Spacings of Unsignalized Intersections in Urban Areas – an Empirical Approach based on Operational and Safety Requirements
Integral to the application of Access Management is the road classification system. Road classification in urban areas boils down to defining the higher order mobility routes (Classes I to 3) and then managing access provision to be commensurate with the classification. These higher order routes tend to define the urban form, as they have larger road reserves, more lanes and can end up as some form of barrier. They are also crucial for the functioning of cities (provision of mobility) as they are carrying the highest numbers of vehicles and consequently the highest vehicle-kilometre of travel.
One objective of this paper is to evaluate the spacing of these higher order roads in some real world cities, in view of the ideal spacing guidelines. The existing density of higher order routes in Cape Town (South Africa) has been determined and compared (on strategic level) with four major cities in other parts of the world (Berlin, Melbourne, Dallas and Shanghai
A further objective is to investigate the consequences of access spacing guidelines on real world situations. Issues with respect to real situations experienced in Cape Town are illustrated and compared with local and international standards. An approach to implementing the ideal standards is suggested, also in view of the guidance provided in the Access Management Manual.