Single-Point Urban Interchange (SPUI)

What is a Single-Point Urban Interchange?
A Single-Point Urban Interchange (SPUI) is a type of interchange. In a SPUI (pronounced "Spooey"), a single traffic signal at the center of the interchange controls all left turns. Drivers make opposing left-turns at the same time under the protection of this signal.

What are the benefits of a SPUI?

• Can be constructed where there would not be room for a standard interchange--ideal for urban areas
• Can allow more vehicles to make a turn and clear the interchange in one traffic signal cycle
• Can be coordinated with cross-street signal systems
• Allows long, gradual turns so larger vehicles have more room to navigate

Examples of Traffic Movement Through a SPUI

• I-94 SPUI at Westnedge Avenue in Portage
• Beck Road/I-96 SPUI - View traffic diagram and the diagram of pavement markings.  You can also view a video (2.4MB) simulation of traffic moving through this interchange.

More information about SPUIs
You can find more information at these sites:

• Improve I-70, Missouri Department of Transportation
• Single_Point_Urban_Interchange, definition