Urban motorway

An urban motorway is a motorway constructed in a built-up urban area. These differ from other motorways in a number of respects. Because they serve local as well as inter-city traffic, junctions and access points are generally much closer together. Space constraints lead to tighter curves, and consequently speed limits are often lower than on rutral motorways. The economic and social effects of urban motorway construction are also significantly greater. Urban motorway construction requires the acquisition (often by compulsory purchase) and demolition of much property. This leads to a great increase in the cost of construction, and also provokes resistance to the protest. Since the 1970s, most urban motorway construction in the western world has only been achieved in the face of community opposition, procedural, legal and extra-legal in form. Many ambitious plans have been abandoned unstarted or only partially completed (as in London, Glasgow and Newcastle upon Tyne), and most city administrations now seek only incremental changes to the road infrastructure.

The city most altered by urban motorway construction is perhaps Los Angeles. Here, the building of a network of urban freeways led to the waning of the city centre as an economic and social magnet, and the development of a diffused city environment which has been characterised by planning theorists as non-place urban realm. The Edge City model described by Joel Garreau also depends on extensive urban motorways.