Origin density at transit stations

Origins tend to be rather more spread out, and it requires pretty high density to generate more riders than a Park-and-Ride, which generates one rider per 400 SF. A three-story apartment is actually worse than a Park-and-Ride--not everyone in those apartments will take transit, and parking + landscaping will take up over two thirds of the parcel.  A 2-3 acre bus depot will likewise collect more riders than a garden apartment. So making a fuss about the density of origins near a transit station is rarely worthwhile across most of America. 

Further, origins highly concentrated on a small fraction of land parcels, and highly concentrated on buildings located within those parcels. As getting places requires getting to the front door, it's that access that matters for transit supportive density, while most origin destination calculations are made using metrics like units per acre. Pure geographic coverage is a terrible metric for access--most of the land is empty or occupied by things like private yards. 

Transit supportive density is a bit of a red herring

"Transit supportive density" is a bit of a red herring. The Utah Transit Authority build a very successful transit system by destinations where parking was expensive to build (downtown, universities & colleges, hospitals) and using a mix of PnR and transit centers to aggregate origins. So for making transit work, what really matters is destination density--how much stuff is within a walkable distance (10m) of the transit station? 

TOD > Missing Middle

Using public transit to fix car-dependence is a failing strategy. Providing marginal transportation to marginalized groups (teenagers, people with disabilities, older seniors) is at best a band-aid and at worst a sop. Further, no level of public transit provision will ever be able to fully replace automobility. Hence, undoing car dependence is largely a land-use problem: allowing the magic of density and mixed use to shorten trip distances and enable non-auto modes. Since most of the magic in transportation shifts happens at a pretty high threshold, it's key to focus on land uses in a small portion of critical places. From a transportation perspective, enabling good TOD at a few places beats enabling Missing Middle everywhere.

Not to say that the Missing Middle doesn't matter. Most of America is caught on the threshold where the densest multifamily that's financially viable is the 3-story 'garden' apartment with a huge parking lot, such that until land prices rise to a level where 'wrap' apartments with structured parking become viable, almost no new apartments get built--rather, more and more 3-story apartments get built, just at increasingly peripheral locations. 

TOD without transit

Of course, for places without fixed guideway transit, it's easy to claim that TOD doesn't matter. That misses the point. Read Calthorpe, and you quickly understand that TOD is just his early "Pedestrian Pocket" wrapped around a transit station, with all the same elements: higher density, a mix of uses, and a walkable street network. Counter-intutitively, there is no need for a transit station for these elements of TOD-ness. 

The 'bones' of a walkable street network and the regulatory context of permitting a mix of uses and higher density are simple to establish. But to actually get density, and to get the commercial uses supported by a local population, is much harder. Sandy Civic Center Trax in Utah tried for decades before achieving even minimal transit supportive density and barely supports minimal retail by the station even now. 

Hence, TOD: a way to increase the footfall traffic at a location, so commercial amenities at the station can draw not only from the local population, but the commuter population. It's not by accident that Calthorpe drew TOD as one-sided--he was omitting the massive commuter parking lot across the arterial road from the picture.

Picture any civic center, downtown, and urban district you've ever visited, and you'll see the same elements: a density of activity, a mix of uses, and a walkable street network. And on the periphery, some large parking lots and a major arterial. Self-contained autarky is impossible; local density alone cannot supply the dollars to support the commercial services or supply the staff for the commercial retail/services--any center must draw on people from outside the center and must facilitated people traveling to do so. 

But the key element to having and sustaining a pedestrian pocket is prioritizing internal circulation is prioritized over regional access. And that, rather than transit access, is the core of TOD. A transit station wrapped in parking lots isn't TOD. A transit station with a multi-level bus transit center isn't TOD. Because in both cases, the area near the station is designed to facilitate regional access. It's not by accident that transit agencies are bad at TOD--it's contrary to their institutional mission of providing regional transportation. 

The purpose of TOD is to use a transit station to facilitate the existence of a pedestrian pocket, and the elements that represent TOD have very little to do with transit stations. Rather, they are the principles of facilitating pedestrian-scale urbanism, and those principles can be applied without the need for a transit station. 

Motor Socialism

 We have oriented our infrastructure investment to guarantee the provision of roadway and parking capacity in amounts necessity to eliminate scarcity. "Motor socialism" if you will. And our society has become structured around that investment schema, such that a lot of people are sustained by the status quo. A rupture with that is going to be bad for a lot of people, and they are going to fight hard to continue and preserve it.

Facilitating traffic - attraction or circulation

Picture any civic center, downtown, and urban district you've ever visited, and you'll see the same elements: a density of activity, a mix of uses, and a walkable street network. And on the periphery, some large parking lots and a major arterial. Self-contained autarky is impossible; local density alone cannot supply the dollars to support the commercial services or supply the staff for the commercial retail/services--any center must draw on people from outside the center and must facilitated people traveling to do so. But any center must also facilitate circulation within itself*, and it is that tension between attraction and facilitation that makes urban traffic such a muddle**. 

That tension can be resolved in favor of either, but results in very different outcomes. If attraction is subsidized, you get a very good network of higher speed roads between pods of development. If circulation is subsidized, you get a very high-quality pedestrian realm, comfortable local traffic, but very poor access for traveling long distances. Neither resolution is reliably superior to the other, but rather which should be preferred is context dependent.

 

*Also what makes freeway interchanges so hostile to urbanism and incapable of being 'centers': an interchange of an expressway with an arterial generates four islands of highly accessible land, equal in dignity, but prohibits circulation between them. 

