Category Archives: active travel

The eternal nature of transportation corridors, but reconfiguring them

This past weekend I visited the “the Eternal City,” Roma, Italy. The Romans thought that no matter what happened to the world, no matter how many other empires might rise and fall, their city would be everlasting.  Most cities have ups and downs; their transportation corridors, usually, are another story; most have eternal lives. Once a transportation corridor is cemented (pun partially intended), it has a staying power rivaled by few inventions or fabrications in the world. Some of original paths worn by the Etruscans outside my apartment in Bologna today continue to serve as main conduits of economic activity for the region. Gravity has determined the outcome of most original Roman structures, but their roads are also still widespread throughout parts of Europe, Africa and Asia. Even the canals in northern Europe, built by the Roman empire for irrigation, later helped the British pioneer the industrial revolution; these canals y are still carrying barges, albeit leisure ones. The transportation function along any corridors rarely exists in its original form. Technologies change. Types of economic activities change. Fashions change. This largely explains why you don’t see many donkeys filling the streets in Israel anymore. Outside of the nostalgic horse and carriage for tourists and weddings in Paris, there are not many of them on the streets either. The streetcars employed in hundreds of cities across the US have been torn up for car only use.

The transportation future of cities will continue to be surface-based, with cars and existing roads playing prominent roles. But over time, the nature and character of select corridors change to better serve the needs and demands for other modes. More overall space will be made available for bikes—a contentious topic but one whose writing is largely on the wall. A sticking point is where to find the space for this change, a proposition that will require altering the nature of many transportation corridors in cities.

With urban areas built up, cities largely have four options before them to find more space. They can: (a) extend in another dimension, aerially or subterranean, (b) find new right-of-way space, (c) widen existing right-of-way space.  These first three options are either technologically difficult, involve displacing people (rarely a good idea) or are prohibitively expensive.

A fourth option requires cities to reconfigure existing space by altering the use patterns along it. Changing the nature of the transportation services along a corridor. In most cases, this option involves scaling back car use in one way or another. This is analogous to taking candy away from a child (taking space away from cars). And, its trouble points are primarily political (not financial or logistical as identified in the prior solutions).

Many corridors in urban areas already have initiatives that are rethinking the role that the car has played in the past half-century. These initiatives range from charging for or banning car use during certain times, reducing capacity by removing a travel lane, reducing capacity by reducing speed (via narrower travel lanes), removing on-street parking or all together, turning a street over to other modes. These are all steps in the same direction. Cycling’s ability to realize these gains rests in its ability to better leverage these types of initiatives by downsizing existing facilities and gently expanding alternative networks. But not all roads. Just select ones.

Where is the low hanging fruit and what criteria can help cities reinvent corridors for cycling?

  1. Communities first need to identify stretches of road that have “proven” themselves from a cycling perspective. These places might connect key origin-destination pairs. They might be currently serving cyclists who are experiencing hardship conditions. Then there are two synergistic interventions.
  2. The second step is scaling back car use. Addressing the fact that high vehicular speeds are the largest culprit to unfriendly bike environments is key. Harnessing cars to speeds below 40 km/h is necessary. If a community accompany such speed limits with reductions in the widths of vehicular travel lanes–or even the removal of some of them—all the better. (Pushing such a proposal through the political process likely involves a gentle nod to address how alternative corridors might be able to better absorb some mild enhancements to vehicular capacity via intersection design, signal timing, or on-street parking modifications.)
  3. Building up cycling facilities. Designated cycling corridors, at a minimum, deserve on-street delineation of cycling routes. This might start with a marked lane, a buffered lane (with paint), a raised path, or even physical barriers from adjacent traffic. Furthermore, intersection treatments go a long way.

Transportation corridors have amazing staying power. Cities can and should work with their existing bones to further cycling; they don’t necessarily need to search endlessly for new corridors. But there is nothing to suggest that the existing roads cannot be downsized for car use or more generally, have their purpose altered along select routes.

Where to Position Cycling in the Future Transportation Context for Cities

In order to properly position cycling amidst the larger transportation context in cities, we need to know more about what that future context of cities looks like. Just as every city or community has carved their unique path leading to its current situation, pushing that vision 50 years out is likely going to yield wildly disparate futures. Each path is shaped by a unique history, set of current conditions, culture, resources (which may or may not be available), and some unforeseen advents in technology. The future of Houston (United States) will be a stark contrast to Madrid (Spain), which will in turn not resemble Shanghai (China). And, the role of cycling in each will vary considerably.

