Up or Out: Travel Demand and Thirty Minute Cities

Adapted from Levinson, D. and Krizek, K. (2017) The End of Traffic and the Future of Access. Network Design Lab. Cross-posted on the ITLS Thinking Outside the Box  blog.

Each technological advance in mobility over the past 200 years increased the size of metropolitan areas. The ability to go faster, either owing to new technologies or more completely deployed and deeply connected networks, allowed people to reach more things in less time. The Underground drove the expansion of London, streetcars did the same for many American cities,[a] while trams and trains made Sydney, Melbourne, and Brisbane among others, and highways have exploded the size of cities everywhere. Historically, the time saved from mobility gains was reflected mostly in additional distance between home and the workplace, maintaining a stable commuting (home to work) time.

Will autonomous vehicles follow the path well worn by earlier technologies?

Fast, driverless cars that allow their passenger to do things other than steer and brake and find parking impose fewer requirements on the traveler than actively driving the same distance. Decreases in the cost of traveling (i.e., the availability of  safe in-vehicle multitasking) makes travel easier. Faster roads arise because of capacity gains from vehicle automation (due both to closer following distances and narrower lanes, even more practical with narrower vehicles fit to serve the single passenger they usually carry). Easier travel means increases in accessibility and subsequently increases in the spread of development and a greater separation between home and work, (pejoratively, `sprawl’), just as commuter trains today enable exurban living or living in a different city.[b] Autonomous automobility reinforces the disconnected, dendritic suburban street grid and makes transit service that much more difficult (as if low density suburbs weren’t hard enough). People will live farther ‘Out.’

However, concomitant with automation is the emergence of the sharing economy, with at least some people transitioning from today, where the typical Australian owns their own car, to mobility-as-a-service (MaaS) — automated taxis. This is more likely in larger, central cities where taxis are common, auto ownership is already difficult, and parking scarce and expensive. In this world, while the total cost of travel drops as vehicle ownership costs disappear, the cost per trip might rise, as the cost of ownership is allocated to each trip. This reduces travel demand.

Driverless cars which can be summoned on-demand allow people to avoid vehicle ownership altogether. This reduces vehicle travel, as people will pay more to rent by the minute than exploit the sunk costs of vehicular ownership. By saving total expenditures on transport, more funds are available to pay for rent in cities, and more trips are by walk, bike, and transit. People who seek the set of urban amenities (entertainment, restaurants, a larger dating pool) will find these amenities increasing in response to the population. The greater value in cities with the new more convenient technology leads to more and taller development. (Hence the use of the word ‘Up.’)

At first blush, ‘Up’ and ‘Out’ appear to be contrasting scenarios; they are not exclusive, however. More people living in the outer suburbs or exurbs does not mean fewer people live in cities, because the overall size increases (with more people overall). Sydney for instance, is expected to grow from just over 5 million to about 8 million people over the next four decades.

Similarly, as the cost of travel decreases, people will be more willing to live in locations far from where they work. At safe speeds of 160 km/h on freeway lanes exclusively dedicated to automated vehicles, the commuting range expands widely. From Sydney in this new world, Newcastle can be reached an hour on road, and Kiama and Katoomba are even nearer.

Sydney planners have recently proposed the benchmark of the “30-minute city“, the idea that most people can find work, school, or daily shopping within 30 minutes of their homes by walk, bike, or transit. The threshold of 30-minutes is roughly equal to today’s one-way commute in Sydney (actually 35 minutes), shorter by car (26 minutes), longer by train (62 minutes) according to BITRE. The long times by train are because trains are designed to serve longer distance trips, and focus on the Central Business District.

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.

The 30-minute city can be achieved through a combination of transport and land use strategies. On the transport side is the question of how fast and how direct the transport network is. On the land use side is the question of where desired activities are located relative to each other.

If the 30-minute city is defined for walk, bike, and transit as the relevant modes, with mobility-as-a-service easily available on-demand, the Up Scenario works best, though getting one-way commuting times for train users down from 60 to 30 minutes is a large ask. In contrast, the Out Scenario can continue to enable a 30-minute city for privately owned autonomous vehicles so long as jobs don’t centralize further in downtowns.

The interplay of AVs and road pricing is especially important. While autonomous vehicles may eventually double or quadruple road capacity, total demand will rise as well due to population growth, so long as people continue to work, shop, and play outside-the-home at today’s rates, even more if traditional patterns of induced demand hold.

