Before 1997, the intersection at 25th Avenue and N.E. 127th Street in Seattle had a problem. Over the previous three years, at least a dozen collisions had occurred there, and speeding was an increasing problem. Concerned residents contacted the Seattle Department of Transportation, whose engineers suggested the installation of a mini traffic circle as a means of slowing vehicles and improving safety.
After surveying nearby residents and finding 64% support for the idea, the 15-foot-diameter (4.5 m) traffic circle was constructed at a cost of approximately $6,000. In the three years following the traffic circle installation, there were no traffic accidents, and mid-block speeds had dropped from 31.7 miles per hour (mph) to 29.7 mph (51 to 48 km/h). It is no wonder that the city has to date installed more than 800 mini traffic circles since the first prototypes were installed in 1973. The city has also implemented a wide range of other measures to slow traffic, including curb bump-outs and narrowed streets.
Collectively, self-enforcing measures to reduce traffic speed and improve safety are referred to as
traffic calming. This article takes a look at this relatively new and quickly growing practice. While most traffic calming initiatives are the purview of transportation engineers and municipal planning officials, some also have an important role to play in private developments, including commercial office parks, universities, and residential subdivisions—projects in which architects and builders are likely to have greater involvement in roadway design.
As we frequently emphasize in the pages of EBN, no building stands alone. All are part of a larger community fabric. If one accepts this premise, it makes sense to look for opportunities to influence the quality of life in the built environments we are creating—and those opportunities extend well outside of the actual buildings. A universal constant of buildings is that people have to get to and from them, and for the vast majority of buildings in North America, that entails the automobile. This article seeks to shed light on one group of strategies to make this interface between buildings and the larger community a little more friendly.