One word – Plasticity

One word - Plastics

These are based on my brief closing comments at the WSTLUR conference in Delft.

We heard at the conference from two of the keynote speakers that “The Future is Uncertain”. While I don’t know if this is more true than before, it is certainly true. The question is: “How does one deal with uncertainty?”

One word - Plastics
One word – Plastics

In the Mike Nichols film The Graduate, Dustin Hoffman’s character (Benjamin Braddock) is advised by Mr. McGuire about the future “One word – plastics“. This advice was not too bad for 1968.

Mr. McGuire: I want to say one word to you. Just one word.

Benjamin: Yes, sir.

Mr. McGuire: Are you listening?

Benjamin: Yes, I am.

Mr. McGuirePlastics.

Benjamin: Exactly how do you mean?

Mr. McGuire: There’s a great future in plastics. Think about it. Will you think about it?



I will rephrase that for the transportation and land use context: “One word – Plasticity”.

Plasticity is defined as the ability to change in response to changes in the environment. This may be good or bad (for instance, we might not want plastic deformation in structures). However, since we cannot accurately forecast, and the long-term is unpredictable, we need Transportation-Land Use designs which are adaptable – able to change function over time, and flexible – able to do many things at once.

How do we do this?

I don’t have answers, just challenges.

Now we focus on built environment, embedded infrastructure, and long-lasting constructs, which is essentially the definition of anti-plasticity.

Developing and evaluating new plastic, adaptable, and flexible designs for Transportation – Land Use systems, I believe, is the key research and policy question in our field going forward.

A Taxonomy of Modes

A Taxonomy of Modes

A Taxonomy of Modes, Click to See Full Size
A Taxonomy of Modes, Click to See Full Size

I have been playing around with this idea of a Taxonomy of Modes. What characteristics describe and differentiate modes? Every mode must differ from every other mode on at least one dimension (otherwise they would be the same mode). This is analogous to the idea of speciation in biology. The graph above is a first cut at this for surface passenger transportation. I wanted to distinguish primarily on the non-mechanical (non-propulsion) characteristics of the service first. Of course not every possible dimension is identified, and a few of the circles contain multiple modes which are otherwise obviously distinct (e.g. gondolas and subways are much the same from a transportation service perspective but for one is underground and uses a train and the other is suspended by a cable which moves it). I wanted to differentiate things that were qualitatively different rather than quantitatively different.

So the first cut is about time, is a reservation required or not (i.e. does it need some advance planning). The second cut is about time as well, is the service scheduled or dynamic. The third cut is about space, are the routes fixed or dynamic. If the route is fixed, are stops fixed (i.e. does the vehicle stop at every stop, or only when called, like a bus). Otherwise if the routes are dynamic,  things get a bit more ad-hoc, as the key question changes.

Some traditional distinctions (access mode vs. primary mode, such as walk to transit vs. drive to transit) are not distinguished here, rather that would be thought of as at least two trips, one where you walk or drive to some place (with the purpose of changing modes), and second where you take some form of transit.

(A much earlier version of this appears as Theory of Modes (2008))


I welcome comments and ideas for making this more systematic and robust.

International Symposium on Transportation Network Reliability

International Symposium on Transportation Network Reliability
Save the Date and Call for Papers
July 22-23, 2010 University of Minnesota, Minneapolis, Minnesota
The aim of the International Symposium on Transportation Network Reliability (INSTR) is to bring together researchers and professionals interested in transportation network reliability to discuss both recent research and future directions in this increasingly important field of research. The scope of the symposium includes all aspects of analysis and design to improve network reliability, including:
• user perception of unreliability
• public policy and reliability of travel times
• the valuation of reliability
• the economics of reliability
• network reliability modelling and estimation
• transport network robustness
• reliability of public transportation
• travel behaviour under uncertainty
• vehicle routing and scheduling under uncertainty
• risk evaluation and management for transportation networks
• ITS to improve network reliability
Submission of Papers
Papers will be categorized and ranked by peer reviewers. Theoretical, empirical, case-study, and policy-oriented contributions are welcome. Papers must be submitted electronically at byDecember 23, 2009 for consideration.
Key Dates
• Papers Due: December 23, 2009
• Papers selected and submitted: January 2010
• Final Papers Due (subject to acceptance): February 2010
• Early Registration Deadline: June 1, 2010
• Conference: July 22-23, 2010
More Information
Visit the INSTR Web site at
David Levinson
RP Braun/CTS Chair in Transportation
University of Minnesota
Sara Van Essendelft
Conference Coordinator
University of Minnesota
The conference is hosted by the Center for Transportation Studies at the University of Minnesota.