It is quite possible that sharing remains a niche while most people choose to own their own cars — the ‘Out’ scenario dominates. Thus, exurbanization and AVs better leverage newly available capacity. But, in the absence of pricing, and with cheap energy, there is little to discourage tomorrow’s privately owned AVs from circulating empty on the road network rather than pay for high prices of parking, and thereby slow travel for everyone else. This possible outcome is so obviously bad, it suggests road pricing or similarly effective regulation in some form is likely.


 

[a] See Levinson, D. (2008). Density and dispersion: the co-development of land use and rail in London. Journal of Economic Geography, 8(1), 55-77 and Xie, F., & Levinson, D. (2009). How streetcars shaped suburbanization: a Granger causality analysis of land use and transit in the Twin Cities. Journal of Economic Geography, lbp031.

[b] For more on this reasoning, see Chapter 11 in Levinson, D. and Krizek, K (2008)  Planning for Place and Plexus: Metropolitan Land Use and Transport. Routledge.

Elements of Access … On Sale Now

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

Now available: Elements of Access: Transport Planning for Engineers, Transport Engineering for Planners. By David M. Levinson, Wes Marshall, Kay Axhausen. 342 pages, 164 Images (most in color). Published by the Network Design Lab.

About the Book

Nothing in cities makes sense except in the light of accessibility. 

Transport cannot be understood without reference to the location of activities (land use), and vice versa. To understand one requires understanding the other. However, for a variety of historical reasons, transport and land use are quite divorced in practice. Typical transport engineers only touch land use planning courses once at most, and only then if they attend graduate school. Land use planners understand transport the way everyone does, from the perspective of the traveler, not of the system, and are seldom exposed to transport aside from, at best, a lone course in graduate school. This text aims to bridge the chasm, helping engineers understand the elements of access that are associated not only with traffic, but also with human behavior and activity location, and helping planners understand the technology underlying transport engineering, the processes, equations, and logic that make up the transport half of the accessibility measure. It aims to help both communicate accessibility to the public.

Features & Details

  • Size 8×10 in, 21×26 cm.  340 Pages
  • Images 164 Images (most in color)
  • ISBN
    • Softcover: 9781389067617
    • Hardcover: 9781389067402

     

  • Publish Date Dec 31, 2017
  • Language English

Purchase


Table of Contents

I Introduction

1 Elemental Accessibility

  • 1.1  Isochrone
  • 1.2  Rings of Opportunity
  • 1.3  Metropolitan Average Accessibility

II The People

2 Modeling People

  • 2.1  Stages, Trips, Journeys, and Tours
  • 2.2  The Daily Schedule
  • 2.3  Coordination
  • 2.4  Diurnal Curve
  • 2.5  Travel Time
  • 2.6  Travel Time Distribution
  • 2.7  Social Interactions
  • 2.8  Activity Space
  • 2.9  Space-time Prism
  • 2.10  Choice
  • 2.11  Principle of Least Effort
  • 2.12  Capability
  • 2.13  Observation Paradox
  • 2.14  Capacity is Relative
  • 2.15  Time Perception
  • 2.16  Time, Space, & Happiness
  • 2.17  Risk Compensation

III The Places

3 The Transect

  • 3.1  Residential Density
  • 3.2  Urban Population Densities
  • 3.3  Pedestrian City
  • 3.4  Neighborhood Unit
  • 3.5  Bicycle City
  • 3.6  Bicycle Networks
  • 3.7  Transit City
  • 3.8  Walkshed
  • 3.9  Automobile City

4 Markets and Networks

  • 4.1  Serendipity and Interaction
  • 4.2  The Value of Interaction
  • 4.3  Firm-Firm Interactions
  • 4.4  Labor Markets and Labor Networks
  • 4.5  Wasteful Commute
  • 4.6  Job/Worker Balance
  • 4.7  Spatial Mismatch

IV The Plexus

5 Queueing

  • 5.1  Deterministic Queues
  • 5.2  Stochastic Queues
  • 5.3  Platooning
  • 5.4  Incidents
  • 5.5  Just-in-time

6 Traffic

  • 6.1  Flow
  • 6.2  Flow Maps
  • 6.3  Flux
  • 6.4  Traffic Density
  • 6.5  Level of Service
  • 6.6  Speed
  • 6.7  Shockwaves
  • 6.8  Ramp Metering
  • 6.9  Highway Capacity
  • 6.10  High-Occupancy
  • 6.11  Snow Business
  • 6.12  Macroscopic Fundamental Diagram
  • 6.13  Metropolitan Fundamental Diagram

