Category Archives: behavioral change

Tracing U.S. programs and cultural challenges for bicycle planning | co-author: Ralph Buehler

I will be speaking all next week as part of the “Going Green” school/education outreach project in Germany organized by the U.S. Embassy in Berlin (locations for the talks include Berlin, Chemnitz, Nuernberg, and Munich). A central purpose is for participants to better understand the U.S. and its efforts to combat climate change via local and state level efforts, urban planning, and city development. I will be using transportation planning—with a focus on cycling—as a window through to understand American philosophies, changing currents, and future challenges. The below is an overview of some key points. Given the cross-cultural nature of this event, I recruited brilliant thinking from my colleague and German-native, Ralph Buehler of Virginia Tech. Ralph willingly agreed to be a partner-in-crime to co-author this post.

The path of US land use-transport to present day makes sustainable transport difficult

Understanding history and context are critical in order to properly position sustainable transport in the US, and in particular, heightened levels of bicycling. Globally speaking, cycling’s historic “heyday” was arguably most prominent in the U.S. in the early 1900’s. However, its trajectory in the U.S. has been largely downhill over the past 100 years[1]. Only recently (the past ~15 years or so) is there a a resurgence; some cities in the U.S. are starting to take cycling seriously.

The cumulative result of almost 70 years of land-use transport policies, plans, programs in the U.S. places cycling at an extreme disadvantage. The list of transport-specific phenomena is well-documented, and includes the usual suspects such as: (1) early mass motorization (Henry Ford and his assembly line), (2) road standards that discourage cycling, (3) vehicle taxes (gas taxes in the U.S. care comparatively low and the revenue is often earmarked for roadway construction), (4) interstate system (severing neighborhoods, penetrating cities with auto-only infrastructure, and also trumping more local planning efforts/ideals), (5) government subsidies for driving, including the mandated supply of ample free parking at most trip destinations, (6) technological attempts to make transport more sustainable (i.e., cleaner fuels will make driving ok) [2].

One more point needs to be underscored: the importance of the American single family home[3]. Low energy prices and huge subsidies for home mortgages have combined with a culture of “go west young man” (to wide open spaces) to form a residential landscape like no other[4], globally speaking. And, all over the U.S., residential, single family zoning is aggressively employed to support the primary investment of Americans[5]. Tony Downs has elaborated a bit more, suggesting five key tenets that most Americans hold dear to their heart[6]: (1) owning a detached single-family home on a spacious lot; (2) relying on private automobiles for movement; (3) working in attractively landscaped low-rise places; (4) residing in small communities with responsive and localized government; and (5) living free from the signs of poverty. Local governments in the U.S. are keen to protect these interests and they do it well (i.e., the Tiebout hypothesis).

The above factors have produced some critical “context-defining conditions” for sustainable transport:

  • travel distances are relatively longer than in Europe (space consumed by single family homes makes origins and destinations further apart),
  • abundant and free car parking makes driving really easy,
  • an aversion to behavior oriented pricing (perceived ‘free’ energy and ‘free’ roads are ingrained in American mindsets),
  • relatively high car traffic volumes with high speeds (cyclists are afraid of fast moving cars), and
  • funding that cannot be easily flexed for more sustainable purposes.

But that’s not all. The land use-transport system in the U.S. represents an extremely mature system. Changing mature systems is difficult because innovations have limited effect.[7] The type of sustainable transport infrastructure that many talk about—new rail line, a bike path, a major new development—are relatively modest interventions. They represent marginal changes within extensive, mature, and complex transportation systems in which travelers have multiple options with respect to mode and route choice. Moreover, auto dependence for most Americans makes policies that increase the cost and time of driving or reduce its convenience very unpopular.

Things are changing

The good news is that in the U.S. there is emerging evidence to suggest things are changing in these respects, ever so slightly.

  • The demand for driving is leveling off. Results from recent travel surveys suggest that American’s appetite for driving might be full and factors are behind this; at least two trends stand out: (1) young adults and retiring baby boomers are moving ‘back to the city’ to enjoy a less car dependent lifestyle (after decades of shrinkage many urban areas are growing), (2) young adults between 20 and 30 seem to be less car oriented than previous generations (lower car ownership rates, a lower share of licensed drivers, and less driving overall)[8].
  • Multimodality. Using more than one mode of transportation during a trip, day or week, is receiving lots of attention. Even though 85 percent of trips are still by car, the share of Americans who also use other modes of transport is increasing. This means that Americans still drive a lot, but they also walk, cycle or ride public transport for some trips[9].
  • Pricing schemes are trickling into U.S. culture. Inner cities are increasing the cost of car parking and decreasing its supply. New highway capacity is built using toll roads. Congestion pricing is being employed in many cities.
  • Sustainable modes have higher profile. In many cities, it is now standard practice to appropriate funds for sustainable transport in city budgets. Bicycle paths receive snowplowing treatments, zoning codes require office buildings to have bike parking or even showers for cyclists). Many cities are pursuing ‘complete street’ projects[10].

