The work is complete and the final report has been published as NCRHP Report 345, "Single Point Urban Interchange Design and Operations Analysis."

The Single Point Urban Interchange (SPUI) essentially combines two separate diamond ramp intersections into one large at-grade intersection which accommodates all interchanging vehicular movements and the through traffic. Signalization of the one major intersection simplifies coordination on the arterial. It has been reported that SPUIs can significantly increase traffic-carrying capability compared with the conventional diamond interchange.

The objectives of the research were (1) to document current practice in design and traffic operations at existing SPUIs and (2) to develop and document guidelines for the design, operation, analysis, and cost effectiveness of SPUIs.