7 Streets and Highways

  • 7.1  Highways
  • 7.2  Boulevards
  • 7.3  Street Furniture
  • 7.4  Signs, Signals, and Markings
  • 7.5  Junctions
  • 7.6  Conflicts
  • 7.7  Conflict Points
  • 7.8  Roundabouts
  • 7.9  Complete Streets
  • 7.10  Dedicated Spaces
  • 7.11  Shared Space
  • 7.12  Spontaneous Priority
  • 7.13  Directionality
  • 7.14  Lanes
  • 7.15  Vertical Separations
  • 7.16  Parking Capacity

8 Modalities

  • 8.1  Mode Shares
  • 8.2  First and Last Mile
  • 8.3  Park-and-Ride
  • 8.4  Line-haul
  • 8.5  Timetables
  • 8.6  Bus Bunching
  • 8.7  Fares
  • 8.8  Transit Capacity
  • 8.9  Modal Magnitudes

9 Routing

  • 9.1  Conservation
  • 9.2  Equilibrium
  • 9.3  Reliability
  • 9.4  Price of Anarchy
  • 9.5  The Braess Paradox
  • 9.6  Rationing
  • 9.7  Pricing

10 Network Topology

  • 10.1  Graph
  • 10.2  Hierarchy
  • 10.3  Degree
  • 10.4  Betweenness
  • 10.5  Clustering
  • 10.6  Meshedness
  • 10.7  Treeness
  • 10.8  Resilience
  • 10.9  Circuity

11 Geometries

  • 11.1  Grid
  • 11.2  BlockSizes
  • 11.3  Hex
  • 11.4  Ring-Radial

V The Production

12 Supply and Demand

  • 12.1  Induced Demand
  • 12.2  Induced Supply & Value Capture
  • 12.3  Cost Perception
  • 12.4  Externalities
  • 12.5  Lifecycle Costing
  • 12.6  Affordability

13 Synergies

  • 13.1  Economies of Scale
  • 13.2  Containerization
  • 13.3  Economies of Scope
  • 13.4  Network Economies
  • 13.5  Intertechnology Effects
  • 13.6  Economies of Agglomeration
  • 13.7  Economies of Amenity

VI The Progress

14 Lifecycle Dynamics

  • 14.1  Technology Substitutes for Proximity
  • 14.2  Conurbation
  • 14.3  Megaregions
  • 14.4  Path Dependence
  • 14.5  Urban Scaffolding
  • 14.6  Modularity
  • 14.7  Network Origami
  • 14.8  Volatility Begets Stability

15 Our Autonomous Future

Bibliography

The End of Traffic and the Future of Access | Spontaneous Access: Reflexions on Designing Cities and Transport | Elements of Access: Transport Planning for Engineers, Transport Engineering for Planners | A Political Economy of Access

Accessibility Analysis of Risk Severity

Recently published:

Accessibility loss by time threshold when highlighted link is removed.
Accessibility loss by time threshold when highlighted link is removed.

Abstract:

Risk severity in transportation network analysis is defined as the effects of a link or network failure on the whole system. Change accessibility (reduction in the number of jobs which can be reached) is used as an integrated indicator to reflect the severity of a link outage. The changes of accessibility before-and-after the removing of a freeway segment from the network represent its risk severity. The analysis in the Minneapolis – St. Paul (Twin Cities) region show that links near downtown Minneapolis have relative higher risk severity than those in rural area. The geographical distribution of links with the highest risk severity displays the property that these links tend to be near or at the intersection of freeways. Risk severity of these links based on the accessibility to jobs and to workers at different time thresholds and during different dayparts are also analyzed in the paper. The research finds that network structure measures: betweenness, straightness and closeness, help explain the severity of loss due to network outage.

Keywords: Accessibility, Vulnerability, Network structure, Betweenness 

On Greater Sydney’s 40-Year Plan

On a Sunday (yes a Sunday, now that is odd) the Greater Sydney Commission and Transport for NSW both released draft 40 year plans:

Since I am under contract to neither organization, I am free to give a review of the documents. I have comments prepared on the idea of the Three-City plan (dislike) and have something in the hopper on the 30-minute city (like), but am not clear whether it realisable.