It is conceivable that even Americans are wondering what a future looks like with end of fossil fuels (notwithstanding new hype about gas and fracking). Outstanding questions and challenges now revolve around how to change transport and land-use systems in the U.S. to become more cycling friendly.

Future steps toward cycling’s redemption

With all of this as a backdrop, paving cycling’s path is difficult (the same applies to most other forms of sustainable transport such as walking or public transport). Here is a five point plan to help redeem cycling’s path with regard to the land use-transport system in American cities.

  1. Get the land uses right. American cities need to make standard travel distances for everyday travel (origins and destinations) shorter. Yes, roughly one-third of all U.S. trips are less than two kilometers, but more can be made of this.
  2. Change the nature of roads. Roads—more specifically, the space in the right of way–will be need to adapted to better support cycling. The “green lane project[11] is a good testament to this, but taking space from cars takes political fortitude.
  3. Build more bicycle facilities. All types of bicycle facilities would be welcome and needed, particularly physically separated paths (e.g., see greenlane project).
  4. Share space better. Making central cities similar to one-grand shared space is concept that is largely unheard of in the U.S. Space is not shared[12] and drivers are immune to wanting to share unmarked space.
  5. Keep speeds down. Not only are traffic volumes high—speeds are too—making it more difficult to attract cyclists. Traffic calming neighborhoods, city centers, and other areas (together with stricter attention to speed limits) makes these areas safer and more livable.

[1] History of cycling in the U.S., see:

[2] For a succinct description of 9 factors for why the U.S. is so auto-dependent, see:

[3] Germany less than half of the all Germans live in single-family homes, and less than a third live in detached single-family dwellings, while this percentage is double in the U.S.

[4] A key cultural difference stems from the general attitude toward building anything. In the US, the principle is that you are allowed to build something. Zoning can influence what can be built, but if it reduces the value of the land, the land owner is entitled to compensation. This is generally the opposite in Europe. One is not allowed to build anything, unless it is explicitly allowed. This tilts the European playing field in favor of less sprawl and less greenfield development, as most of the land is zoned as agricultural or natural uses only. Any change takes a long and unpredictable process with coordination with higher levels of government. Lack of planning and coordination still exists in most European countries—producing sprawl and greenfield development—but to a lesser extent.

[5] Hirt, Sonia. “Home, Sweet Home American Residential Zoning in Comparative Perspective.” Journal of Planning Education and Research 33, no. 3 (2013): 292-309.

[6] Downs, Anthony (1994). New Visions for Metropolitan America. Brookings.

[7] Another big difference stems from the general attitude toward building anything. In the US, the principle is that you are allowed to build something. Zoning can influence what can be built, but if it reduces the value of the land, the land owner is entitled to compensation. In Europe, the principle is generally the opposite. You are not allowed to build anything, unless it is explicitly allowed. This tilts the European playing field in favor of less sprawl and less greenfield development, as most of the land is zoned as agricultural or natural uses only. Any change in that takes a long and unpredictable process with coordination with higher levels of government. Of course, there is still a lack of planning and coordination in most European countries and sprawl and greenfield development do happen in Europe as well; however, the scale is different.

[8] Tobias Kuhnimhof, Ralph Buehler, Matthias Wirtz, and Dominika Kalinowska (2012). Travel trends among young adults in Germany: increasing multimodality and declining car use for men. Journal of Transport Geography 24 (2012) 443–450.


[10] Slotterback, C.S., and C. Zerger. 2013. Complete Streets from Policy to Project: The Planning and Implementation of Complete Streets at Multiple Scales. Minneapolis, MN: Humphrey School of Public Affairs, University of Minnesota.

[11] Greenlane project, see:

[12] Concept of space, See John Grisham’s, The Broker (2005) where Luigi explains to Marco some of the peculiarities of Italian culture: “…the concept of space in Europe…differs significantly from that in the States. Space is shared in Europe, not protected. Tables are shared, the air evidently is shared because smoking bothers no one. Cars, houses, buses, apartments, cafes—so many important aspects of life are smaller, thus more cramped, thus more willingly shared. It’s not offensive to go nose to nose with an acquaintance during routine conversation because no space is being violated. Talk with your hand, hug, embrace, even kiss at times. Even for a friendly people, such familiarity was difficult for Americans to understand.”

