The size of the pedestrian city

In a previous post I identified the size of the pedestrian city as on the order of 50,000, let’s do this a bit more systematically.

Elements of Access: Transport Planning for Engineers, Transport Engineering for Planners. By David M. Levinson, Wes Marshall, Kay Axhausen.

Let’s illustrate with some assumptions:

  • One-way Travel time budget (B) = 0.5 h
  • Walking speed (S) = 5 km/h
  • Walking network radius (Rn = S/B) = 2.5 km
  • Network circuity (C) = 1.25
  • Walking euclidean radius (Re = Rn/C) = 2 km
  • Walking euclidean area (potential) (Ae=Pr*Re^2) = 12.56 km^2
  • Population density (D) = 5,000 persons per km^2 [As a point of reference, the current population density of Manhattan is 27,485/km^2, which I would argue is only enabled by 19th century technologies like elevators and transit. Rome currently has a population density of 2,101/km^2]
  • Population within TTB threshold (P=D*Ae) 62,800

Obviously you can construct a spreadsheet and play with population densities, which are highly disputed in ancient times. One sees claims that the City of Rome in ancient times had a population of 1 million people, but it is unclear over what area that was measured, and some estimates of those densities far exceed the densities of modern elevator cities (like Manhattan). I believe it is possible that high crowding occurred, but I think it unlikely that such crowding extended over large areas.
Also one can have a pedestrian city that exceeds the one-way walking travel time budget, but not a city one interacts with on a daily basis. This is more the equivalent of adjacent and overlapping cities, and likely have multiple cores.

To game or not to game: teaching transportation planning with board games

Evaluation of Transportation Board Games from To Game or Not To Game by Huang and Levinson
Evaluation of Transportation Board Games from To Game or Not To Game by Huang and Levinson

Recent working paper:

  • Huang, Arthur and Levinson, David (2011) To game or not to game: teaching transportation planning with board games. (working paper)

Traditional “chalk and talk” teaching in civil engineering has gradually been replaced with the idea of active learning focusing on encouraging students’ knowledge discovery with innovative pedagogical methods and tools. One interesting tool is the board game. This research examines the efficacy of adopting transportation board games as a tool in graduate-level transportation planning and transportation economics classes at the Department of Civil Engineering of the University of Minnesota from 2008 to 2010. In these classes, a weekday night was scheduled for playing transportation board games. Students were asked to evaluate the effectiveness of the games on their learning and to
write a self-reflective paper about their findings. The majority of the students reveal that their understanding of the planning process, network deployment, and practical issues, and and their ability to form opinion about transportation planning has been improved. Their summaries on the game economy and its implications on planning validate that their understanding obtained from this game process has met the pedagogical goals. Our analysis further shows that students who are moderately/highly visual, sensing, active, or sequential, all else equal, tend to learn more effectively through this approach than those who are not. Overall, this research suggests that properly incorporating board games into the curriculum can enhance students’ learning process in transportation planning.

City of North Oaks, Minnesota

I did not know until recently about the: City of North Oaks:

“Located in the Twin Cities, just northeast of St. Paul, Minnesota, North Oaks is a unique suburban community.  With a rich history and emphasis on retaining the natural environment, North Oaks celebrated its 50th anniversary in 2006.
Approximately 4500 residents call North Oaks home.  Because residents’ properties extend to halfway across the road, all residential roads in the City are private and for the use of North Oaks residents and their invited guests only.
The City owns no property.  With residents owning the roads, the North Oaks Home Owners’ Association owns the park and recreation areas and trails throughout the City.
This website is run by the City of North Oaks and serves as a major communications tool for the entire community. Here you can find information about the operation of our local government, homeowner’s associations, community news, promotion of local events and answers to many frequently asked questions. “

I would visit, but I would not be allowed in, unless someone scores me an invite. I wonder if their international roughness index is better or worse than similarly situated suburban subdivisions.

(Via Bruce Benson.)

Open Source, Open Content, Open Campuses … New Apple HQ


Alexandra Lange at Design Observer does not like the New Apple HQ

Wouldn’t it have been more radical for Apple to double down on an actual town? To act more like J. Irwin Miller in Columbus than CG chairman Frazar Wilde in Bloomfield. Miller hired Alexander Girard to spiff up Main Street, and masterminded adaptive reuse of the old storefronts to provide his employees and his neighbors what they needed in town. Cupertino leaders fell all over themselves in their desire to keep Apple’s taxes in town, but wouldn’t it be better to benefit from some of its knowledge and physical assets?

