atlantic Cities:

But Bettencourt is basically describing interconnected relationships between the population growth of a city; the incremental expansion of the infrastructure networks that more people require; the socioeconomic outputs that come from our social interaction; and the density that necessarily develops over time so that we can still benefit from ever-more social connections without spending ever-more energy to reach each other.

As cities grow, Bettencourt says, the city comes to you. This is a high-minded way of talking about infill development. If cities continued to grow but only grew outward, you would never get any benefits out of knowing or working with new people, since you’d have to sit in traffic for two hours to reach them. Density, however, allows us to reap the benefits of more social connections without adding too many costs in congestion and energy (like gas). All of this enables the amazing growth and benefits of cities to be open-ended.

Per Square Mile offers a summary as well:

Bettencourt believes there are four sparks that cause cities to form—the mixing of populations, the incremental growth of networks, the bounds of human effort, and the relationship between socioeconomic output and personal interaction. According to these assumptions, cities are founded and grow primarily so that people can interact frequently and on a personal level. As demand for face time swells, cities expand, incrementally adding to the existing network. Eventually, those networks reach a limit, bounded by the amount of effort we are willing to expend to expand and maintain them. The greater the benefit of living in a city, the more effort we’re willing to expend to sustain it. Bettencourt’s final assumption may be his most astute—that cities aren’t just agglomerations of people, but also concentrations of social interactions.

The formulas Bettencourt derived could prove powerful. His most muscular equation, that which models city growth, identifies cities that punch above and below their weights. Others show how substandard transportation can hold a city back, or how transportation networks tend to grow incrementally (perhaps that’s why automobile sprawl seems so intractable). But his formulas also highlight some perils, like how energy loss in transportation increases superlinearly—the more you move, the more energy it takes to move something. In sum, they appear to build a solid theoretical framework by which further questions can be asked and hopefully answered.

Questions immediately come to mind about matching our policies to this theory; what the trade-offs between growth and the benefit of living in cities look like in the real world beyond the theoretical framework. Conversely, how might such a theory influence policy? Could an understanding like this help with proposed policy frameworks such as the zoning budget? What about the qualitative elements of a place and the influence they have on these dense, social networks?

Links: The new American Dream

House for rent. CC image from Sean Dreilinger

Foreclosed sprawl – the next frontier of renting? The New York Times looks at the practice of firms buying up foreclosed, cookie cutter sprawl housing at relatively low prices with the idea of renting these houses out to tenants.

As an inspector for the Waypoint Real Estate Group, Mr. Hladik takes about 20 minutes to walk through each home, noting worn kitchen cabinets or missing roof tiles. The blistering pace is necessary to keep up with Waypoint’s appetite: the company, which has bought about 1,200 homes since 2008 — and is now buying five to seven a day — is an early entrant in a business that some deep-pocketed investors are betting is poised to explode.

With home prices down more than a third from their peak and the market swamped with foreclosures, large investors are salivating at the opportunity to buy perhaps thousands of homes at deep discounts and fill them with tenants. Nobody has ever tried this on such a large scale, and critics worry these new investors could face big challenges managing large portfolios of dispersed rental houses. Typically, landlords tend to be individuals or small firms that own just a handful of homes.

Cities usually have more rentals, and for good reason. Apartments have common structural elements and provide for economies of scale in managing multiple units. Applying this to large-scale single family detached homes is a different and challenging model, but a seemingly inevitable result of the decline in home prices in these areas once built on speculation.

It’s also an example of housing market filtering in action.

This isn’t quite what the concept of filtering is about… Cap’n Transit disputes the concept of filtering, noting that such shifts are not permanent. However, I don’t think anyone was asserting they were. Filtering is a process, a description of the market responding to shifting demand. It is not a description of an end state.

It’s true that most of those buildings were not well-maintained, but the causation is more likely the other way around: the landlords didn’t put a lot of money into them because they didn’t bring in much rent. So why were the rents so cheap? I’m guessing that there were several related factors: racism, city services, crime, noise, fads and the suburban ponzi scheme.

I don’t think any of those really disproves the filtering concept. Filtering doesn’t really describe causation, just the correlation – as demand drops (and therefore the potential rent income), so to does maintenance, and the units on the margins will filter down to more “affordable” prices. Each of those factors listed at the end could be construed, one way or another, as an influence on demand.

The rest of the Cap’ns post on the politics and emotions of gentrification and filtering up are spot on, however.

The fiscal benefits of density: While renting out old McMansions might be a challenge due to diseconomies of scale, Emily Badger looks at Asheville, NC and makes the fiscal case for density and urban infill development.

The whole idea is pretty simple. But it’s sort of baffling that we haven’t been looking at our land this way for years. Cities, Minicozzi laments, are woefully ignorant about exactly which types of neighborhoods and development put the most financial strain on public coffers and which kick in the most money. This is why Minicozzi has been deploying every metaphor he can think of – cash crops, gas tanks, french fries! – to beat home the math.

