Traffic calming 

Signing indicating that a motorist is approaching traffic calming devices
A median island with a raised mid-block crosswalk
A curb extension at a mid-block crosswalk
A chicane on a one-lane road
A diverter replaces a four-leg intersection with two curves
The available turning radius has been reduced at this intersection
A motorist disregarding a directional closure (a two-lane roadway with one terminus converted to one-way access)
Two traffic calming measures: speed cushions (the two reddish pads in the road) and a curb extension (marked by the black posts and white stripes)

Traffic calming is a set of strategies used by urban planners and traffic engineers which aim to slow down or reduce traffic, thereby improving safety for pedestrians and bicyclists as well as improving the environment for residents. Calming measures are common in Europe, especially Northern Europe; less so in North America.

Traffic calming was traditionally justified on the grounds of pedestrian safety and reduction of noise and local air pollution which are side effects of the traffic. However, streets have many social and recreational functions which are severely impaired by car traffic. The Livable Streets study by Donald Appleyard (circa 1977) found that residents of streets with light traffic had, on average, three more friends and twice as many acquaintances as the people on streets with heavy traffic which were otherwise similar in dimensions, income, etc. For much of the twentieth century, streets were designed by engineers who were charged only with ensuring traffic flow and not with fostering the other functions of streets. The basis for traffic calming is broadening traffic engineering to include designing for these functions.

There are 3 "E"'s that traffic engineers refer to when discussing traffic calming: engineering, (community) education, and (police) enforcement. Because neighborhood traffic management studies have shown that often it is the residents themselves who are contributing to the perceived speeding problem within the neighborhood, it is stressed that the most effective traffic calming plans will entail all three components, and that engineering measures alone will not produce satisfactory results.citation needed

A number of visual changes to roads are being made to many streets to bring about more attentive driving, reduced speeds, reduced crashes, and greater tendency to yield to pedestrians. Visual traffic calming includes lane narrowings (9-10'), road diets (reduction in lanes), use of trees next to streets, on-street parking, and buildings placed in urban fashion close to streets.

Some additional traffic calming techniques that are often used are speed humps, speed cushions, and speed tables. These devices vary in size based on the desired speed. Humps, cushions and tables slow cars to between 10 and 25 miles per hour. Most devices are made of asphalt or concrete but rubber traffic calming products are emerging as an effective alternative with several advantages.

Contents

Types of traffic-calming engineering measures

Traffic calming can include the following engineering measures:

Recent trends in North America

Traffic calming has been successfully used for decades in cities across Europe. More recently, in response to growing numbers of traffic accidents and speeding problemscitation needed, cities across North America have begun creating traffic calming programs to improve safety and liveability on residential streets. Many municipalities create asphalt or concrete measures, although preformed rubber products that are easier to install and consistently meet standardized requirements are becoming increasingly popular.

Living street

A living street (sometimes known as Home zones or by the Dutch word woonerf, as the concept originated in the Netherlands) is a street in which the needs of car drivers are secondary to the needs of users of the street as a whole; traffic calming principles are integrated into their design.

See also

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References


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Traffic calming