National Survey of Single-Point Urban Interchanges

摘要

Current trends in the design of diamond interchanges include several new configurations which are well suited to certain topographical and traffic demand constraints. Of these new types, it appears that the single-point urban interchange (SPUI) has generated the most interest. The report summarizes selected design, operational, safety, structural, and economic issues of SPUIs. As a result of the survey and evaluation process, it appears that the SPUI is a viable alternative to other diamond interchange configurations in certain situations. It is adaptable to locations where right-of-way is limited and appears to operate efficiently under traditional NEMA 8-phase control. On the other hand, it does not appear to be well-suited to continuous frontage road situations because of capacity restrictions that result from an additional signal phase.