There are several phenomena to consider in these discussions. A first has to do with the nature of growth in megacities (those with more than 10 million people) versus the growth that will be absorbed by other, smaller to medium sized cities. The second has to do with the predominant morphology of future growth. Will future development be comprised of high-rises or will it likely hover around a more manageable six stories? What will be the role of infill development? Third, what type of spatial interaction patterns will likely result? Are residents going to continue to geographically expand their circles for social activities and work or will there be a return to more localized interactions? No single projection seems to be winning out.

It is helpful to consider some prevailing global conditions to inform these discussions. There are more than a few trajectories to suggest that cities are destined for outward expansion; this suggests a decreased role for the benefits of immediate geography. The ubiquitous use of information and communication technology is the largest driver in this trajectory. As people rely increasingly rely on virtual social networks, they will rely less on their local and geographically based social networks, again, spurring, long-distance travel, if they chose to travel at all. In the transportation community, we have been talking for two decades about how telecommuting and delivery services will substitute for trips to get goods (e.g., clothing, food) and to go to work. While e-commerce comprises an approximate 5% of total retail sales (in the US), it is a phenomenon that has been increasing steadily[1]—and will inevitably to do so, thereby contributing to a trend people have less concern about living closer to services.

These forces combine with a seemingly insatiable appetite—at least for Americans—in variety seeking and comparison shopping. Prices and variety of goods will continue to play a strong role in purchasing decisions. This pushes large variety stores (e.g., big boxes) to get bigger and the trips to them less often but of greater consumption. The desire for variety is not limited to work or consuming goods. It extends to services such as schools and enrichment programs. Parents are increasingly maximizing their utility for the best overall school and fit; school districts increasingly offer this option via open enrollment. This trend diminishes the role of neighborhood schools and corresponding localized travel patterns. It, in turn, increases the burden on parents or school transportation districts to shuttle children across town.

While there are some convincing signs that the car—in its current form of a relatively lumbering machine, powered by a combustible engine, and driven by a human—might not be long for this world, the car will still be here to stay. The freedom, convenience, and privacy it provides is unparalleled with too many residents wedded to the services it provides. Furthermore, transportation networks, in most cities, are surface oriented, very mature, and predominantly structured around car travel. But cars will be increasingly smaller, propelled electrically, and driven autonomously. This will in turn increase mobility patterns for children, the elderly, and the disabled. It will ease the overall process of traveling by car, therefore leading to patterns of more and long distance travel which will facilitate exurbanization. These compelling forces paint a consistent picture of outward expansion that is less concerned about localized services. It generally weakens the central pull of cities—or neighborhoods—as activity centers.

But I believe there are other and more compelling factors to suggest that cities—and more specifically the geographic pull of neighborhoods—will ultimately win out in this tension. The ills of the traditional suburban model are now well exposed. There will always be individuals seeking both access to the big city but also pastoral living conditions; but these proportions will dwindle. On the other hand, I remain unconvinced that high-rise living is the ticket to the future. Skyscapers are less environmentally benign than is often considered[2]. This is has to do with aspects of their physical construction (e.g., being resource intensive and costly, lacking natural ventilation systems) and their effects on adjoining properties. Notwithstanding their density gains and other pleas[3], skyscrapers tend to be architecturally sterile and bereft of magic to feed human’s hunger for enchantment.

Future communities will necessarily be cognizant of their energy demands and their psychological effects; medium sized cities and towns are intrinsically better scaled for future energy realities but also humans’ intrinsic desire for belonging to a unique and localized sense of place. These places will be urban in the traditional sense of the word: compact, dense, mixed-use, and composed of neighborhood centers distributed throughout. A central transportation advantage lies in the scalability of this model. A neighborhood provides a sense of identity; several neighborhoods and a commercial district make a town; many towns comprise an average-sized city; many cities will form large metro regions. There is little new to this model. Its not a nostalgic call to return to traditional ways of occupying the landscape, just one that I think has staying power.

