The problems with modern roundabouts

A new roundabout in Okemos, Michigan, makes a strong impression but may intimidate pedestrians and cyclists. It appears overengineered, thanks to the splitter island and the complexity of the configuration.  Courtesy of Ingham County Dept. of Transportation and Roads

Note: The following is condensed from “Roundabouts and Slow-Speed Roads” in John Massengale and Victor Dover’s new book, Street Design: The Secret to Great Cities and Towns, published by John Wiley & Sons. This article is in the January-February print issue of BCT. A review of the book is here.

Street design in our walkable cities, towns, and neighborhoods should begin and end with making places where people want to be. Ironically, many of the “Complete Streets” Americans are now building are incomplete when it comes to placemaking and beauty.

The Complete Streets movement is a much-needed policy-driven campaign that adds public transportation and bicycle lanes to streets, while leaving many of the details of how this is done to the engineer or urban designer. The legislation is good and its success around the country has been phenomenal—more than 600 jurisdictions have adopted Complete Street regulations—but the policy people involved with Complete Streets are, on the whole, not designers, and many of the designs built so far have consequently been hit-and-miss.

Too many creators of Complete Streets still give the car top priority, on a road that is first and foremost about vehicle throughput, even if the roadway is shared with bicycles and buses. That’s often appropriate in suburban environments where most people drive and few people walk. But today we have suburban-style traffic-calming techniques that don’t work for the creation or restoration of walkable places being used in towns and cities in the name of Complete Streets. As a nation, we’re still learning how to make real complete streets that promote walkability as much as traffic flow.

Not the best traffic calming example

The photo at top shows a roundabout in Okemos, Michigan, that Cleveland, Ohio’s City Planning Commission uses to illustrate traffic-calming. There are reasons why the photo is not the best choice to illustrate traffic calming in the walkable parts of Cleveland and other communities as well:

• Many cars on the road today could drive through the roundabout as designed at quite a high speed, and that’s not traffic calming. The photo shows a design that puts the flow of cars above the comfort and well-being of the pedestrian. For the pedestrian crossing an urban street, the geometry of the corner radii should force the car to slow almost to a stop.

• What differentiates the design of a modern roundabout from old designs for traffic circles is that the “splitter island” at the entrance should narrow the lane and direct the driver to the right, slowing the car. “Slowing” is relative, however.

• The traffic lanes are very wide. That’s good for speeding cars, bad for pedestrians crossing the roads, and bad for making the street a space where pedestrians feel comfortable.

• The yellow striping is visually aggressive—much more appropriate for highway traffic than urban speeds.

• The large signs can be read at fifty-five miles per hour, alerting the pedestrian that he or she is not in a pedestrian space.

• The sheer number of signs warning us of hazardous road conditions for cars also tells us we are in auto-dominated space.

• Things that people like, e.g., trees, have been removed.

• Placemaking is improved if the circle is not a perfect circle and has something more interesting to look at than dying grass.

• It is better for placemaking if the pedestrian islands are shaped for people rather than cars—rectangles rather than deformed triangles, for example.

• The curves on the outside of the traffic circle have no visual relationship to the circle at the center because the traffic engineer was thinking about moving cars rather than shaping a place. One goal should be shaping space: the simplest way to do that with circles is to make concentric circles. But the shapes don’t have to be circles. What’s important is that the shapes define and make comfortable spaces for the pedestrian as well as the car.

As a photo, the Okemos roundabout can make a good first impression, particularly when it’s seen in color. Everything is shiny and new, the design is orderly, and the gray of the asphalt goes well with the white concrete and the green grass—and, at this scale, with the white and yellow striping.

But for the pedestrian standing on a splitter island, the auto-based geometry of the island subtly tells that person that he’s standing in a place made for cars rather than humans. Add the bold striping and the bold signs, and the message is no longer subtle, even if we’re so used to auto-dominated design that we don’t consciously have that thought.

Roundabouts can be uncomfortable for inexperienced or cautious cyclists as well as for pedestrians. Pedestrians are moved away from the circle for crossings. This is because drivers approaching the circle and in the circle are usually looking to their left rather than in the direction of pedestrians crossing on their right. For the engineer, the priorities of pedestrians are secondary to the free flow of traffic.

Traffic circles and civic art

There was a time before the era of Organized Motordom when traffic circles and roundabouts served everyone. A traffic circle at De Soto Plaza in Coral Gables, Florida, has a large, stone fountain with a tall obelisk in the center. It appears to have been intended as a “shared space” when the city was designed in the 1920s, because the fountain is attractive in both meanings of the word, and it has a space around it where pedestrians may once have felt welcome to venture. A similarly attractive historic roundabout is pictured below. When a roundabout is used for beauty and placemaking rather than just as a traffic control instrument, it can be a welcome addition.

This traffic circle, Court Square Fountain, Montgomery, Alabama, has character and helps create a sense of place. Courtesy of Dover, Kohl & Partners; photo by Peter Fouts, Fouts Commercial Photography.

While modern roundabouts can be appropriate in some circumstances, they are often created where they shouldn’t be. A well-designed, modern roundabout with minimal striping and signs and a strong sense of Civic Art should be in every urban designer’s toolkit. But it should be used sparingly.
Many of the perils of monuments in the road go away if we just slow cars down when they’re in walkable areas—which has the extra benefit of letting the pedestrians live longer. A driver going twenty miles per hour doesn’t need striping, signs, splitter islands, or a fence to understand that hitting a five-ton piece of granite would be a bad idea.

Reprinted with permission of John Wiley & Sons, Inc.: John Massengale and Victor Dover, Street Design: The Secret to Great Cities and Towns, 2014.

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