AARP Smart Driver

CONFLICT POINTS: INTERSECTIONS AND ROUNDABOUTS (UNIT 3) A standard four-way, two-lane intersection has 32 points of conflict ( ). A conflict point is defined as anywhere the path of two vehicles could cross. Look at the lines in the image below. Everywhere a line crosses another is a conflict point, represented by the red dots in the image. If you add a pedestrian to the intersection, there are an additional 24 potential vehicle-to-pedestrian conflict points, represented by the yellow squares ( ). Roundabouts greatly reduce the number of vehicle-to-pedestrian conflict points (8) as well as vehicle conflict points (8). OTHER ALTERNATIVE INTERSECTIONS (UNIT 3) DIVERGING DIAMOND INTERCHANGE (DDI) A modification of the diamond-type connection is the diverging diamond interchange (DDI). The difference from the standard diamond interchange is the crossing or channelizing of the traffic on the crossroad is to the left side between the ramp terminals, thus eliminating exclusive left turn lanes and traffic signals. This design scheme (on the right) has only 14 conflict points. DISPLACED LEFT TURN INTERSECTION (DLT) OR CONTINUOUS FLOW INTERSECTION (CFI) This design scheme may be found at both highway interchanges and highway intersections. The design displaces the main line left turns in advance of the intersection. Prior to the main intersection, the left turns cross the median, thus eliminating the need for traffic signals and reducing conflict points. A conventional intersection has 24 conflict points. With a DLT (on the right), there are only 16 conflict points for a 2-stage crossing. 32 Vehicle Conflict Points 8 Vehicle Conflict Points AARP 114 RESOURCES

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