Zen & The Art of Traffic Calming


Rob-DaltonIn the view of most urbanists, walkability is a measure of how healthy a city is. It essentially describes how safe and how well-planned a city is for pedestrians, which will in turn determine how often citizens interact with their city.

There are so many factors that go in to making a city walkable. The factor that I find to be the most important, in pretty much all cases, is how safe the walkways are in terms of traffic.

Traffic calming methods become incredibly important when improving an urban space.

Wait, what’s wrong with stop signs?

Conventional wisdom holds that stop signs and speed bumps are the way to calm traffic. But debunking this kind of thinking is as easy as recalling behavior at either of these implements. The abundance of rolling stops and mistaken traffic order at stop signs is as common as hurtling over speed bumps as though they aren’t even there.

If you prefer hard facts, take a look at the literature that has been released concerning the efficacy (or lack thereof) of stop signs and lights. While these tactics do protect pedestrians to an extent, they aren’t very effective at inducing safer roadways in terms of traffic flow.

The new age of traffic management is not only safer, but also more aesthetically pleasing.

Safe Pedestrian Areas: Bollards and Buffers

For truly optimized walkability, there need to be pedestrian-friendly destinations as well as pedestrian-friendly routes to get to them. Protecting pedestrian areas doesn’t need to be as unappealing as setting up chain link fences or Do Not Enter signs.

Bollards and planters are both used to make sure cars can’t access certain areas and to protect pedestrians. Bollards can be either fixed or removable, allowing for a flexible space that can be cordoned off for street fairs and other events. Buffers are areas that separate roadways from walkways. Buffers can also be used in the process of beautifying a city by turning a buffer into a planting strip of trees or flowers.


Improving Flow: Traffic Circles and Roundabouts

While roundabouts and traffic circles are proven to mitigate speeding and traffic collisions, their benefit to pedestrians and cyclists is less certain. One of the major selling points of these structures is that it manages the flow of traffic without requiring it to stop. Putting pedestrians into that equation necessitates traffic to stop to allow crossings.

While there are certainly risks to having pedestrians crossing at roundabouts, there are also many benefits in terms of increasing awareness and in managing congestion.

Visually, both traffic circles and roundabouts create amazing opportunities for beautifying natural areas or display of statues and fountains. Opportunities for local culture abound.


Changing Lanes: Diets, Chokers, and Curb Extensions

Perhaps the most challenging aspect of using traffic calming to make a place is trying to get pedestrians, cyclists, and cars to cohabitate peaceably. An important element of making roads safer and friendlier to non-vehicles is managing the size and shape of lanes. Most car-dependent people balk at the idea of reducing the flow of traffic, but it’s an effective way of mitigating speed.

Diets entail the closure of a lane in order to make more room for bike lanes and sidewalks. This necessitates a certain amount of congestion, but the measure does mean that there will be slower vehicles and therefore fewer dangers to everyone. Curb extensions work double duty, giving pedestrians extra space for protection and visibility while also slowing the speed of turning cars. Chokers are one of my favorite traffic calming measures because they’re not only effective, but also visually striking. They simply divert traffic around a small area, combining the concept of curb extension with that of road diets by narrowing a single lane by adding a small amount of extra curb.

With these methods combined, cars become less featured in a place by shifting focus to safety and walkability.

Curb Extension


For young or small cities, implementing an intelligent traffic calming system should be a matter of planning and growth. While it isn’t always easy to anticipate where businesses will set up shop or where residential areas will become most popular, city planners can design roadways in a way that makes these developments intuitive.

For larger cities, however, implementation might be a rather sizeable challenge. Challenges include not only the usual construction considerations of weather and budget, but also the additional obstacle of needing to shunt traffic to other roadways while work is being done. Especially for a populous city, denizens might not be thrilled about the prospect of losing lanes and/or speed. But these changes will benefit a community’s ethos, its longevity, and its bottom line.

Traffic calming can create an environment that will foster engagement in the community by providing safety and convenience to pedestrians and cyclists. Not only will this encourage a healthier lifestyle by allowing more walkability, but it will also protect the environment and increase the economic viability of an area. When your goal is to make an area into a “place”, there are few things more straightforward to address than traffic calming.

–Robert Dalton

Robert Dalton is a freelance writer, design specialist, and student of urbanist history. His interests lie primarily in nurturing walkable cities that encourage community involvement and sustainable economies. He lives in Portland, OR, one of the most walkable cities in the country, from which he draws inspiration every day.


Institute of Transportation Engineers, Traffic Calming Library, http://www.ite.org/traffic/
New York Department of Transportation, http://www.nyc.gov/html/dot/html/pedestrians/traffic-calming.shtml
Reliance Foundry, Bollard Wiki, http://www.reliance-foundry.com/bollard/bollard-wiki

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  1. The biggest invention we do not have yet is surfaces that are smart and light and strong enough to make people think miles beyond current construction. When we finally have these, we will no longer salivate over the prospect of incremental improvements in a car-centric universe. We will relegate the car to the periphery and create walkable communities built with flexibly-deployed modular lego-like elements with scaled down elements of intregral urban living within easy walking distance. We will have a new sense of private and common space, with much less private and much more common. And since this has not even begun to happen, this is just a tiny nudge – in hopes that that seismic reality comes sooner than later.

