<P> Welwyn Garden City, also in Hertfordshire was also built on Howard's principles . His successor as chairman of the Garden City Association was Sir Frederic Osborn, who extended the movement to regional planning . </P> <P> The principles of the garden city were soon applied to the planning of city suburbs . The first such project was the Hampstead Garden Suburb founded by Henrietta Barnett and planned by Parker and Unwin . The scheme's utopian ideals were that it should be open to all classes of people with free access to woods and gardens and that the housing should be of low density with wide, tree - lined roads . </P> <P> In North America, the Garden City movement was also popular, and evolved into the "Neighbourhood Unit" form of development . In the early 1900s, as cars were introduced to city streets for the first time, residents became increasingly concerned with the number of pedestrians being injured by car traffic . The response, seen first in Radburn, New Jersey, was the Neighbourhood Unit - style development, which oriented houses toward a common public path instead of the street . The neighbourhood is distinctively organised around a school, with the intention of providing children a safe way to walk to school . </P> <P> Urban planning became professionalised at this period, with input from utopian visionaries as well as from the practical minded infrastructure engineers and local councillors combining to produce new design templates for political consideration . The Town and Country Planning Association was founded in 1899 and the first academic course on urban planning was offered by the University of Liverpool in 1909 . </P>

Urban areas that developed by the 16th century with trade central to city design were called