A comprehensive approach to planning and designing urban streets

Urban street classifications have traditionally stressed the movement functions of streets (using terms such as 'distributor' and 'access' roads), making it difficult to determine the role to be assigned to functions associated with streets as destinations and places, and to balance these competing demands on street space. This has also provided little opportunity for traffic engineers, urban designers and land use planners to work together using a shared set of concepts and tools. This study sets out a new approach that addresses these limitations. It starts by developing a two dimensional street classification matrix, which can be used to assign each street segment in an urban network to a cell in the matrix, based on their mix of Link and Place street functions. This information is used to develop an urban Street Plan. The next step is to assess the performance of each street segment, in terms of a number of Link and Place indicators. The values of these indicators are benchmarked against agreed standards, to determine degrees of problems; and segments are prioritised for attention based on this information, weighted by Link and Place status and number of relevant street users. Additional information is then collected to assist in problem identification and option development. Design solutions depend on street capacity, local activities, level of demand, and Link and Place segment status, such that space allocation on two sections of street of similar width may vary considerably. These various points are illustrated from case studies in London and other parts of Europe. This approach is particularly valuable for tackling problems found on traditional urban high streets, which have both high Link and Place status. It firmly moves away from the Buchanan-inspired emphasis on the separation of Link and Place functions in an urban area, using a 'corridors and rooms' analogy, to one more in tune with the 'open plan office', where a range of Link and Place functions are accommodated within the same broad area. It also provides a fresh perspective on the debate about shared spaces. For the covering abstract see ITRD E145999