** Grade separation resolves the urban traffic muddle but is expensive to implement. The contrived solution is grade separation--witness endless Chamber of Commerce plans for skybridges and pedways, and highway megaprojects like Boston's Big Dig, or Los Angeles triple-track rail trench. It's not a new solution--practically as soon as railroads emerged, demands for grade separation followed, generating elevated and subway lines. 

Suburbia Requires a New Transportation Technology

We built the first suburbs based on passenger trains, the next set based on grade-separated urban rail, and a third set based on streetcars. Then we did it again with the automobile, and again with the limited access highway. In every case, it was a new transportation technology making previously inaccessible land more accessible and making it accessible in such volume that an urban development pattern built on cheaper-then-previous-urban land happened. Each time, over time, the flood of new resource was exploited, but further exploiting it required greater and greater investment, leading to declining returns, until things petered out, and the financial of the new development pattern no longer worked. 

No one recognizes this today, because for three generations we had a massive subsidy regime where we taxed gasoline to pay for new limited access highway miles. That subsidy regime went bust in 2008, and the last fifteen years have been a scramble to prop it up. Because there is a lot of money invested in suburbia continuing. There are entire industries predicated on turning raw land into suburban houses, and entire polities dependent on that process, and there is an awareness if that engine stops running, our entire economy might tank. (Japan's did. China's is). 

So the smart money gets that another round of suburbia requires a new transportation technology. So there is a lot of investment in both flying cars and connected and autonomous vehicles*. Both are oversold, because the people developing both are trying to recruit enough investment money to actually develop a saleable product, so they overstate the benefits their product will provide. The most basic way they do that is talking about how much time drivers will save, which sounds great to drivers. But to anyone involved in infrastructure (planners, transportation economists, engineers), everyone is very clear that driver time is not the limiting factor in our transportation system but rather road capacity, and driver-time has heretofore been a limitation on driver utilization of road capacity. So even if every vehicle becomes a CAV, traffic will not disappear, and indeed, will likely grow worse.

I say new technology because old technologies aren't going to save us. We are already familiar with their characteristics, with their limitations, and make use of them where appropriate and efficient. But having another round of suburbanization relies on a transportation technology sufficient to make a massive volume of previously inaccessible land available for development. 

My personal bet is on flying cars, simply because they don't have right-of-way costs. But flying cars have the same issues as automobiles, if not worse: they take up a lot of space. So they may be useful at the periphery, they don't solve the problem of making trips between two regimes: the low-D autocentric regime, and the high-D geometry-hates-cars regime. 

Urbanization and Transportation

The spatial arrangement of urbanization is determined by trade in whatever is valuable. If that thing is rare or dense, you build cities at natural crossroads. If it's bulky, you get cities near navigable rivers. If it relies on combining things, you build around ports. If you rely on bulk inputs, your build at the fall line. 

Urban Regimes

It's critical to recognize that for travel behavior there exist different urban regimes, which can be defined in terms of the "D variables" (Density, Diversity, Design). And in one regime, it's painfully absurd to do anything but drive. Distances are long, routes are indirect, all the infrastructure is auto-centric, parking is plentiful and free. And that regime characterizes 95% of the urban area. But when distances are shorter, routes are direct, you've got infrastructure that is safe and humane for people not in cars, and parking is painful. Useful transit exists. And in the latter regime, that car is no longer the most efficient mode of transport.

And when that happens, we should stop privileging the automobile as the most efficient mode. Even conceptualizing what it would be like to privilege another mode is astonishingly powerful, because it rapidly leads to a catalogue of things we have to do for cars: the space we provide, the risks we tolerate, the funding we provide, the denial of access, the regulation of unrelated matters (Daylight Savings Time), the distortion to every development, etc. And we have to ask: "If cars are no longer the most efficient mode, why are we spending millions prioritizing the movement of cars, and mandating everyone else spend millions providing for the storage of cars"?

The simple answer is that for most trips, one end of a trip lies in the auto-centric regime, and it's a choice between imposing costs in the smaller area where cars are less efficient, or in the larger area, where cars are more efficient. And benefitting the suburbs to the detriment of central cities was official US policy for decades. It wasn't until the "Urban Transportation Problem" hit, when congestion outstripped road building, that thoughtful people realized building their way out of congestion was impossible--traffic was growing faster than the capacity to pay for it, even as the cost of paying for it became exponentially higher. And then we started building rapid transit. (And saving older transit systems). 

Geometry hates cars

The simple fact is that geometry hates cars. Cars are an amazing way to travel, and for most places in America, nearly the only way to travel. But cars take up a lot of space (most of which is parking). Most places, that's a non-issue: We've mandated a 30-year supply of both roads and parking. But for anyplace that existed prior to those mandates (any main street, downtown or CBD more than 50 years old), those mandates didn't exist, and adding either lanes or parking requires demolishing buildings. 

We all understand that adding a lane for a block doesn't do anything. If it's going to do any good, it's got to go on for a good long while. So adding a lane for five miles requires acquiring five miles worth of front yards. And fighting with a few thousand property owners. And that's very difficult to do these days--lawsuits and lawsuit-induced delays are an inevitability. 

I've written previously about the extraordinary racism of urban highways, but here is the nut: the land was never cheap, the marginalized people it was taken from just lacked the legal rights to effectively contest it, and get a fair price for what was being taken. Where they did (DC) you'll find a near-complete absence of urban highways. 

Cars require a lot of land. They aren't making any more land. With fixed supply, as the demand rises, so does the price. So every bit of land devoted to cars is expensive and mandating that land be devoted to cars is just imposing a cost that, given free choice, people would not choose to pay.