The Draft Greater Sydney Region Plan is a gorgeous document, it is well-laid out, and pleasing to read. The Transport for NSW plan is much draftier, and appears to have been rushed. On the assumption that this is not staff’s fault, but rather that it was grabbed from their reluctant hands by political higher-ups who wanted a joint release, and who correctly assume that no one (i.e. only internationally-originating transport planning professors) actually reads plans, I will not pick on them for their unreadiness. The Sunday release is perhaps a tell in this regard.

My first blush comments about some remaining aspects of the Greater Sydney Region 40-year Plan are below (with the caveats that I have read the document once, have not read the previous documents, and am new to the country).

It is great to see the coordination between the agencies, and at least the idea that the transport and land use planning should be in sync.

The plan writes “Importantly, infrastructure will be sequenced to support growth and delivered concurrently with new homes and jobs.” This is good planning practice, and it is important that timing as well as end-state is considered.  Whether this is well-executed remains another matter. As they say, time will tell.

In general, most of the GSC plans seems reasonable and hard to disagree with, if somewhat vague in many cases. For instance. “Strategy 8.1 consider cultural diversity in strategic planning and engagement.” OK, I’ve considered it, now what should I do with it?

It is a 40-year plan (Well a “40-year vision and 20-year plan”). Infrastructure lasts a long time, we want to make sure we take sound, long-term decisions. Now I like the future and all, and even think visioning is a good idea, as is preserving options, but 40 years is a long time, even in something as slow moving as transport networks.

The Chronologically-Aware might note that it is already 2017, not 2016, and it is a 40 year plan for 2056. Let us not be bound by petty calendars, this is planning time. Also since it is already 2017, and it won’t be adopted for at least some time, it might wind up being a 38-year plan.

Think back to 1976, it was before the internet or mobile telephony (or even wireless phones), before widespread Cable TV or the VCR, before Personal Computers even (it was the year Apple was founded). How much of a 1976 plan’s prediction of life today would be correct?

I’d suggest very little of the difference between 1976 and the present would have been accurately estimated by most people, or even most planners, or futurists, in 1976. Certainly we imagine that road projects that were funded in 1976 were realised soon thereafter. And much hasn’t changed.

To borrow from Sting (1983, i.e. 34 years ago): People still face a

rush hour hell

packed like lemmings in shiny metal boxes,

contestants in a suicidal race,

‘… shouting above the din of  their Rice Krispies,’ living their lives of quiet desperation. Other aspects are far different. Far fewer factories ‘belch filth into the sky’ as least in the developed countries. Far fewer workplaces are ‘hindered by  picket lines,’ as the power of labour has withered. Far fewer businessmen have their own secretaries. We don’t have flying cars. We do have 280 characters.

Still, plans (or visions) can shape growth patterns, even if the forecasts of life are terribly inaccurate. Plans I am most familiar with, the New Town Plan of Columbia, Maryland (where I grew up) and the Wedges and Corridors plan of Montgomery County (where I worked for 5 years) both gave form to, and continue to shape their communities. Columbia was expected to be completed (built out with 100,000 residents) within 15 years (in fact, it was closer to 35 years, and the Town Center area still is not finished, 50 years on).

The Interstate Highway System of course was an important shaper of development patterns across the US, and enabled the rise of just-in-time production, among other things. It was expected to be done in 16 years (1972, from 1956), but wasn’t really essentially done until 1982, and officially done a decade later.

Laying a street network, like the Manhattan Grid,  is a largely irreversible process, as evidenced by the lack of change in the street grid even after catastrophic events like the London fire or San Francisco Earthquake.

The expectation of the plan is that Greater Sydney grows to 8 million over 40 years. Demographics are among the easiest things to forecast for long time periods, as people age and migrate slowly. At current rates, I don’t doubt the estimate of 8 million. This however depends on an open immigration policy, which I am not sure traditional Australia will continue to support.

I don’t see any discussion of an intercity High-Speed Rail or Very Fast Train. Yet clearly the transport agencies are considering this and making provision for it. Certainly the notion of HSR remains vague, and the details missing, but this is a 40-year plan.