Why reduced congestion is a weak argument for cycling

In 1991 the City of Münster (Germany) aimed to raise support for the city’s spending on bicycling infrastructure. The press office of the city made a poster comprised of three panels. Each panel’s background displayed Münster’s Prinzipalmarkt, the cobblestoned main street in town; what differed in each panel was what filled the Prinzipalmarkt. The first depicted what the street looked like if 72 people were transported by car; the second, by bus; the third by bike. The main point was that bicycling is an extremely efficient way to use limited transport space in cities.

Twenty years later, Indian-based organization, Earthian, posted the figure to Facebook. It quickly went viral[1]. The graphic has since been used prominently in presentations worldwide to advance the arguments that bicycling is a strategic means of transport; bicycling can help reduce traffic congestion. In theory, it makes sense. And, the “reduced congestion” argument is one of the more prevalent ones in the advocate’s arsenal. It carries water for places with exceptionally high cycling use or for specific corridors. The argument, however, is fatally flawed when applied to larger units of geography.

The source of the substitution

The implicit assumption in the reduced congestion argument is that there is a substitution effect between a cycling trip and a vehicle trip. If true, it is helpful to consider the source of the substitution and its magnitude. For example, using mode share figures based on the US, a starting point suggests bicycling would draw from other modes in proportion to their current mode shares[2]. Bicyclists would therefore draw roughly 85 percent of their market from driving trips (solo or with others), 10 percent from walking trips, and the remaining from transit or other[3]. If most converters would come from existing transit users, a reasonably safe assumption but a population whose travel comprises a meager two percent of travel (again, in the US), then these numbers are relatively small. Tapping into the mindset of converting auto users presents a greater challenge.

The magnitude of the substitution

Understanding the magnitude of the substitution effect is difficult mainly because it is based on a counterfactual condition (e.g., if Booth would not have killed Lincoln, then…). There are two ways to think about it. One can start with a fixed number of vehicle trips and assume a share of those trips that are replaced by bicycling. Alternatively, one can consider the number of bicycle trips and estimate the share of these trips that replace driving. The two analysis strategies are not comparable.

Our own work found a wide range using the later approach, ranging between 25 and 68 percent of bike trips claiming to substitute for car trips[4]. This suggests that half of the existing bike trips, were they not by bicycle, would be by car. Such rates of substitution, I presume, vary wildly across the globe. Then think about places where cycling comprises more than half of all trips: Groningen (the Netherlands), Münster (Germany) or Copenhagen (Denmark). It is hard to conceive of the character of these iconic bike-friendly cities if most trips were by car. Most bike trips substitute and the congestion savings is remarkable. But outside of these select settings, it is hard to know. In the rest of the world, if the logic is applied to a particular corridor, the congestion savings argument might have a noticeable impact.

Vehicular travel is not fixed

For most cities, there is a there is an inherent fatal flaw with the foundations of the above logic. These flaws become apparent when congestion is considered on a larger scale or for places that are growing (the birth rates in the above mentioned towns are not exactly skyrocketing). The foundation assumes a fixed demand for travel, and vehicular travel in particular. Prevailing trends of population growth and auto ownership suggest otherwise. Coupled with what is generally known about travel behavior, and driver behavior more specifically, these factors paint a meager picture for cycling’s ability to address congestion.

Traffic congestion is a problem is that is both old and complex. Rome struggled with it, resulting in Caesar simply issuing a ban on carts and chariots back in the day. Things aren’t that easy in most cities and more recent thinking has focused on its source and solutions. A good portion of that thinking is framed around issues of capacity: building more roads or widening existing roads and what is referred to as the effects of induced demand[5]. Any form of relief provided for drivers, the story goes, will quickly be gobbled up[6]. Drivers will defect to the corridor where the relief is offered. Other drivers, previously sleeping in and starting their commute at 9:30 will join the 8:00 am rage. Still others who were previously carpooling or using transit, learning that their route is as bad as it used to be, will switch to driving. Add traffic from the inevitable new development down the street and any immediate gains become a wash.

A key outcome from most of this thinking has been coined the “Iron Law of Congestion,” suggesting that once congestion has reared its ugly head in a city, there is little the city can do get rid of it. Congestion is largely an inescapable condition in all large and growing metropolitan areas across the world.

