Interchanges are a crucial component of the highway system, providing access to the local street system and accommodating development. Local traffic becomes concentrated in the vicinity of interchanges, stimulating additional development. Operational and safety problems can result when driveways and intersections on crossroads are spaced too closely to interchange terminals. Transportation agencies use access management techniques to balance the required mobility of a roadway facility with the accessibility needs of the adjacent land users. In 2004, TRB published NCHRP Synthesis 332: Access Management on Crossroads in the Vicinity of Interchanges. This report documented and compiled best available information and practices at the time. Since 2004 there have also been advances in intersection and interchange types and new resources to estimate safety and operational impacts. Synthesis 332 also identified research gaps that limit the ability of transportation professionals to successfully implement sound access management practices. Addressing these research needs and incorporating current knowledge could greatly benefit transportation professionals involved in access management decisionmaking. There is a need to compile best available current information, conduct additional research, and develop guidelines for access management in the vicinity of interchanges.
The objectives of this research are to develop (1) guidelines for access management in the vicinity of a freeway interchange and (2) text for recommended revisions to relevant manuals such the AASHTO Policy on Geometric Design for Roads and Streets, and the Highway Safety Manual. To the extent possible, the project should also include the development of new crash modification factors associated with access management decisions near interchanges.