Use of Freeway Shoulders for Travel — Guide for Planning, Evaluating, and Designing Part-Time Shoulder Use as a Traffic Management Strategy
Part-time shoulder use is a transportation system management and operation (TSM&O) strategy that allows use of the left or right shoulders as travel lanes during some, but not all, hours of the day. Use of the shoulder is typically restricted to certain classes of vehicles. It is one possible strategy for addressing congestion and reliability issues within the transportation system, and can be particularly cost-effective where other alternatives to add lanes are infeasible or cost-prohibitive. In such situations, TSM&O alternatives, including part-time shoulder use, may be most appropriate for cost-effectively reducing delays and improving travel-time reliability. Part-time shoulder use is most cost-effective in constrained right-of-way conditions; however, there are certain minimum geometric clearances, visibility, and pavement requirements that must be considered before part-time shoulder use can be implemented.
Purpose, Scope, and Target Audience
The purpose of this guide is to provide guidance for planning, designing, implementing, and operating part-time shoulder use. This guide provides guidance on factors that need to be considered in:
This guidance does not address the “part-time” use of a shoulder in work zones during construction (e.g., as part of a lane shift or lane closure), nor does it include the permanent, full- time “conversion” of a shoulder into a travel lane. Full-time conversion of the shoulder constitutes the “permanent elimination” of the shoulder and needs to be addressed in that context. This guide does not address pedestrian and bicycle considerations because it is focused on freeway applications. Part-time shoulder use on other types of roadways in the U.S. has been limited to bus-only shoulder use on a handful of arterials, and this guide presents only limited arterial-specific considerations.
The target audience for this guide consists of State Department of Transportation (DOT), toll agency, and Metropolitan Planning Organization (MPO) planners and designers.
Organization of Guide
The guide is organized in the typical sequence of steps required to plan, design, implement, and operate part-time shoulder use. Part I of this guide addresses the planning steps for considering part-time shoulder use.
Part II of this guide provides guidance on how to analyze part-time shoulder use.
Part III of this guide provides information on how to design, implement, and operate part-time shoulder use once a decision to use it has been made.
The appendices provide example applications of the guidance, along with case studies of successful applications of part-time shoulder use in the United States.
United States Department of Transportation - Federal Highway Administration