Announcing the Journal of Transport and Land Use

Announcing the
Journal of Transport and Land Use – ISSN 1938-7849

The Journal of Transport and Land Use is a new open-access, peer-reviewed online journal publishing original inter-disciplinary papers on the interaction of transport and land use. Domains include: engineering, planning, modeling, behavior, economics, geography, regional science, sociology, architecture and design, network science, and complex systems.

Summer 2008 issue available:


Sprawl and Accessibility
Martin Bruegmann, Professor of Art History, Architecture, and Urban Planning, University of Illinois at Chicago
(Author of Sprawl: A Compact History)

Counterpoint: Sprawl and Accessibility
Randall Crane, UCLA Department of Urban Planning
(Co-editor of the forthcoming Oxford Handbook of Urban Planning)

Cities as Organisms: Allometric Scaling of Urban Road Networks
Horacio Samaniego and Melanie E. Moses, Department of Computer Science, University of New Mexico

A Use-Based Measure of Accessibility to Linear Features to Predict Urban Trail Use
John R. Ottensmann and Greg Lindsey, Center for Urban Policy and the Environment, Indiana University-Purdue University Indianapolis

Integral Cost-Benefit Analysis of Maglev Rail Projects Under Market Imperfections
J. Paul Elhorst and Jan Oosterhaven, Department of Regional Economics, University of Groningen (Netherlands)

To learn more about the Journal of Transport and Land Use, visit or contact:
David Levinson, General Editor:
Kevin Krizek, Editor (Americas):

The Journal is housed at the University of Minnesota and sponsored by the Center for Transportation Studies.

I-35W bridge collapse – What happened on August 1st and after

One of the interesting scientific questions that emerges from the tragedy of the I-35W Bridge Collapse is how traffic responds. There are several time horizons for looking at this.
Most immediately are those who are on the link leading up to the bridge. MnDOT’s traffic cameras show the cars turning around on the freeway within seconds of the bridge collapsing, before the dust clears literally. “Video footage of the collapse from Mn/DOT traffic camera 628. 6:05 p.m., Aug. 1, shows an edited two-minute clip from a traffic camera at the south end of the bridge. Initially, the camera is pointed to the south away from the bridge. When traffic comes to a stop, the camera pans to the north where the bridge has just collapsed. (wv file)”. This is a rational response on the part of drivers who don’t know what else may collapse. As my wife says, there are two types of people “those who run towards the meteorite and those who run from it”. Survivors are those who ran from it.
Over the next few minutes and hours, word of the bridge collapse spread. My student Shanjiang Zhu has organized MnDOT’s loop detector data into a movie that shows the 15 minute traffic counts on all the loop detectors in the Twin Cities, comparing that number with the previous Wednesday’s count at the same time of day. Blue indicates lower volumes, red higher volumes. Clearly after the collapse, people heard quickly through various sources (cell phone, variable message signs, radio, etc.), and avoided large swaths of I-35W in the vicinity (which turns blue) and complementary feeder links, while competititve substitute links (Mn 100, I 35E, parts of I-94) saw an increase. We still have to compute how overall traffic volume and Vehicle Kilometers Traveled changed.
Once people were informed, on subsequent days people searched for alternatives. The alternative the first day for some was to avoid driving, but that quickly changed, and different routes became natural substitutes. A second movie compares the counts on the 15 days after the collapse with the average of the previous 8 weeks same day of week (so a Thursday is compared with the eight pre-collapse Thursdays). This illustrates the changes network wide. The
movie is available.
Finally, there may be some longer term adaptations, but we don’t have enough information only one month into the changed situation to know about this yet. With colleagues Henry Liu and Kathleen Harder, we have obtained a National Science Foundation Small Grant for Exploratory Research to look at all of these issues in some more depth.

