2.3.1 Review Planning Reports
The location of the interchange, the appropriate form of interchange, and the number of lanes on various elements of the interchange will have been determined during the planning investigation for the new road or freeway. This information may be presented in a planning report that examines options for the location of the route and recommends a preferred option. The recommended interchanges are based on a preliminary traffic analysis.
In this part of the design process the design team reviews planning reports, supporting information and plans to develop a sound understanding of the basis for the choice of alignment and conceptual interchange layout. Of particular interest are design controls and criteria that may be related to any of the aspects listed in Section 2.2.1 (e.g. topography, geology, watercourses and environment).
In some cases the planning investigations may precede the design of the road by many years and in this part of the process the traffic prediction and analysis should be revisited to confirm that the conceptual layout is still appropriate and socially and environmentally acceptable.