Continuous flow intersection

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A continuous flow intersection (CFI), also called a crossover displaced left-turn (XDL), is an at-grade intersection that moves the turn conflict (to the left where traffic drives on the right and vice versa) out of the main intersection. A CFI moves the left-turn down the road several hundred feet eliminating the left-turn traffic light phase. The CFI is a patented design invented by Francisco Mier, of Mexico, where over 40 have been implemented over the past decade. As of March 2006, there are only three CFIs in the United States -- one in Long Island, New York, one in Baton Rouge, Louisiana (at the intersection of Airline Hwy and Siegen Lane), and one in Accokeek, Prince George's County, Maryland (at the intersection of Routes 210 and 228).

The amount of land required to implement this concept is a major reason why it is not used more often in urban areas.

[edit] Operation details

Sample continuous flow intersection implemented for north/south traffic while east/west traffic has a regular left-turn lane

Part of the delay at a regular, high-volume intersection is because of the left-turn cycle of the traffic semaphores; through-traffic must wait for the traffic turning left. The continuous flow intersection moves the left-turn conflict to the light cycle of the cross-traffic.

In the diagram to the right, while the east/west traffic is flowing through the intersection, the north/south left-turn traffic is allowed through each of the smaller intersections that are a few hundred feet from the main intersection. When the north/south through traffic is allowed through the main intersection, the north/south left-turn lanes are also allowed through the intersections. All traffic flow is controlled by traffic semaphores as at a regular intersection.

To reduce confusion regarding the left-turn lane, the left-turn lane and the straight-through lanes are usually separated by a concrete barrier or traffic island. This diagram shows the straight-through lanes offset by one lane through the intersection and are guided by lines painted through the intersection. But this is just a sample configuration; the lanes may be offset by more lanes or none at all.

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edit Types of road junctions
Interchanges (grade separated)	Cloverleaf - Diamond - Directional T - Diverging diamond Parclo - Trumpet - SPUI - Stack - Three-level diamond
Intersections (at-grade)	Box junction - Continuous flow - Crossroads - Hook turn - Jughandle - Michigan left Quadrant roadway - Roundabout - Superstreet - 3-way junction - Traffic circle