The Elements of Vibe

What is vibe? Vibe is the vitality of street life, the feeling that there is something going on, of being where the action is. Successful places have vibe, dead places don’t. We don’t want vibe everywhere and probably can’t support it. But surely we could have more active places then we do now with a better location of activities.
We drive to places we can walk around, rather than walk around our own neighborhood, unless we happen to live in a place with vibe.
Why do we want to walk around? Because there are multiple things to do: find food, browse books, hear music, entice the intellect, stimulate the senses. This concentration of activities only happens because of the crowds around, and the crowds only gather because of the concentration. More begets more.
These are ‘economies of agglomeration’ as the economists might say or perhaps ‘network effects’. But they allow for the spontaneous walk-in business rather than the planned trip. Many businesses are unlikely to attract spontaneous walk-ins, for instance vacuum cleaner repairs, [I don’t normally walk around with a vacuum cleaner on the hope I will find a repair shop] and thus lose little by not being located in the center of action and save much on rent. Some restaurants are so good, they require a reservation, and thus there is little spill-in traffic. But other businesses, by saving on rent, are foregoing additional business.
Moreover, those businesses are denying potential spillover traffic to their would-be neighbors. It is a calculation that proprietors must do for themselves, but there is a coordination function that a good entrepreneur can serve, matching businesses that attract walk-ins with compatible stores, and maybe subsidizing (lowering the rent for) those that generate more spill-over traffic than they attract.
There are three seeds:
* A concentration of people (customers, though they need not be spending money, that helps)
* A concentration of stuff (suppliers, who need not be selling)
* An environment that encourages people to spend time doing stuff (marketplace)
People concentrate for a variety of reasons – to exploit the material resources of the earth, to have safety in numbers, to find a pool of potential mates, or simply because it is at the intersections of routes between two other places. These intersections (nodes in transportation lingo), create opportunities. In the streetcar era, people might change lines at a node, and those pedestrians would create the streetlife necessary to support new businesses. In the highway era the scale changed, and nodes are the interchanges of freeways. Businesses, and especially shopping malls, take advantage of these points of high accessibility. But the shopping mall is now clearly the destination, not a side-product of a transfer point in the same way street-car corners were.
Some further assertions about human nature:
People like pleasant climates – dry, not too hot, not too cold, clean air, not too loud.
People want to feel safe – they don’t want a car careening out of control disturbing their sidewalk café meal, they don’t want to think they will get run over crossing the street.
People are lazy – they don’t want to walk too far to get where they are going. If they are driving, they want easy convenient parking near their destination. They like to cross the street midblock and don’t want to have to walk to intersections.
People are cheap – they don’t want to pay for that easy convenient parking, they prefer lower to higher prices for the same good.
The last two be summarized by the idea that “People take the path of least resistance�?.
Observing cities around the world with an informed, but casual analysis leads me to assert some rules about the environment that lead to vibrancy.
Buildings on the sidewalk – vibrant areas have buildings that abut sidewalks with not large gaps between the building and the walk. The density of activity is necessarily reduced by space between building and path (and thus other buildings).
Sidewalks on the street – to have vibe, sidewalks must abut the street, or *be* he street in pedestrian only areas. Pedestrian only areas can work, and anyone who says otherwise has other interests at heart. This does not mean that they will work, but given the right environment, people would prefer to shop without having to look out for motorized vehicles.
Streets move slowly – fast streets make pedestrians feel unsafe, and thus reduces the benefits of being on the sidewalk. Ideally streets are moving at pedestrian speed in the pedestrian area. Of course streets leading to the pedestrian area move faster, or people could not get there.
Vehicle space on the street is minimal – wide streets increase the distance pedestrians must walk to reach other activities. Narrow streets give access to more stuff in less time. Hence the reason many enclosed shopping malls work better than many shopping streets is the density of stuff is fairly tight.
Street two way – One way streets may not be inherently problematic, but one-way streets are generally that way to move more vehicle traffic faster through the area, which is the opposite goal of moving pedestrians between buildings within the area.
Opportunities to explore just around the corner – hidden (pleasant) surprises are one of the things that make cities interesting to be in, if I go around this corner what will I discover. The same opportunities do not exist in an enclosed shopping mall, where everything is pre-mapped and tightly controlled, and I know each “block” ends at a parking ramp. Hidden unpleasant surprises however are one of the things that can kill a city, I don’t want to experience dread when I walk down an alley attached to my favorite shopping street.
This set of rules is by no means complete, but rules like these created streetlife in streetcar era places, and they create vibe in the better shopping malls. 

