Continuous Flow Intersections (CFI) are a new style of intersection, developed in Mexico. In the U.S., CFIs have been implemented in Louisiana, Maryland, New York, and Utah. The first CFI in Missouri was constructed in South St. Louis County, at the intersection of Route 30 and Summit Drive.

What is a CFI?

A continuous flow intersection has traffic turning left placed to the left of oncoming traffic, opposite where it is normally. This removes the conflict between on-coming traffic and traffic turning left. Vehicles turning left access the lane a few hundred feet in front of the intersection

How is this better than a traditional intersection?

Since left-turning traffic doesn't have to cross on-coming traffic, using this type of intersection will increase the amount of "green" time on the main-line route.  At the intersection in Baton Rouge, Louisiana, wait time was reduced from four minutes to less than a minute.  This type of intersection provides a comparable level of vehicle flow as that on an interstate at a fraction of the cost, and is a dramatic improvement over conventional intersections.