Traffic calming is a literal translation of the German word 'Verkehrsberuhigung', the term's first published use in English being in 1985 by Carmen Hass-Klau. It is intended to slow or reduce motor-vehicle traffic in order to improve the living conditions for residents as well as to improve safety for pedestrians and cyclists. Urban planners and traffic engineers have many strategies for traffic calming. Such measures are common in Australia and Europe (especially Northern Europe), but less so in North America.
In its early development in the UK in the 1930s, traffic calming was based on the idea of residential areas protected from through traffic. Subsequently, it was mainly justified on the grounds of pedestrian safety and reduction of noise and local air pollution which are side effects of the traffic. However, it is now recognized that streets have social and recreational functions which are severely impaired by car traffic. The Livable Streets study by Donald Appleyard (1981) 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.