Aspects of funding made me happy to read, even if they were hedged:

  1. “explore and, where appropriate, trial opportunities to share value created by the planning process and infrastructure investment (such as rail) to assist funding infrastructure” … Land Value Capture ! p. 31
  2. “investigate the potential of further user charging to support infrastructure delivery” … Road Pricing ! (though “charging” users  only shows up on 3 pages) p.31
Movement and Places Framework. Source: TfNSW and GSC
Movement and Places Framework. Source: TfNSW and GSC

The technological tsunami about to hit surface transport is acknowledged, but not dealt with. The word “autonomous” (as in Autonomous vehicles) shows up on 5 pages. Not enough thought is given to this, given the timeframe.

The Movement and Place framework (p. 39) is good, and highly reminiscent of the Hierarchy of Roads. I like the more detailed and nuanced design from Transport for London better, (TfL’s 9 cells vs.  GSC/TfNSW’s 4), but there is an argument for simplicity.

On education, the document says: “The NSW Government will spend $4.2 billion over the next four years on school buildings, which it estimates will create 32,000 more

Streets types matrix from Transport for London looking at tradeoff of Movement and Place. http://content.tfl.gov.uk/street-types-matrix.pdf
Streets types matrix from Transport for London looking at tradeoff of Movement and Place. http://content.tfl.gov.uk/street-types-matrix.pdf

student places and 1,500 new classrooms.”

This is $131,250 per student! This is $2.8M per classroom. This seems a lot, even for Sydney. (p. 40) I sure hope some of this maintenance, not just capacity expansion.

The term “Accessibility” shows up on 14 pages. This is good, and the word seems to be used correctly. This is consistent with the idea of the 30-minute city.

Under “Directions for Sustainability” (p. 122) It is great they are using metrics. I take issue with some of them …

“An efficient city
Metric: Number of precincts with low carbon initiatives

A resilient city
Metric: Number of local government areas undertaking resilience planning”

Honestly, these specific ones are terrible metrics. Particularly the first one. Just measure (or estimate) the carbon emissions, not the number of “initiatives”.  Compare with the tree canopy “Metric: Proportional increase in Greater Sydney covered by urban tree canopy”, which looks at the actual amount of tree coverage. Resilience is admittedly trickier to assess.

 

Constructing a plan is hard (in a political sense of finding something that enough people will agree to that is more than pablum, writing down a coherent set of strong ideas is actually not that difficult at this stage in history, with so many go ideas to draw from). I applaud the effort, and think it is better than the alternative. But it could be better still, and that is the reason for discussion and comment.

Access to jobs by transit increases in many U.S. metros

From the Press Release

Bus interior

Top increases in job accessibility by transit
1. Cincinnati (+ 11.23%)
2. Charlotte (+ 11.02%)
3. Orlando (+ 10.83%)
4. Seattle (+ 10.80%)
5. Providence (+ 10.65%)
6. Phoenix (+ 7.51%)
7. Riverside (+ 6.59%)
8. Milwaukee (+ 6.53%)
9. Hartford (+ 6.44%)
10. New Orleans (+ 6.18%)

Top 10 metro areas for job accessibility by transit
1. New York
2. San Francisco
3. Chicago
4. Washington
5. Los Angeles
6. Boston
7. Philadelphia
8. Seattle
9. San Jose
10. Denver

Annually updated research from the Accessibility Observatory at the University of Minnesota ranks 49 of the 50 largest (by population) metropolitan areas in the United States for connecting workers with jobs via transit.

The new rankings, part of the Access Across America national pooled-fund study that began in 2013, focus on accessibility, a measure that examines both land use and transportation systems. Accessibility measures how many destinations, such as jobs, can be reached in a given time.

Though rankings of the top 10 metro areas for job accessibility by transit remain unchanged from the previous year, new data comparing changes within each of the 49 largest U.S. metros over one year helped researchers identify the places with the greatest increases in access to jobs by transit. Cincinnati and Charlotte improved more than 11 percent. Seattle, which ranks 8th for job accessibility by transit, improved nearly 11 percent. In all, 36 of the 49 largest metros showed increases in job accessibility by transit.

“This new data makes it possible to see the change from year to year in how well a metro area is facilitating access to jobs by transit,” said Andrew Owen, director of the Observatory. “Transit is an essential transportation service for many Americans, and we directly compare the accessibility performance of America’s largest metropolitan areas.”

This year’s report—Access Across America: Transit 2016—presents detailed accessibility values for each of the 49 metropolitan areas, as well as detailed block-level color maps that illustrate the spatial patterns of accessibility within each area.

Key factors affecting the rankings for any metro area include the number of jobs available and where they are located, the availability of transit service, and population size, density, and location. Better coordination of transit service with the location of jobs and housing will improve job accessibility by transit.

