Highway-urban planning. Some keys of the historical evolution of an imperfect relation

Abstract

The article reviews the evolution on the highway design criteria from the first roads built before the automobile age till the modern access controlled motorways. The effects of the roads are very diverse, timevarying and different for each type of road. If before the advent of automobile roads used to have small-scale effects, the new mode of locomotion would revolutionize its role in the territory. The accessibility became a key factor and, as a consequence, road adjacent land were colonised by urban activities and buildings (ribbon development). In this context, first proposals aimed at managing roads and adjacent uses appeared: Benton’s Mackay Townless Highway and Hilarion Gonzalez del Castillo’s Colonising Highway.
With the unstoppable growth of the automobile and the evolution of the highway techniques, its design became an activity exclusive of traffic engineers, as modern movement urbanism segregated such infrastructures from urban developments. The motorways where introduced in the existing cities trough the construction of expressways and by converting green boulevards into high-capacity urban streets. At present, new highways tend to move away from populated areas, trying to escape from being involved in their growth. On the other hand, urban planners tend to regard them as limits or targets to achieve, by integrating them into the planning schemes. In this way, design decisions taken by road engineers become urban law.