Continuous Flow


SafeRoad Solutions - Roundabouts​​


A Continuous Flow Intersection (CFI) is an effective design solution to improving traffic safety and flow at high-volume, conventional intersections. It alters the way vehicles turn left on the main road by diverting left-turning traffic into crossover lanes ahead of the main intersection.

A CFI shifts left-turning traffic to the outside edges of the road, which allows for through traffic to proceed at the same time vehicles are turning left. That means more vehicles can travel through the intersection during a green light.

Right-hand turns are a little different, too. They are offset, functioning more like a highway ramp, and exiting cars merge into the flow of traffic.

CFIs can be designed to serve motorists coming from two sides of an intersection or four, if necessary.

CFIs are also known as:

  • Displaced left-turns

When to use a CFI
CFIs are effective solutions for intersections with:
  • high and increasing traffic volume,
  • an above-average incidence of crashes, and
  • motorists who must wait through several signal phases to turn.
​CFIs have a large footprint, so they are not good for locations with limited space.  They are also not effective designs for locations with high rates of pedestrian traffic.

  • Safety —CFIs eliminate 90-degree left turns, which reduces the number of crashes such as head-on collisions or T-bones.
  • Efficiency —When compared to a conventional intersection, the CFI reduces queue wait time times by up to 26 percent and overall delays by up to 40 percent.

  • Capacity – CFIs accommodate more vehicles and so a higher volume can travel through the intersection. This is especially effective at intersections with high volumes of left-turning vehicles during daily commutes.

How to use a CFI
All vehicle traffic should follow traffic signals and signs.

Pedestrians in CFIs should follow crosswalks and directional signage.  Bicyclists may use pedestrian paths or follow the flow of traffic.

In a CFI configuration, motorists start their left turn several hundred feet before the intersection; they enter a bay that is protected (often by a landscaped traffic island or concrete barrier) instead of just marked lanes and proceed to the left of oncoming traffic.
Fact Sheet

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