Fundamentally, this is the same concept as the Geoffrey West observation of urban agglomeration and the inherent efficiency it offers.

How to make use of the reverse commute: Perhaps someone should inform various secondary job centers along transit lines of their fiscal potential. Alon Levy looks at what’s required to make for successful secondary CBDs along rail transit lines, and what’s wrong with our current land use around suburban stations:

But really, the kind of development that’s missing around suburban train stations in the US is twofold. First, the local development near the stations is not transit-oriented, in the sense that big job and retail centers may be inconvenient to walk to for the pedestrian. And second, the regional development does not follow the train lines, but rather arterial roads, or, in cities with rapid transit, rapid transit lines…

In both cases, what’s missing is transportation-development symbiosis. Whoever runs the trains has the most to gain from locating major office and retail development, without excessive parking, near the train stations. And whoever owns the buildings has the most to gain from running trains to them, to prop up property values. This leads to the private railroad conglomerates in Tokyo, and to the Hong Kong MTR.

Commenter Jim notes how the DC region has a decent track record in this regard with Metro, but not with commuter rail:

The experience in Washington has been that when a Metrorail station (either an extension or infill) is proposed, the planners tear up their existing plans and write new ones for the area immediately surrounding the new station. Metrorail-catalysed TOD is a well understood and appreciated phenomenon. But no-one cares about commuter rail. Planners don’t assume that commuter rail stations will change anything, so don’t change their existing plans to accommodate them.

That’s the disconnect you have to fix.

Indeed – creating that symbiosis requires solving a bit of a chicken-egg problem. Still, some opportunities exist in the DC region. New Carrollton jumps to mind, both for Metro access for DC reverse commutes, as well as its mid-line location on the MARC Penn line. However, the challenge there is on the development side, not the transit service side.

Parking requirements matter: Downtown LA’s revival based on adaptive re-use might not have been possible without changes to LA’s minimum parking requirements. Making a place built pre-requirement conform is unnecessary, and shows how influential and destructive the requirements can be. It also speaks to the ability of changing regulations to make doing the right thing the path of least resistance:

Passed by the L.A. City Council in — yes — 1999 and at first applied only to Downtown, ARO gave the go-ahead for the conversion of historic and other older — and often under-used, under-appreciated or even abandoned — office buildings into residences. ARO was expanded in 2003 into various other parts of the city.

“[The Ordinance] provides for an expedited approval process and ensures that older and historic building are not subjected to the same zoning and code requirements that apply to new construction,” reads text on the city’s Office of Historic Resources site.

Fitting in with the econourbanist theory about reduced land use regulation allowing for the market to better address issues of supply, the response was impressive:

During an almost thirty-year period beginning in 1970, Downtown Los Angeles gained a grand total of 4,300 units in housing stock.

Then, between 1999 and 2008, Downtown gained at least 7,300 housing units just from long-term vacant buildings.

That said, it’s not like LA completely abandoned these regulations:

Shoup’s article notes that pre-ARO, developers were required per each housing unit to provide two or more parking spaces. Those spaces, Shoup emphasizes in his piece, were required to be on-site.

Post-ARO, Shoup’s piece says that the average number of on-site parking spaces fell to 0.9 in those converted, previously vacant buildings. Including off-site parking, the number was still 1.3 spaces per unit. That’s a 65% drop in required parking spaces in an area where many residents already self-select to reside in for reasons unrelated to having a multi-car garage.

Nearly one space per unit is still a lot of parking. Granted, this is LA that we’re talking about. The flexibility to meet that requirement off-site (flexibility likely required to make the adaptive reuse of historic buildings possible) speaks to the benefits of allowing such changes as a matter of right.

The point about residents self-selecting to live in such conditions is key, contrary to common NIMBY complaints – no one is forcing Angelenos to move in at gunpoint.

Different thoughts on transit service metrics: Jarrett Walker looks at San Francisco’s transit speed (same as it was 100 years ago, or slower) and offers thoughts on various metrics and the need to think about the reliability of the network as a whole.

My own work in this area has always advocated a stronger, more transit-specific approach that begins not with the single delayed line, but rather with the functioning of an entire network. Don’t just ask “how fast should this line be?” which tends to degenerate into “What can we do to make those forlorn buses move a little faster without upsetting anyone?” Instead, ask “What travel time outcomes do we need across this network?” Or turn it around: How much of the city needs to be within 30 minutes of most people? — a question that leads to those compelling Walkscore travel time maps, which are literally maps of individual freedom.

