This paper traces the development of urban traffic planning by design. Roads were categorised into a hierarchical network and types of transport were segregated. The concept of safe urban planning was developed with the creation of the "woonerf" idea in the Netherlands in the 1970s, where pedestrians had priority over motor vehicles. The most common approach to road segregation employs three levels of traffic use: however, as the "woonerf" concept was further developed, roads were increasingly integrated with residential areas. Traffic moderation and speed modulation became planning tools in themselves. Urban network planning models broke down into four types: the Buchanan model with three road categories, the Danish with two, the 30kph model throughout the city; and an urban model which takes into account a functional view of the traffic network based on mobility and safety. For the covering abstract see ITRD E118896.
Abstract