Journal of Transport and Land Use.

We are pleased to announce the Journal of Transport and Land Use.
What, you ask? Another journal amidst an already overcrowded field?
Yes, we respond enthusiastically! Several journals touch on the interaction of transport and land use; however, they do so peripherally. This new venue puts both transport and land use front and center. We seek to be the leading outlet for research at the interdisciplinary intersection of these two domains, including work from the domains of engineering, planning, modeling, behavior, economics, geography, regional science, sociology, architecture and design, network science, and complex systems.
The Journal of Transport and Land Use (JTLU) will be peer-reviewed, web-based, open-content, subscription-free, and free to contribute. All of this is enabled by support from the Center for Transportation Studies at the University of Minnesota, where the journal will be housed. The advantages of this new journal and new process are several:
1. With a rigorous peer-review process, only quality papers that meet scientific standards will be published within the journal.
2. By being web-based (and web-only), we reduce costs significantly compared with paper journals. Web-based publication allows a much faster turnaround time than paper publication. Our goal is six weeks between submission and first reviews returned to the author. Being web-based also allows the inclusion of full color graphics and multi-media content, and the inclusion of datasets with the publication.
3. By being open-content, papers published in JTLU can be freely distributed (with attribution), increasing the value of papers published in the journal, and increasing their likelihood of being used in course readers and being read by the public.
4. By being subscription-free, we overcome a fundamental problem of today’s expensive journals published by for-profit publishers, which many libraries can no longer subscribe to.
5. By being free-to-contribute, we overcome the burden of the open-content journals that charge the authors to publish their paper.
We are now soliciting papers covering topics at the intersection of transport and land use. Details about the journal, its editorial process, and paper submission can be found at the journal’s website .
If you are interested in organizing a special issue, please contact one of the editors.
There will be a meeting at the World Conference on Transport Research in Berkeley to discuss the journal, contact the editors for details.
We look forward to any comments, questions, or suggestions you may have.
David Levinson and Kevin Krizek
David Levinson
Richard P. Braun/CTS Chair in Transportation Engineering
Director Networks, Economics, and Urban Systems (Nexus) Research Group
University of Minnesota (612) 625-6354
Kevin J. Krizek
Associate Professor, Urban Planning & Civil Engineering
University of Minnesota (612) 625 – 7318

