Reversible lane systems: synthesis of practice

Reversible roadways have been used throughout the world to mitigate the effects of congestion and optimize roadway performance for more than 70 years. They have been applied on a variety of roadway types using many different methods of control to address an assortment of needs, including the movement of unbalanced directional traffic associated peak commuter periods, emergency evacuations, roadway construction work zones, and other major gatherings and events. Despite the long and varied history of reversible roadways there are a limited amount of established guidelines and standards to guide their planning, design, and operation. To overcome this lack of information the National Cooperative Highway Research Program (NCHRP) sponsored a project to investigate and document reversible roadway practices to better understand the conditions that warrant their use, their impacts on safety, operations, and the environment, and their design and implementation requirements. This paper builds upon the findings of NCHRP Synthesis 340 by highlighting and summarizing the range of reversible roadway applications and discussing how the variety of reversible roadway applications have been able to address problems despite the fact there is little standardized practices to guide their implementation or assure uniformity in their use.