Traffic congestion will persist—and cyclists will still need to wrestle with it and its safety elements—but its overall burden to individuals will be less. It will be a different flavor of congestion given the increased use of smaller vehicles and sensors to better facilitate traffic management. Owing to automatic cars, people will multi-task in their cars even moreso than the average Italian does while driving and talking on their cell phone. Smartphones provide real-time information to endless services, easing the process by which different transportation services might be availed to the average traveler.

Then, if we believe in the diminishing role of gas to propel cars, this erodes the gas tax—a central source of funding for roads at all levels (at least in the United States). Local municipalities, realizing the demise of federal funding, will assume heightened responsibility for surface transportation, resulting in decisions that are better informed by capital, operating and maintenance costs and more equitably distributed across a variety of travel modes. Europe already does this well. The rest of the world will catch up in such thinking.

Putting the above factors to work as a visionary, I believe the land use-transportation future for most cities—big and small—is best captured in the following depiction. They will be oriented around central tenets of walkability, still allow car travel, and connected by rail lines. These urban places will exist on a much smaller scale than what is familiar to most people in big cities today, built on a much finer grain. Specifically, cycling will provide a much needed and valued connective tissue to bond both land uses and the other three predominant modes (walking, transit, car). Residents who live in urbanized areas—which would comprise more than 60% of the world’s population—would have a wide array of travel options available to them; many of these travel modes would rival one another in attractiveness or convenience. This means that common origins and destinations would be served by one or more of the following services: private auto, light rail, heavy rail, local bus, bus rapid transit, car-sharing, bike-sharing, walking, and of course, private cycling. Certainly not all services will be ubiquitous; however, most places would have two or more attractive travel options arranged in a seamless labyrinth of sorts where redundancy between modes is encouraged to the extent that resources allow.

These conditions culminate in environments not only accepting of bicycling but also help articulate a central role for it. I’m not going so far as to suggest that cycling will be the catalyst for a 21st Century urban renaissance[4], nor will it be the predominant form of transport (outside of select communities in Northern Europe). But, its status as a fringe mode will eventually be forgotten and cycling’s future will rest in its ability to “get along” and mesh with these other modes.

[1] See report and table at:




Health tradeoffs (some of them) hitting popular press

The Atlantic Cities has a diddy exposing some of the pollution ill-effects of cycling. But, the larger question is still left open. Even considering the air pollution burden from cycling–and perhaps even the safety risks owing to crashes–is it healthy? We need to look at the larger context. The prevailing evidence, I would argue, suggests that cycling is healthy–overall–because of the physical activity benefits.

Top planning books of 2012…including the Bikeway Design Guide?

Planetizen just announced its 11th annual list of the ten best books in urban planning, design and development published for 2012. The list selected by Planetizen’s editorial staff covers a range of urgent topics. A couple of reactions:

-Popular press and journalistic authors dominate (not academics and researchers). This is to be expected, but I did not recognize a single academic. I suppose our writing style (or our findings?) really are boring.

…but, speaking of boring:

-Of the ten books listed, the 329 page Urban Bikeway Design Guide by the National Association of City Transportation Officials is one of them. Seriously? A technical manual as a “best of”? Apparently, the editorial staff is stacked w insomniacs. It is great to see a bike reference among the list. And, it is a really useful guide, don’t get me wrong. But still.

Health benefits of switching to transport and bikes

Some of the most robust research, internationally, of the health benefits derived from switching car use to other modes is coming out of the Centre for Research in Environmental Epidemiology (CREAL) in Barcelona. They have looked at the impacts of Barcelona’s bike-sharing system in the past. Their latest work is more generally about the benefits of public transport and bike. Yes, they are working with future scenarios. Yes, there are lots of assumptions embedded. But the framework and the identification of key outcomes and specific measures is good to see.

Cover imageReplacing car trips by increasing bike and public transport in the
greater Barcelona metropolitan area: A health impact assessment study
Environment International
Volume 49, 15 November 2012, Pages 100–109
Rojas et al.


