Technical Procedures for Interchange Justification

Rapid land development and the lack of adequate local streets often results in requests for access to Interstate and other limited access highways. Gaining access to an Interstate highway is a highly valued asset and is aggressively pursued by local development interests. Land access demands compete with operational needs for acceptable traffic service and adversarial proceedings often result. Requests for additional access normally require investigation and preparation of technical justification studies and summary documents examining engineering, operational, and cost‐benefit factors. A major requirement for this process is a traffic study sufficient to show the impact of the proposed interchange upon current and future service levels of the mainline facility. Traffic investigations should show the impacts of major changes in land‐use surrounding the new interchanges. Established operational and geometric design policy for interchange spacing is important. Local planning requirements also affect the decision. This paper presents guidelines and procedures for the necessary studies and reports supporting a timely decision regarding the request.