The same logic applies to gains from getting more people on bikes; it might provide temporary respite which would be gobbled. Suppose a community cycling initiative can leverage the previously explained phenomena to the fullest. Transit users and car users alike convert to bike travel for most trips. Getting more people on bikes might mean less people driving cars; it might mean temporary relief in the previously congested corridor. But using the Iron Law and considered across the region, the effects on congestion would be futile.

Congestion is less about capacity

But that’s not all. Driver behavior is also a culprit to congestion. Tom Vanderbilt’s book, Traffic, climbed its way to become a top ten best seller on the New York Times list in August 2008. It is the only book focused on transport that has claimed such a coveted spot. One of Vanderbilt’s principle claims is that traffic congestion has more to do with driver behavior than capacity issues. Drivers switch lanes, rubberneck, merge too early or overcompensate when braking—all relatively small flaws in driving behavior—but in the aggregate, they have a major impact on congestion.

Such driver errors and their consequences on congestion will diminish over time; automated vehicles will likely clean up such mishaps. However, this stream of thought suggests congestion has less to do with overall capacity in general. Even further evidence of the importance of the operations of a system in terms of congestion comes from New York City’ recent experience. Over the past years, the city has been aggressively reallocating select street space for cyclists and pedestrians, thereby decreasing overall vehicular capacity. Analyzing taxi cab logs, however, the Bloomberg administration contends that travel speeds have remained steady despite such decreased real estate—an outcome that is largely attributed to improvements to the city’s traffic signal system[7].

Larger fish

Cycling’s limits to reduce congestion is perhaps best understood when the argument is taken to an extreme. Scaling up to large and quickly growing cities, the latent demand ready to consume any relief to existing congestion is overpowering. Projections from the United Nations paint a picture of adding more than one million people to the earth every five days for the next dozen years[8]. Admittedly, the majority of this growth will be absorbed in cities of developing countries and its impact being unequally distributed and perhaps even barely felt in Europe. But with rising incomes generally across the globe, the more than 60 million cars that are produced each year (more than 100 new cars every minute) will likely find willing drivers[9]. The primary drivers to congestion (pun intended) are more powerful than anything that bicycling can realistically impact over the next decade or two, globally speaking.

There might be good reasons to spur bicycling and build more facilities to do it. The congestion relief might be felt locally. Aiming to reduce congestion on a regional level, however, is one of the least reliable rationales for doing so. Cyclists are better off making hay from other, more reliable arguments.


[2] Transport econometricians refer to this as the principle of Independence from Irrelevant Alternatives (IIA)

[3] Summary of Travel Trends: 2009 National Household Travel Survey,

[4] Piatkowski, Dan, Kevin J. Krizek, and Susan Handy (2013). Accounting for the Short Term Substitution Effects of Walking and Cycling in Sustainable Transportation. Working paper available from the Active Communities / Transport (ACT) Research Group.

[5] Most of the original research is attributed to David Lewis [(1977), Estimating the influence of public policy on road traffic levels in greater London. J. Transport Econ. Policy, 11, pp. 155–168] and Martin Mogridge [(1990),Travel in towns: jam yesterday, jam today and jam tomorrow? Macmillan Press, London].

[6] Anthony Downs is largely credited with popularizing some of predominant thinking, starting with his 1992 book, Stuck in Traffic: Coping with Peak-Hour Traffic Congestion (1992), The Brookings Institution: Washington, DC. The concept is better explained in his updated work a decade later, Still Stuck in Traffic (2004), The Brookings Institution: Washington D.C.

[7] See, for example, or other reports such as the “Green Light for Midtown Evaluation” (January 2010), from:

[8] Population Division, United Nations, Department of Economic and Social Affairs. World Population Prospects: The 2012 Revision.

[9] Figures provided by the International Organization of Motor Vehicle Manufacturers, see:

A new form of cycling treatment?

Throughout my travels, I have seen many different style of treatments for cycling and pedestrian environments (e.g., ramps on stairs, raised paths to indicate cycle tracks, diverters to slow down bike traffic at busy intersections). While each country has their own flavor of treatments, most are pretty self-explanatory about what they are trying to accomplish.


However, in Bologna today, I saw one that mostly stumped me (see pic). Cycling is permitted on this stretch (as indicated by the paint on the pavement), but what they trying to accomplish/communicate with the track for the bike? My guess is that they want to slow down the bike speeds. But, apparently the gates alone are insufficient?


