A Boulevard Left Turn intersection, also known as a Michigan Left Turn intersection, is a type of intersection in which some, or all left turning movements are made in a two-stage process. Vehicles first proceed straight through the main intersection, before completing a downstream U-turn and returning to the main intersection, where a right turn completes the overall turning movement. The U-turns are completed at dedicated locations and are typically controlled by a traffic signal. This arrangement removes the need for dedicated signal time for left turns at the main traffic signal by accommodating them through the downstream U-turn locations. All through and right turning movements are still permitted at the main traffic signal.
Intersections of this type are common and have performed well in other states including Michigan, Louisiana, Maryland, and North Carolina. Boulevard left turn intersections reduce delay at high-volume locations by rerouting left turning traffic to the U-turn locations. This eliminates the additional time necessary to accommodate left turns at a traditional intersection. The boulevard left intersection provides reduced delay and improved operation at high volume intersections, for a greatly reduced cost and physical footprint when compared with a grade-separated interchange. Additionally, a full boulevard left turn intersection has only 20 conflict points where crashes could occur, in comparison with 32 conflict points at a traditional intersection and removes the left turn severe right angle crash type from the primary intersection.
INDOT has several boulevard left turn intersections in various phases of project development. INDOT’s policy is to use innovative intersections, including the boulevard left turn, where appropriate to support its ongoing commitment to improve safety and operational efficiency through innovation and cost-effective investments.
This graphic shows how left turn movements from the primary and secondary roads work at a boulevard left turn intersection. (SOURCE: http://michiganhighways.org/indepth/michigan_left.html)
Resources from Other States:
Transportation Services Call Center
Indiana Department of Transportation
100 N. Senate Ave., IGCN 755
Indianapolis, IN 46204