What is "single-point urban interchange"

n. An interchange between a highway (free-flowing) and a street (with traffic signals) which allows traffic to proceed from either direction on each road to either direction on the other, and which is governed by only one set of traffic signals.

A single-point urban interchange (SPUI, or ), also called a single-point interchange (SPI) or single-point diamond interchange (SPDI), is a type of highway interchange. The design was created in order to help move large volumes of traffic through limited amounts of space safely and efficiently.