This is a classic trade-off. Interaction between people is of course good for generating ideas, productivity, etc. But which interactions, between which people, do you want to maximize: Interaction within the firm (a la Apple’s HQ) or interaction between the firm and the outside world (Lange’s proposed solution)? Given finite time budgets, more of one means less of the other. For Apple, with its secretiveness part of the formula of its success, the answer is obvious. For many universities, the issue is the same (town vs. gown), even without the profit motive. The most productive work-related random interactions I have are on-campus, not between me and some random town-folk (sorry Minneapolitans I meet on the street).Crashed2 This is the same argument as Eric Raymond puts forth in The Cathedral and the Bazaar, which argues in favor of the Bazaar model of software development (which gives us Open Source products like Linux) rather than the Cathedral (Microsoft or Apple, e.g.). Open source and open content are good things (my Open source and open content projects include the Metropolitan Travel Survey Archive, Simulating Transportation for Realistic Education and Training, some wikibooks, and the Journal of Transport and Land Use), and interaction with the community is a good thing, for the community. As an employee of a not-for-profit University, I am enabled to do these community-benefitting works.

But if open dissipates the quality of internal interactions, or costs the profits necessary to justify a high fixed cost investment, the reasons for resistance are quite clear. Apple’s business model is such that it cannot make large multi-year investments if someone else can get their ideas and come to market at the same time without the investment. In some areas, those with high fixed costs but low excludability (ideas are easy to steal and hard to protect, hence patents) and low rivalry (my possessing an idea does not prevent you from possessing it) require secrecy for development. If the fixed costs of development were low relative to the variable costs of production, the isolation and secrecy would be less critical, since the cost of production would be proportional to units made, that does not describe software, where all of the investment is up front.
The Linux strategy of openness works quite well at producing low-level operating systems (which underlie Android phones, servers, cable boxes, and airplane entertainment systems (see figure) among the countless other systems out there), but not well at User Interface, for that someone needs to come along and put something proprietary on top, or hardware/software integration. Google did a UI stack on top of Linux with Android and essentially gave it away in exchange for advertising revenue (if they are not selling to you, they are selling you). This is a different business model.

Feat of feet of street


Getting Around Minneapolis reports on Feet of street :

The brilliant blog Mapping the Strait posted an infographic yesterday comparing the feet of street per resident of 8 American cities.
The metric is supposed to give an indication of the amount of infrastructure per resident, to augment standard persons per area measures of population density.
According to the Design Guidelines for Streets and Sidewalks, Minneapolis has 1,423 miles of roads and vehicle bridges, not counting freeways. My rough Google Earth measurement of freeways within city limits is 30.3 miles (that includes the part of 62 on the border but does not include highways 55 & 121 because I think they are in the city’s measurement, although that’s just a guess). That makes for 7,673,424 feet of streets and highways, or 20.1 feet for each of the 382,578 residents counted in the 2010 census. We’re closer to Detroit, Phoenix or San Antonio than Philadelphia, Los Angeles, or Chicago on this count.
That doesn’t seem to be an unreasonable result to me, although by measuring residents only you ignore the significant market for infrastructure represented by workers. In that case cities such as San Antonio or Houston that contain most of their employment catchment area in their city limits are going to be more accurately portrayed by this metric. One of the commenters at Mapping the Straight asked for this metric by area of paved surface – I think using lane feet would be better than centerline feet, but probably less widely available. Fun to think about anyway.

Docklands Light Railway, Charing Cross, Jubilee, and the case for dynamic planning


London Reconnections discusses possible extensions to the Docklands Light Railway, shown in the figure. The official version is here: DLR – Development Projects – The future of DLR – Where we go Next.


The privately operated (under franchise agreement) DLR opened in 1987, after 3 years of construction and just a few years after conception (in 1982 according to TfL (though antecedents can be seen as early as the 1973 Docklands Study, according to the London Dockland Development Corporation) ), to serve the emerging Docklands regeneration project centered at Canary Wharf.


Containerization of shipping changed the nature of the industry, which migrated in the 1960s and 70s from London to Felixstowe. The Docklands development replaced the newly abandoned shipping docks in East London with an emerging financial center, an American-like downtown for London. Almost immediately upon opening, construction started on extensions. Success begat success, and proposals and funding for extensions to this new, Docklands-centered automated public-transport technology continued to flow in. As can be seen from the top map, extensions continue to be proposed, notably to Charing Cross. The early DLR segments took advantage of abandoned railway lines, and while not a green-field, it was a relatively open brown-field canvas on which to work.