Estimate the health risks and benefits of mode shifts from car to cycling and public transport in the metropolitan area of Barcelona,Spain.
We conducted a health impact assessment (HIA), creating 8 different scenarios on the replacement of short and long car trips, by public transport or/and bike. The primary outcome measure was all-cause
mortality and change in life expectancy related to two different assessments: A) the exposure of travellers to physical activity, air pollution to particulate matter < 2.5 μm (PM2.5), and road traffic fatality; and B) the exposure of general population to PM2.5, modelling by Barcelona Air-Dispersion Model. The secondary outcome was a change in emissions of carbon dioxide.
The annual health impact of a shift of 40% of the car trips, starting and ending in Barcelona City, to cycling (n = 141,690) would be for the travellers who shift modes 1.15 additional deaths from air pollution, 0.17 additional deaths from road traffic fatality and 67.46 deaths avoided from physical activity resulting in a total of 66.12 deaths avoided. Fewer deaths would be avoided annually if half of the replaced trips were shifted to public transport (43.76 deaths). The annual health impact in the Barcelona City general population (n = 1,630,494) of the 40% reduction in car trips would be 10.03 deaths avoided due to the reduction of 0.64% in exposure to PM2.5. The deaths (including travellers and general population) avoided in Barcelona City therefore would be 76.15 annually. Further health benefits would
be obtained with a shift of 40% of the car trips from the Greater Barcelona Metropolitan which either start or end in Barcelona City to public transport (40.15 deaths avoided) or public transport and
cycling (98.50 deaths avoided).The carbon dioxide reduction for shifting from car to other modes of transport (bike and public transport) in Barcelona metropolitan area was estimated to be 203,251
t/CO2 emissions per year.

Interventions to reduce car use and increase cycling and the use of public transport in metropolitan areas, like Barcelona, can produce health benefits for travellers and for the general population of the
city. Also these interventions help to reduce green house gas emissions.

  • We assess the health impacts of replacing car trips by bicycle or public transport.
  • Replacement of the car trips reduces mortality in travellers who shift the mode.
  • Replacement of the car trips also reduces mortality in residents of urban areas.
  • Replacement of car trips can reduce the emissions of CO2.

the Economist. Now on-board

The EconomistI have long considered The Economist as a somewhat reliable barometer for mostly, writing style…but also for reliable news about world events. Sure, its a bit liberal, but one could argue that writing style usually makes up for it.

They are now on-board with reporting on cycling. Though, this article, in my opinion, is lacking a bit. The usual dribble is rolled out about increases in cycling in North America; and they kind of hinge a lot on the “doubling” of the cycling population (sure, it is an increase of 100%, but it still hovers around 1%…fully within measurement error).

Still, it is refreshing to see such news reported in The Economist, I suppose.


Bike to Work Day – 30% first time participants

Most communities around the US celebrate bike to work day and week in May. The idea is to celebrate and promote the whole concept and get more people on-board. In Colorado, the Front Range communities wait until the 4th Wednesday in June. It is quite a celebration with the Regional Council (DRCOG) playing an active role. There are over 45 breakfast stations in  city of Boulder alone–that’s almost 2 stations per square mile of town.

The whole idea, it seems, is to get people to “register” for the event and thereby “pledge” to do more of it–almost 1,800 of them across the Front Range. I’m not sure I fully follow the wisdom of such, but it seems harmless. Relative to previous years, it seemed that attendance was a bit down in Boulder, likely owing to the obsessive heat for several consecutive days prior and the onset of pretty dramatic forest fires.

The ACT Research Group will be partnering with DRCOG analyzing some of the survey results. Some positive university press has already been generated. Our central research question is going to focus on those who do it this day but not the rest of the day–drilling down into the strength and duration of the “lag effect” of such an intervention. Supposedly 30% were first time participants.

CDC Expert Panel on active transportation

The Centers for Disease Control and Prevention is presently convening an Active Transportation Expert Panel for a 2-day meeting. I helped serve on the planning committee for the workshop and offered one of the presentations titled, “Measuring Active Travel: Perspectives from the Transport Field,” with some key slides below.

Further testament to the popularity of cycling: Would you choose cycling or S&%

This might be considered by some to be less germane to core notions of bicycle planning. It is interesting and related to active communities and active transport, nonetheless

People love their bikes. In a recent survey of 5000 Bicycling magazine readers, 50% of men and 58% of women said that—if pressed to choose between sex or bikes—they’d pick the bikes. Draw your own implications about the future of our cities, society in general or even the nature of relationships.