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MANAGED LANES: A Cross-Cutting Study

Chapter One. Introduction

Scope and Purpose

This cross-cutting study was developed to document the successful practices used in managed lane projects in operation, to identify gaps between the state-of-the-practice and the state-of-the-art, and to highlight emerging issues. The intent of the report is to provide a study of the cross-cutting issues and experiences of various agencies as managed lane projects are implemented and policies are drafted.

The intended audience for this report is transportation professionals who are involved with developing and operating managed lane facilities in freeway corridors. It is anticipated that the information provided in this document will offer valuable insight for professionals who want a basic understanding of issues associated with developing managed lane projects. Secondarily, it will serve to identify critical research and development needs related to managed lanes.

Defining Managed Lanes


The term "managed lanes" has different meanings to different agencies. In some agencies the term is commonly thought of as high-occupancy toll (HOT) lanes. In other agencies a broader definition is customary, one in which a variety of management tools and techniques are combined in order to improve freeway efficiency and meet certain corridor and community objectives. This broader definition of "managed lanes" includes HOV lanes, value priced lanes (including HOT lanes), and exclusive or special use lanes (such as express, bus-only, or truck-only lanes).

Exhibit 1 is a diagram that captures the potential lane management applications that fall into this broad definition of "managed lanes". On the left of the diagram are the applications of a single operational strategy — pricing, vehicle eligibility, or access control - and on the right are the more complicated managed lane facilities that blend more than one of these strategies. The multifaceted facilities on the far right of the diagram are those that incorporate or blend multiple lane management strategies.

Exhibit 1. Lane Management Strategy Complexity
Exhibit 1. Lane Management Strategy Complexity

The common themes among the different managed lane definitions in use today are as follows:

For the purposes of this study, the following definition of managed lanes was developed:

"Managed Lanes" are defined as a limited number of lanes set aside within an expressway cross section where multiple operational strategies are utilized, and actively adjusted as needed, for the purpose of achieving pre-defined performance objectives.


Major metropolitan areas are facing increasing traffic congestion that costs billions of dollars every year in lost productivity, wasted fuel, and hours of delay. In FY 1999 the nation lost an estimated $ 72 billion dollars due to this waste (1). Congestion is growing over the entire highway system but its effects are most profound in urban areas. These areas are also struggling to rebuild a system that has outlived its design life.

Compounding this problem, Americans are driving more now than ever before. Vehicle travel has increased more than 70 percent in the last 20 years while highway capacity has only increased by 0.3 percent each year for the last decade (1). Growing traffic congestion is not only impacting the traveling public it is also having a serious effect on commercial vehicle operations especially in the nation's urban areas.

In light of these challenges, state transportation departments, metropolitan planning organizations and other involved in the planning process realize that they cannot build their way out of congestion. Many factors, such as construction costs, limited rights-of-way, and environmental and societal impacts make adding capacity through new general-purpose lanes unrealistic. These agencies are looking for solutions to improve the flow of traffic on existing facilities.

The evolution of geometric design criteria and emerging technologies has helped transportation agencies refine available strategies to meet growing freeway operations challenges. Transportation officials are now seeking to take advantage of opportunities to address mobility needs and provide travel options through a combination of limited capacity expansion coupled with flexible operating strategies that seek to manage travel demand and improve transit and other forms of ridesharing. The managed lanes concept is gaining interest around the country as an approach that combines these elements to make the most effective and efficient use of a freeway facility, address project and community objectives, and offer an alternative to congestion.

State of the Practice and State of the Art: A Look at Managed Lanes

The intent of this report is to review the state of the practice and state of the art in managed lanes in order to increase the understanding of (1) what managed lanes are, (2) how to plan for implementation, (3) what operational and design issues should be considered, and (4) how active management of the lanes over the life of the facility affect its implementation. This study describes operating managed lane projects through a case study approach, highlighting best practices and lessons learned. As a new concept in freeway management, managed lanes involve a number of design and operational issues that have yet to be addressed in practice. As such, emerging issues and knowledge gaps are also presented in this study.

For the purposes of this study, the "state of the practice" is defined as:

The proven practices in common use and the effective application of planning methodologies, financing approaches, public outreach strategies, highway geometric design techniques, and technologies commonly installed and operated in managed lanes within freeway facilities.

By comparison, the "state of the art" is defined as:

Innovative and effective practices in the application of leading edge methodologies, techniques, and technologies that are ready for deployment in managed lanes in terms of operating accurately and efficiently, but are not fully accepted and deployed by practitioners.

This study also addresses gaps in the knowledge, where emerging issues associated with methodologies, techniques, and technologies have not been fully implemented as the state-of-the-art and yet are critical elements of a fully flexible managed lane facility.

As an example, consider value-priced toll lanes as one form of managed lanes, and specifically the use of electronic toll collection on toll lanes:

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