charingcrosstextCharingCrossJubilee1The planning for the Jubilee Line, then the “Fleet Line” (after Fleet Street and the River Fleet), apparently began around 1965. The first section opened in 1979, two years after the Silver Jubilee of Queen Elizabeth for which it was named. The line temporarily terminated at Charing Cross station, as shown in the poster. It was to continue eastwards, along Fleet Street.In 1999 the Jubilee Line was extended to Canary Wharf as well, but this eastward extension resulted in the abandonment of the then 20-year old extension to Charing Cross, as a new routing split from the old in Green Park. The decision to do this can be seen as early as the 1990 Jubilee Line Extension options map. At this point the expensive Charing Cross station was just over 10 years old. Stations are often more expensive (and require more tunneling volume) than the lines which they connect, so this is a major rethink, not some temporary train halt which was subsequently bypassed. Jubilee Line Extension is said to have cost 3.5 billion pounds, which delayed other significant potential construction projects, such as Crossrail and the Chelsea-Hackney line.Jubilee1990

There are several points to be made about this:

  • No one in the 1970s anticipated abandoning the Jubilee line portion of Charing Cross station, certainly not so soon after construction.
  • No one in the 1970s (or 1980s or 1990s) anticipated that the DLR might one day reoccupy Charing Cross station, or even construct such a large cross-London network centered on the Docklands. (I did see speculation about this in the first decade of the 2000s). While the Underground system is centered on the Square Mile of the City of London, with many branches and a Circle Line, DLR has a new hub, with a new technology, that inter-connects with the old at several key stations, and if the extensions are built, at several more.
  • In order to build anything, you must have a vision. Rarely does construction start without a fixed end point in mind (this is not SimCity) That construction once made is largely irreversible, though it may be abandoned, and it provides opportunities for reuse, it creates “facts on the ground” that are hard to undo. The City of London street network is a perfect example. Even after the Great Fire of 1666 or the bombings of World War II, it greatly resembles the facts on the ground at the time of William the Conqueror.
  • In order to move forward, you must be willing to abandon old visions. The DLR and Jubilee Line Extensions were new visions, built on top of (and beneath) old constructions, not old visions. They were even willing to abandon one major fact on the ground (Charing Cross station) so as not to be wed to a vision that no longer worked.
  • Facts on the ground create new constraints, new opportunities, new ways of looking at the world. There are many possible lines in a network, but only a few can actually be built. We are far from “optimal”, and I suspect we always will be, but we need to consider what is the best decision given the world as it exists, not the world as it might be according to some plan.

We ought not be too locked into our plans, we forego many opportunities by clinging to the zombie maps of long-dead officials.

Is Vision Necessary?

Some nice naval-gazing about the planning profession, Thomas Campanella writes: Reconsidering Jane Jacobs: The Death and Life of American Planning: Places: Design Observer:

“The second legacy of the Jacobsian revolution is related to the first: Privileging the grassroots over plannerly authority and expertise meant a loss of professional agency. In rejecting the muscular interventionism of the Burnham-Moses sort, planners in the 1960s identified instead with the victims of urban renewal. New mechanisms were devised to empower ordinary citizens to guide the planning process. This was an extraordinary act of altruism on our part; I can think of no other profession that has done anything like it. Imagine economists at the Federal Reserve holding community meetings to decide the direction of fiscal policy. Imagine public health officials giving equal weight to the nutritional wisdom of teenagers — they are stakeholders, after all! Granted, powering up the grassroots was necessary in the 1970s to stop expressway and renewal schemes that had run amok. But it was power that could not easily be switched off. Tools and processes introduced to ensure popular participation ended up reducing the planner’s role to that of umpire or schoolyard monitor. Instead of setting the terms of debate or charting a course of action, planners now seemed content to be facilitators — ‘mere absorbers of public opinion,’ as Alex Krieger put it, ‘waiting for consensus to build.’ [9]
The fatal flaw of such populism is that no single group of citizens — mainstream or marginalized, affluent or impoverished — can be trusted to have the best interests of society or the environment in mind when they evaluate a proposal. The literature on grassroots planning tends to assume a citizenry of Gandhian humanists. In fact, most people are not motivated by altruism but by self-interest. Preservation and enhancement of that self-interest — which usually orbits about the axes of rising crime rates and falling property values — are the real drivers of community activism. This is why it’s a fool’s errand to rely upon citizens to guide the planning process. Forget for a moment that most folks lack the knowledge to make intelligent decisions about the future of our cities. Most people are simply too busy, too apathetic, or too focused on their jobs or kids to be moved to action over issues unless those issues are at their doorstep. And once an issue is at the doorstep, fear sets in and reason flies out the window. So the very citizens least able to make objective decisions end up dominating the process, often wielding near-veto power over proposals.
Late in life, even Jane Jacobs grew frustrated with the timidity of planners — Canadian planners this time. In an April 1993 speech — published in the Ontario Planning Journal — she lamented the absence of just the sort of robust plannerly interventionism that she once condemned. Jacobs read through a list of exemplary planning initiatives — the Toronto Main Street effort; the new Planning for Ontario guidelines; efforts to plan the Toronto waterfront; and plans for infill housing, the renewal and extension of streetcar transit, the redevelopment of the St. Lawrence neighborhood, and on and on. And then she unleashed this bitter missile: “Not one of these forward looking and important policies and ideas — not ONE — was the intellectual product of an official planning department, whether in Toronto, Metro, or the province.” Indeed, she drove on, “our official planning departments seem to be brain-dead in the sense that we cannot depend on them in any way, shape, or form for providing intellectual leadership in addressing urgent problems involving the physical future of the city.” This, I hardly need to add, from a person who did more than any other to quash plannerly agency to shape the physical city. [14]