The findings have a range of uses and implications. State departments of transportation, metropolitan planning organizations, and transit agencies can apply the evaluations to performance goals related to congestion, reliability, and sustainability. In addition, detailed accessibility evaluation can help in selecting between project alternatives and prioritizing investments.

The research is sponsored by the National Accessibility Evaluation Pooled-Fund Study, a multi-year effort led by the Minnesota Department of Transportation and supported by partners including the Federal Highway Administration and 11 additional state DOTs.

The Accessibility Observatory at the University of Minnesota is the nation’s leading resource for the research and application of accessibility-based transportation system evaluation. The Observatory is a program of the Center for Transportation Studies. CTS is a national leader in fostering innovation in transportation.

 

The Transit 2016 report and other Access Across America research reports for auto, walking, and soon biking, are available at access.umn.edu.

Detailed interactive color maps illustrating the jobs accessible by transit in each metro area are available on the study web page at Access Across America: Transit 2016.

Metropolitan Transport and Land Use – Planning for Place and Plexus

Now available for pre-order, with a shipping date in December if all goes well: Metropolitan Transport and Land Use.

Metropolitan Transport and Land Use: Planning for Place and Plexus by David M. Levinson and Kevin J. Krizek
Metropolitan Transport and Land Use: Planning for Place and Plexus by David M. Levinson and Kevin J. Krizek

As cities across the globe respond to rapid technological changes and political pressures, coordinated transport and land use planning is targeted as a solution and is the subject of increased interest.

Metropolitan Transport and Land Use, the second edition of Planning for Place and Plexus, provides unique and updated perspectives on metropolitan transport networks and land use planning, challenging current planning strategies, offering frameworks to understand and evaluate policy, and suggesting alternative solutions.

The book includes current and cutting edge theory, findings, and recommendations which are cleverly illustrated throughout using international examples. This revised work continues to serve as a valuable resource for students, researchers, practitioners, and policy advisors working across transport, land use, and planning.

ISBN-13: 978-1138924260

ISBN-10:1138924261

About the Author

David M. Levinson is Professor of Transport Engineering at the University of Sydney School of Civil Engineering. From 1999-2016 he taught and served as Chair of Transportation at the University of Minnesota, where this book was first crafted. He serves as the editor of the Journal of Transport and Land Use and is the author or editor of a dozen books.

Kevin J. Krizek is Professor and Director in the Program in Environmental Design at the University of Colorado Boulder. He recently served as a Visiting Professor of ‘Cycling in Changing Urban Regions’ in the Institute of Management Research at Radboud University (the Netherlands).

Spontaneous Access: Reflexions on Designing Cities and Transport – Now in print

Spontaneous Access: Reflexions on Designing Cities and Transport is now available as a high-quality color trade paperbackIt is also available in hardcover.

It remains available as an eBook on Kindle Editions  and at the iBookstore. If you have the option, I encourage you to get it on Apple’s iBooks, where it has additional features, like pop-up references and image galleries, as it was designed in ePub3.

Spontaneous Cover-Front

Table of Contents

  1. The City Spontaneous
  2. The 60-Year Line
  3. Community without dendricity
  4. The pint-of-milk test
  5. The timeless way of building networks
  6. Axioms about roads
  7. Garden streets
  8. Vitality
  9. An archipelago of walkability
  10. Filling in
  11. Leapin’ frogs
  12. The reorganization of road function
  13. Beyond the plan view
  14. Interfaces of freedom
  15. Instruments of control
  16. Shared space
  17. Winter is coming
  18. Diversity as insurance
  19. Differentiate city and country
  20. Don’t confuse the place for the time
  21. Great Britain doesn’t have an Americans with Disabilities Act
  22. Designs serve varied and sometimes conflicting interests
  23. A vision of visions
  24. A faster horse
  25. The Ant and the Grasshopper
  26. Deconstructing Busytown
  27. Spontaneity in a can, spontaneity in a plan
  28. Building the city spontaneous
  29. Framing regional development
  30. First do no harm

There are several themes in the book:

Cities and their networks operate on multiple timescales simultaneously. Traffic lights change by the second, rights-of-way last millennia. Cities see massive daily flows of people in and out. The core, timeless, enduring elements contrast with the faddish ephemera that too much effort is focused on. The future is emerging, but determining what we are looking forward to will be enduring or ephemeral should be the critical focus of anyone involved with transport and city design.