    • Hi Stephen, thanks so much for taking the time to read and respond! I completely agree that we’ll move away from car-centric cities in the future. In the meantime, I believe that it will be our responsibility in well-established cities to lead by example for up-and-coming communities. By making ideological and technological leaps and bounds in places like NYC and LA, we’ll make a blueprint for smaller, more rural communities to grow into- walkable, sustainable blueprints.

      • Thanks so much. I live in the center of Manhattan. And yet within a mile of me there are plenty of locales that could be used to create prototypes of a car-free future. It is only the vision that is holding us back. This century will see that vision become global.

  2. Amen! Here’s my post on intersection design, which touches on many similar themes http://stroadtoboulevard.tumblr.com/post/50839889035/intersection-design

    Narrow, wiggle and separate!

    • What a fantastic post, Neil. I’m always excited to find excellent resources- if it’s alright with you, I’d love to quote your article in a future work and explore these ideas.

  3. Tony Redington says

    Frankly many observations on roundabout–what they do and how they work–completely fail to identiy their transformative impact on urban streets and both the walking and bicycling modes. Unfortunately Rob Dalton too fails to review the literature and experience of those with roundabout development, policy, and design experience. Consider the statement “While roundabouts and traffic circles are proven to mitigate speeding and traffic collisions, their benefit to pedestrians and cyclists is less certain. ” Maybe the only things almost as certain as death and taxes is the safety of one-lane roundabouts for walkers and for cyclists one lane roundabouts safety with pathing so cyclists can choose not to take the vehicle travelway. Using the wrong illustration in this story shows a lack of appreciation of standard roundabout design practice–single lane roundabouts of the type shown where there are walkers all feature splitter islands protected by raised barriers (mostly standard curbing) so there is a median refuge. The walker/cyclist using the crossings faces traffic in one direction at a time. Not a single walker fatality at the roughly 4,000 roundabouts in place in North America betters the record so far of just two fatalities a year average for the over 30,000 French roundabouts. Yes, and the aggressive Melbourne drivers during recent five year period did not kill a single walker at their over 4,000 roundabouts. The only reason we cannot tout the performance of two-lane roundabouts comes from the fact that since 2-lane designs evolution is more pronounced, we have not had the opportunity yet to undertake walker and bicyclist statistically valid studies on current designs–the one lane studies now over a decade old from Sweden and the Netherlands on both bicycle and walking mode provide the kind of statistical material to validate the performance of one laners. Note the one North American cyclist fatality documented occurred at a large partially retrofit of a traffic circle. In regard to highway fatalities, AARP notes half of seniors–versus less than a quarter of younger folks–die in highway crashes at intersections, and it is no surprise the AARP strongly supports conversions of signals to roundabouts. Tony Redington Blog: TonyRVT.blogspot.com

    • The solution to all this roundabout incremental talk is to stop speaking about it and understand that the simple answer under our noses is mile square car free areas, that area holding the scaled-down necessities of urban existence including work, play, education and residence. So simple nobody can understand it.

      • Such large car-free areas require densities only a few cities in the U.S. are close to approaching. Even in our most dense cities, New York and Los Angeles, there are only a few successful pedestrian only areas. Pedestrian malls have been tried, failed and have been mostly removed in the US.

        • You are right. But densification is the future. And creating density is the key to economic sustainability. This has been obvious forever. We need to build communities along the mile square model and recreate ones that are not dense enough.

      • Tony Redington says

        Stephen: Car free zones may work in a few situations–and I do not oppose car constraints, like the $5.00 gas tax typical of energy dependent Western European nations, a tax which begins to reflect the costs to society of cars. But, given that, roundabouts benefit cars too, about a 90% reduction in serious/fatal injuries for car occupants, reduction of delay (really for all users), reduced motor fuel use, cuts in pollution etc. Most important roundabouts increase urban density potentials, i.e., fight sprawl because of two factors: (1) roundabouts enable walkable/bikable urban areas and (2) with both reduced delay for cars and increased capacities for cars roundabouts do regardless of taxing policy give development advantages to built up areas.

        • Your earlier note on one lane roundabouts is persuasive. My writing has for years (My background is not in planning though I studied with DOxiadis in the ’60s) has simply assumed that a fact under our noses goes ignored. We cannot advance with cars at the helm. This can be said in 100 ways. Sort of like pattern language before it was coopted by computer folk. I will not see what I have talked about in my lifetime but I feel it will come. Meanwhile the best planning has the ambivalent result of keeping the domination of the car alive. Along with gentrification, stratification, miseducation and commuting.

    • Good modern roundabout design also does not put water fountains in or near them. Pedestrians with sight impairments use hearing to determine when vehicles have stopped. Modern roundabouts are noticably quieter than standard intersections due to the reduced start-stop cycles and associated noise. Water fountains near modern roundabouts mask the remaining auto traffic sounds, greatly increasing sight-impaired pedestrians’ ability to cross.

    • The big difference is that roundabouts work. Traffic circles don’t. The fact that Rob Dalton conflates the two demonstrates that he understands neither.

  4. Anyone else catch that Mr. Dalton groups speed bumps and stop signs together as inappropriate tools for traffic calming, then only cites studies related to stop signs. The individual that ‘hurtles’ over speed humps/bumps/tables is the outlier that no engineer can design for. Correctly designed modern roadway speed humps and speed tables are the most effective speed management roadway design feature available for retofit to existing roadways.

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