The net is the planners have no vision, and no one else does either. The question then arises, is vision necessary, or even good? Those who believe in the merits of the decentralized world would argue that vision, especially big visions, is more likely to do harm than good.
I would argue we need some form of vision, on which to base current decisions. But we need to continually re-evaluate those decisions, and that vision. We cannot get stuck on zombie plans, which is what visions often lead to, but we also cannot act aimlessly.

Zombie Transportation, Irreversibility, Planning Limbo, and Why Projects Never Die

A few days ago I was quoted discussing the so-called high-speed rail project between Chicago and the Twin Cities saying “It’s deader.”
Peter Bell discussed the many “Near death experiences” of the Central Corridor LRT, which recently got fully funded from the federal government, and is now, almost assuredly, irreversible, as these things go.
Well, of course, in transportation, nothing ever truly dies as long as the line on the map is a memory in the mind of an advocate. A decision to not build a project is easily reversed, since “no” involves no investment in fixed costs, unless something is done in its stead. This is especially a problem if the right-of-way for the facility is being preserved, through either land purchases or prohibitions on development.

Following the lead of John Quiggin, who titled a book “Zombie Economics: How Dead Ideas Still Walk among Us“, we might call these old ideas “Zombie Transportation”, projects that are now “bad” (or at least no longer “good”) ideas, effectively seemingly dead, yet still live in people’s minds (and occasionally, like the California HSR, get partial funding before their plug is eventually pulled).
There are lots of other projects one can think of that were lines on maps for decades before being realized. Maryland 200 (the Inter-County Connector), Minnesota 610 are two that come immediately to mind, on the map for 60 and at least 40 years respectively.

In many cases, the problem is simple, ruthless, benefit/cost analysis, the B/C ratio, which may have once been above 1.0, falls to a lower level due to changed circumstances, increased costs due to environmental or other concerns, or a change in demand associated with different finance (tax to toll) mechanism or price of energy. Yet because it is a “commitment” (political, or moral) to a community that their turn will come, they too will get their line built, the line on the map never comes off the map.

Once a project is completed and open, it is essentially irreversible, it will almost never be shuttered before it physically fails (a few exceptions to be noted: e.g. collapsing urban freeways in San Francisco), or requires replacement (Streetcars in many US cities). And even then, many facilities which should be shuttered continue to be maintained and operated, and later reconstructed instead. The difficulty with gravelization is an extreme example of this.

The End of Traffic and the Future of Access: A Roadmap to the New Transport Landscape. By David M. Levinson and Kevin J. Krizek.
The End of Traffic and the Future of Access: A Roadmap to the New Transport Landscape. By David M. Levinson and Kevin J. Krizek.

We need a better system for truly killing bad or obsolete ideas in transportation, for culling the losers or the no longer winners. Otherwise, agencies will look at decade old maps, say to themselves: “what remains unfinished”, and proceed along to build zombie facilities despite newer priorities rising to the fore and old ideas ceasing to be effective.

Does Brasilia work?

Tyler Cowan on Brasilia … Does Brasilia work? : “”

There are a few quick lessons:
1. Sorry Jane Jacobs fans, planned cities do sometimes work. Take a look at postwar Germany too.
2. “Planned” cities are often less formally planned in their entirety than you think, and that is true for the greater Brasilia area. Brasilia is a mix of planned and unplanned elements, and it’s the mix which (mostly) works. We should not demonize either the “planned” or “unplanned” aspects of that blend per se.
3. Even when matters are quite screwed up from the policy or optimality side, mobility enforces an equality of average rates of return. This is one of the most neglected insights of economics.