This book does not shy away from the normative and prescriptive. In this it differs from much academic work, including my own, which tends to the positive and descriptive. Principles are laid out, which I believe to be true and correct, many of which are not scientific in the way they are framed. They of course may lead to testable hypotheses, but they are also value-based.

The idea of the ‘spontaneous city,’ one that serves needs and wants in real-time, is a theme running through both the title and the text. What conditions encourage people to take advantage of their city (and therefore make it stronger)? What conditions worsen life for the users of the city?

The emergence of new transport technologies gives us a chance to restore and correct, to right what is wrong with the places we live. From the railroad and electric streetcar creating separation between places where people lived and where they worked, to the elevator enabling high rise construction, to the motorcar which put suburbanization into over- drive, all significant transport innovations reshape cities. The new autonomous vehicle, the new electric vehicle, the new shared vehicle, the vehicle form, shape, and size are a transformation of similar scale and scope. These changes will create opportunities over the coming decades, which we can seize or reject.

This book is about how cities do work, how cities can work, and how cities should work. In part it is about traditional fields of planning and engineering, but takes a much broader concept of design principles than those fields usually do. This is because it is also about evolution and it is about opportunism. The world is changing fast. We can make it a more humane place than it has ever been, or we can allow it to devolve into a more brutish environment, where we remain a victim of our collectively built environments, rather than their master.

When the book speaks of ‘cities’ it really means the entire metropolitan ‘urban system,’ not just the historic core city (or the central business district). Downtown is but a part of the city, and the central city in many metropolises is not even a plurality of residents.

Much of this book includes complaint, and it may feel like shouting into the wind. But every complaint is about a design failure, either with intention or by accident, that degrades experience for everyone, or degrades the experience of some for the benefit of others. Life is comprised of tradeoffs, but not all tradeoffs are made at the appropriate rate of exchange. Both cities and their transport networks are the product of thoughtful human actions and unconscious emergent processes, where systematic behavior drives the underlying logic of designs.

The optimal design of transport networks to serve the goal of spontaneous access cannot be determined in the absence of knowledge about the actual development pattern. The optimal development pattern cannot be known without regards to the plan of the network. Discovering the right combinations of networks, land use, and other urban features is what makes cities successful. The measure of their success is their population, their wealth, their happiness.

But even more importantly, the optimal transport network for the technology of one era is not necessarily the optimal network of the future, and the same is true for development.


Much of Spontaneous Access is drawn from my blog transportist.org, or streets.mn, although it has been significantly edited and reorganized from posts that may have appeared there. In that sense, it is a younger sibling to the recent (2015) book The End of Traffic and the Future of Transport with Kevin Krizek. It is a collection of reflexions (a somewhat archaic British way of spelling “reflections”), short essays that collectively give insight into today’s design problems and some possible solutions.

A model of two-destination choice in trip chains with GPS data

Recently published:

Studying trip chaining behavior has been a challenging endeavor which requires the support of microscopic travel data. New insights into trip chaining can be gained from real-time GPS travel data. This research introduces a framework that considers two-des- tination choice in the context of home-based trip chains. We propose and empirically compare three alternatives of building choice sets where we consider various relation- ships of the two destinations (such as major–minor destinations, selecting one first, and selecting two concurrently). Our choice set formation alternatives use survival models to determine the selection probability of a destination. Our results reveal that trip chaining behavior is shaped by the features of retail clusters, spatial patterns of clusters, trans- portation networks, and the axis of travel. This research reveals that not only the spatial relationship but also the land use relationship of the destinations in a trip chain affect the decision making process.

Justice, Exclusion, and Equity: An Analysis of 48 U.S. Metropolitan Areas

Recent working paper

Injustice in transportation services experienced by disadvantaged demographic groups account for much of these groups’ social exclusion.

HoustonOppUnfortunately, there is little agreement in the field about what theoretical foundation should be the basis of measures of the justice of transportation services, limiting the ability of transportation professionals to remedy the issues. Accordingly, there is a need for an improved measure of the justice of the distribution of transportation services, which relates to the effectiveness of transportation services for all members of disadvantaged groups rather than for only segregated members of these disadvantaged groups. To this end potential measures of distributive justice, based on the accessibility to jobs provided by various modes, are evaluated in 48 of the top 50 largest metropolitan areas in the United States. The purpose of the study is to inform recommendations for appropriate use of each measure.