History of the Future

A list of predictions made in 1900 by the Ladies Home Journal (making its round in various blogs). Note the transportation predictions:
“Prediction #4: There Will Be No Street Cars in Our Large Cities. All hurry traffic will be below or high above ground when brought within city limits. In most cities it will be confined to broad subways or tunnels, well lighted and well ventilated, or to high trestles with “moving-sidewalk? stairways leading to the top. These underground or overhead streets will teem with capacious automobile passenger coaches and freight with cushioned wheels. Subways or trestles will be reserved for express trains. Cities, therefore, will be free from all noises.
Prediction #5: Trains will run two miles a minute, normally; express trains one hundred and fifty miles an hour. To go from New York to San Francisco will take a day and a night by fast express. There will be cigar-shaped electric locomotives hauling long trains of cars. Cars will, like houses, be artificially cooled. Along the railroads there will be no smoke, no cinders, because coal will neither be carried nor burned. There will be no stops for water. Passengers will travel through hot or dusty country regions with windows down.
Prediction #6: Automobiles will be cheaper than horses are today. Farmers will own automobile hay-wagons, automobile truck-wagons, plows, harrows and hay-rakes. A one-pound motor in one of these vehicles will do the work of a pair of horses or more. Children will ride in automobile sleighs in winter. Automobiles will have been substituted for every horse vehicle now known. There will be, as already exist today, automobile hearses, automobile police patrols, automobile ambulances, automobile street sweepers. The horse in harness will be as scarce, if, indeed, not even scarcer, then as the yoked ox is today.
Prediction #7: There will be air-ships, but they will not successfully compete with surface cars and water vessels for passenger or freight traffic. They will be maintained as deadly war-vessels by all military nations. Some will transport men and goods. Others will be used by scientists making observations at great heights above the earth.
Prediction #8: Aerial War-Ships and Forts on Wheels. Giant guns will shoot twenty-five miles or more, and will hurl anywhere within such a radius shells exploding and destroying whole cities. Such guns will be armed by aid of compasses when used on land or sea, and telescopes when directed from great heights. Fleets of air-ships, hiding themselves with dense, smoky mists, thrown off by themselves as they move, will float over cities, fortifications, camps or fleets. They will surprise foes below by hurling upon them deadly thunderbolts. These aerial war-ships will necessitate bomb-proof forts, protected by great steel plates over their tops as well as at their sides. Huge forts on wheels will dash across open spaces at the speed of express trains of to-day. They will make what are now known as cavalry charges. Great automobile plows will dig deep entrenchments as fast as soldiers can occupy them. Rifles will use silent cartridges. Submarine boats submerged for days will be capable of wiping a whole navy off the face of the deep. Balloons and flying machines will carry telescopes of one-hundred-mile vision with camera attachments, photographing an enemy within that radius. These photographs as distinct and large as if taken from across the street, will be lowered to the commanding officer in charge of troops below.
Prediction #22: Store Purchases by Tube. Pneumatic tubes, instead of store wagons, will deliver packages and bundles. These tubes will collect, deliver and transport mail over certain distances, perhaps for hundreds of miles. They will at first connect with the private houses of the wealthy; then with all homes. Great business establishments will extend them to stations, similar to our branch post-offices of today, whence fast automobile vehicles will distribute purchases from house to house.
Prediction #29: To England in Two Days. Fast electric ships, crossing the ocean at more than a mile a minute, will go from New York to Liverpool in two days. The bodies of these ships will be built above the waves. They will be supported upon runners, somewhat like those of the sleigh. These runners will be very buoyant. Upon their under sides will be apertures expelling jets of air. In this way a film of air will be kept between them and the water’s surface. This film, together with the small surface of the runners, will reduce friction against the waves to the smallest possible degree. Propellers turned by electricity will screw themselves through both the water beneath and the air above. Ships with cabins artificially cooled will be entirely fireproof. In storm they will dive below the water and there await fair weather.”
Of course they missed the airplane, and were optimistic about how people should deal with traffic. But number 6 about the replacement of the horse was spot on
What will 2100 look like, or are we just so cautious now that we don’t make 100 year predictions anymore?

Clash of Speeds

In the Tofflers’ new book “Revolutionary Wealth“, the discuss the “Clash of Speeds”, saying in an interview
“If you were a cop at the side of the road monitoring the speed of the cars going by, you would clock the car of business,which is always changing rapidly under competitive pressures,at 100miles per hour.But the car of education,which is supposedly preparing our young for the future,is only going 10mph.You cannot have a successful economy with that degree of de-synchronization. ”
If education is going 10mph, one might posit surface transportation itself is going 1 mph. The networks we use are perhaps the slowest of institutions to change, the roads we use today are still where we put them a decade, a century, or a millenium (or two) ago. This slow pace of change is a two-way street. If you want to make rapid change, you will be frustrated, but if you want to make lasting change, you will be rewarded.