Traffic Calming

Traffic calming reduces the speed and volume of motorized traffic by means of physical alterations to the street layout, street closures, speed limits, and enforcement of traffic laws. Reductions in traffic speed and volume diminish the negative effects of motor vehicles on neighborhoods and the environment. This can improve neighborhood quality of life, promote neighborhood social activity, and enhance mobility options for vulnerable groups. Moreover, having slower and fewer motor vehicles increases traffic safety—especially for pedestrians and cyclists. In addition, less traffic accidents and more walking and cycling can increase public health. Some studies also show increases in the value of adjacent property and a reduction in the need for police enforcement. Common traffic calming measures are street closures or semiclosures, [Page 422]speed humps, speed tables, and raised crosswalks. Road narrowings, zig-zag road layouts, and bulb-outs—forcing motorists to turn at low speeds—are also common. Most traffic calming measures make car traffic slower and less attractive and, combined with the right policies, can increase the attractiveness of walking and cycling.

Traffic calming measures include street closures or partial-closures, speed bumps, raised crosswalks, zigzag road layouts, bulb-outs, and road narrowings, as seen here in Worcestershire, England

Source: Benkid77/Wikipedia

Traffic calming has its origins in the Netherlands. In the late 1960s and 1970s, residents of Dutch municipalities responded to increasing cut-through traffic in their neighborhoods. They used tables, benches, sand boxes, and physical streetscape alterations to create an obstacle course for automobiles and to claim the street as living space. This newly designed type of public space was called Woonerf—which literally translates into English as “residential”’ or “living yard”—today more commonly known as “home zone.” Indeed, home zones turn streets from traffic thoroughfares into outdoor living spaces for all. Physical alterations to the streetscape give priority to pedestrians, children at play, and bicyclists over car traffic. Moreover, maximum allowable automobile travel speeds are sharply reduced—often as low as walking speed, or roughly 4 mph. In the 1970s, the home zone concept spread throughout many Dutch municipalities, leading to official adoption by the Dutch national government in the mid-1970s.

In the late 1970s, the concept also spread to other European countries and to North America. In each country the concept was adapted differently. For example, German municipalities considered the extensive alterations to the street surface in home zones as too expensive to be applied to larger areas. Thus, traffic-calmed neighborhoods in Germany include only minor alterations of the streetscape, but restrict car travel speeds to 19 mph (so-called Zone 30 areas). Since the late 1970s, most German municipalities have traffic calmed nearly all of their neighborhood streets. In large cities, such as Berlin or Munich, between 70 and 80 percent of roads have been traffic calmed. Home zones also exist in Germany but are more limited in scope than Zone 30 traffic-calming schemes.

Today, traffic calming in Northern Europe is usually area-wide and not for isolated streets. This ensures that through traffic is displaced to arterial roads and not simply shifted from one residential street to another. Denmark, Norway, and Germany (among others) also successfully applied traffic calming to nonresidential arterials and other major roads. Related to traffic calming, almost every northern European city has created extensive car-free zones in their centers—the ultimate form of traffic calming.

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