Challenge
The Displaced Left Turn (DLT), or Continuous Flow Intersection, is an alternative intersection form that is still relatively uncommon in the United States. Previous research had focused on the safety and operational benefits of the design over conventional intersection forms, but there was no single comprehensive design resource for DLTs.
Solution
Kittelson led the development of a guide providing a comprehensive synthesis of DLT planning, operations, safety, and design research and guidance to assist planners and engineers with implementing DLTs, including planning techniques, evaluation procedures for assessing safety and operational performance, multimodal design guidelines, and principles to be considered for selecting DLT intersections.
The Outcome
The guide, published in 2014, has been a critical resource for DLT planning and design. The DLT intersection is steadily becoming an attractive interim solution at congested arterial intersections in lieu of more expensive grade-separated alternatives.
