Single-Point Urban Interchanges (SPUI), also known as single-point diamond interchanges (SPDI), reduce conflict points and traffic signal phases at an intersection by allowing opposing left-turn movements to proceed simultaneously without directly crossing paths of travel. This increases the capacity of the traffic signal by allowing more vehicles to clear the intersection in one signal cycle. SPUIs improve travel time and safety by having the turning movements of the major road ramps and the minor road executed at one central intersection rather than one on either side of the interchange. They are efficient where balanced left-turn volumes are present at an interchange. A SPUI can be advantageous along a corridor of closely-spaced signalized intersections.

See and below for an example SPUI and the corresponding left-turn and U-turn movements accommodated by a SPUI. Refer to the on TxDOT.gov for additional information.