The future of cities, some reflections on reflections from Kunstler

James Kunstler’s first book, The Geography of Nowhere, was a strong force in exciting my interest in city planning. But the more I learned about the nature of cities and their dynamics, the more I saw through his journalistic view of the world. His ideas are persuasively presented, but typically barren of justifications and evidence. That is fine. He is a journalist and I am an academic.

This more recent essay from Kunstler (now two years old) is not all bad, however. He weaves together a variety of drivers on which to base a coherent and persuasive vision for the future of cities. I appreciate where he ends up. Though, there are more than a few outstanding questions:

-Are skyscrapers really not environmental?

-What about the semi-reliable predictions that the future of global population growth will reside in the equivalent of 10 new megacities of 10 million inhabitants each year for the next 20 years.

-Is there available real estate to develop at only the suggested 6 story level for such gargantuan growth? I have not run the numbers but I suggest not.

-A central premise of his arguments rests on the decline of cheap oil and water. Will this really be the case in 30 years? Have we not been hearing of such for the past 30 years? And, if it does become more scarce, who is to say that government subsidies–or lack of taxes–won’t diminish the impact.

-And, I certainly don’t get the impression that Harvard GSD is anti-new urbanism. Maybe I am missing something (again).

Infographics and gamification

The following infographic from Active Living Research recently came across my email. It is nicely presented; it is a fair representation of some of the research.  But……

…while it might satisfy some central purposes of an infographic, we have argued elsewhere, it is best to to consider the balance of the research and not rely on what one study here or there has to offer about a particular factoid.

Illustration of points for completing sustainable activitiesThe larger issue is that based on an article in the recent issue of ensia, knowledge and information have little to do with behavior change. Moral suasion does not work either (my favorite quote from the article: “If educating people about an issue would solve the problem, we would have no obesity and no smokers in our country”).

Two reactions: First, competition (what they call “gamification”) and peer pressure are paramount. We are getting there with the both–in terms of cycling, at least–but these elements take time to engender in society. Second, talk is cheap. Most everyone says they want to save water and the planet; action is less so.


Cyclists defensive about the pollution they emit

Cyclists recently came out in hoards to repel the comments from the Washington State politician who claimed, “Since CO2 is deemed to be a greenhouse gas and a pollutant, bicyclists are actually polluting when they ride.” Both the Seattle times and Velonews picked it up. And, the politician has since apologized.

It reminds me of the GM ad telling college students to stop pedaling and to start driving–an ad that was met with so much opposition that it was pulled by GM back in the fall of 2011.

** And just fyi, here are two “journalistic reporting stats” that appeared in the Seattle Times report: (1) On average, cars emit about three-quarters of a pound of carbon dioxide per mile, while bicycling releases just over 1 ounce per mile, including manufacturing, according to analysis by the European Cyclists Federation. and (2) food calories burned by a rider may well be equivalent to 650 miles per gallon, figures Todd Litman, of the Victoria Transport Policy Institute.

Leopold leadership program fellows announced for 2013

The Leopold Leadership Program Based at the Stanford Woods Institute for the Environment, the Leopold Leadership Program provides academic environmental researchers with skills and approaches for communicating and working with partners in NGOs, business, government and communities to integrate science into decision‐making.

The Leopold program just released the list of 20 individuals receiving fellowships in 2013 and I am fortunate to be a part of this crew and the first planner to boot. Read more here and from CU.

Stop being an S O V

Welcome SOV's
I am listening to the radio. The holiday advertisements are rolling. Then a new ad rolls out. It is quick, pithy, and pointed. It draws our attention to the environmental and other costs of driving. Then it jumps right to urging you not to be an SOV (single occupancy vehicle).

The tagline is edgy, no doubt. It is surprising. It catches you (or at least, me) off-guard. I thought: who really is behind paying for the creativity of such much less the air-time. As it turns out, it is sponsored by a partnership led by Denver the Regional Council of Governments.

The campaign is clearly playing to the moral suasion argument—a strategy I have suggested that, in the past, has had very little success in the past in triggering behavioral change. I guess we can keep trying. Maybe more “edgy awareness” will help.


The helmetless debate ensues, this time in the NYTimes

Where should we come down on this matter? Here is what I want to know:

(1) Where helmetless behavior reigns strong, what is the average speed of the cyclist?

(2) Where helmetless behavior reigns strong, what is the average speed of the auto?

Nothing ever talks about these matters. I imagine both are substantially slower than in most US settings. Here’s a proposition: bring down the speeds of both and helmetless behavior might not be such a big deal.