Things that matter

Museo Guggenheim Bilbao - from La Tête Krançien

Mammoth directs our attention to this post from LA Times architecture critic Christopher Hawthorne, talking about the systemic flaws of lists of the best buildings (and architecture criticism in general):

When Vanity Fair magazine recently released the results of a survey ranking the most significant pieces of architecture of the last 30 years — with Frank Gehry’s Guggenheim Museum in Bilbao, Spain, topping the list — the poll was met with more than a little grumbling. Some people griped about the many architects, including Richard Meier and Daniel Libeskind, who voted for their own work (talk about a vanity fair!); others noted that the average age of those polled, a group including architects, critics and academics, seemed to be pushing 70.

Mammoth also notes the tendency for architects to nominate their own buildings to the list – particularly the ones that don’t show up on any other lists. Another criticism was the list’s complete whiff on any green architecture, spurring an alternative contest with an emphasis on sustainability. Hawthorne delves into the more fundamental issue:

Asking voters to submit a list of single buildings necessarily produces results that give a skewed view of the way architecture — and more important, the way we think and write about it — has evolved in recent years.Among critics and architects alike, there has been a growing understanding that architecture is not just about stand-alone icons but is tied inextricably to real-estate speculation, urban planning, capital flows, ecology and various kinds of networks. Similarly, ambitious architecture criticism now means a good deal more than than simply writing about impressive new landmarks, green or not, produced by the world’s best-known firms […]

Maybe, in other words, the most important achievement in green architecture over the last 10 or 30 years is not a single building at all. Maybe it’s a collection of schools or linked parks or the group of advisors brought together by a young mayor somewhere. Maybe it’s a new kind of solar panel, a tax credit or a zoning change. Maybe it’s tough to hang a plaque on — or photograph for a magazine spread.

Emphasis is mine. The same logic applies to the environmental benefits of urban density and city living, as opposed to just adding LEED certified buildings. How about hanging that green award on a carbon tax or the elimination of parking minimums.

Changing suburbia

Some suburban items to share today:

Design: Infrastructurist takes a look at the problem of culs-de-sac (which I believe is the proper plural of cul de sac).

Commenters take note of some serious issues with this particular study, but the general point still stands – culs de sac remove key links from the street network, requiring longer and more circuitous routes to get to the same destinations. Developments of these kind of street patterns are no small part of America’s long history of vehicle miles traveled increasing far faster than the rate of population growth.

Diversity: The Washington Post has an article on the changing face of suburbia – more socially and economically diverse, and dealing with new sets of problems that many of these communities have never had to deal with before:

Demographers at Brookings say suburbs are developing many of the same problems and attractions that are more typically associated with cities. And cities, in turn, have been drawing more residents who are young and affluent, so the traditional income gap between wealthier suburbs and more diverse cities narrowed slightly.

“The decade brought many cities and suburbs still closer together along a series of social, demographic and economic dimensions,” said the report, titled “State of Metropolitan America.”

The other substantive point is about how Americans perceive their surroundings (urban, suburban, rural) compared to how their city and their urban economy actually functions:

The report outlines a decade in which several demographic milestones were passed as the nation’s population topped 300 million midway through. About two-thirds of Americans live in the nation’s 100 largest metropolitan areas, virtually all regions with populations of 500,000 or more.

“We think we’re a small-town nation,” Berube said. “But small towns exist because they’re connected to something bigger, which allows residents to make a living.”

Density: Ryan Avent has long marked the economic benefits of density and the nature of urban agglomerations, but he has an interesting point on the marginal benefits of added density, noting that modest increases in the less dense suburbs could have a troubling impact, while modest increases in the already dense core, already designed at a walkable scale, would have serious benefits for local retail.

So let’s think about the effects of doubling density in Fairfax and the District. Now on the one hand, the benefits to doubling density in Fairfax are likely to be larger than those in Washington for reasons of scale alone — in the Fairfax example, more people are added. That makes for a deeper labour pool, a larger skills base, and so on. On the other hand, Fairfax density is likely to be less effective density. Fairfax is built in a fairly standard, suburban way. It’s not built at a walkable scale, the road system is arterial rather than gridded, transit options are limited, and so on. Doubling density, absent major infrastructure improvements, might actually reduce the metropolitan access of Fairfax residents.

Not so in the District. Yes, with more people roads, buses, and the Metro would be more heavily taxed. At the same time, every neighborhood would become individually more convenient. Brookland is fairly low density for a District neighborhood, but it’s basically built to be walkable. Were density in Brookland to double, the retail and commercial options within easy walking distance of Brookland residents would more than double.

The problem with doubling the density in a place like Fairfax County, aside from the infrastructure issues that Ryan highlights, is that you’d end up with a place that’s stuck in the no-man’s land of density – too dense for the auto-oriented infrastructure to function smoothly, but not dense enough to really tap into the critical mass and benefits of walkable urban places.

City Block

a work in progress…