Managed Lanes: The Future of Freeway Travel

Institute of Transportation Engineers. ITE Journal, Feb 2005 by Goodin, Ginger

TRANSPORTATION OFFICIALS ARE EXPLORING THE USE OF MANAGED LANES TO ADDRESS MOBILITY NEEDS IN FREEWAY CORRIDORS. THIS FEATURE PRESENTS EXAMPLES OF MANAGED LANES IN OPERATION AND ADDRESSES THEIR FUTURE, INCLUDING NEW PROJECTS ON THE HORIZON AND UNRESOLVED ISSUES ASSOCIATED WITH DESIGNING AND OPERATING A FULLY FLEXIBLE MANAGED LANE FACILITY.

INTRODUCTION

Transportation agencies are facing the growing challenges of traffic congestion and a limited ability to expand freeway capacity due to construction costs, right-of-way constraints and environmental and societal impacts. As a result, transportation officials are exploring the use of managed lanes to address mobility needs in freeway corridors, particularly where major expansion has limited feasibility.

Managed lanes provide travel options in a congested corridor through minimal capacity expansion and operational strategies that seek to manage travel demand and potentially improve transit and other forms of ridesharing (see Figure 1). The managed lanes approach is gaining interest around the United States as a strategy that combines these elements to make the most effective and efficient use of a freeway facility.

WHAT ARE MANAGED LANES?

The term "managed lanes" is increasingly recognized in the transportation profession. However, none of the managed lane facilities in operation today is communicated to the public using this term. As a project description, "managed lanes" could have a negative connotation to the general public, indicating that lanes are being managed or regulated or implying that the current freeway system is not effectively managed.

The term is gaining widespread use in the profession and will remain a useful professional term, but the managed lanes approach may be better communicated to the public at the project level using terms such as "express lanes," "toll express lanes," "value lanes," "fast lanes," or even "flex lanes."

Within the transportation profession, the term has different meanings depending upon the agency. In some agencies, managed lanes are commonly thought of as high-occupancy toll (hot) lanes-facilities that employ pricing and vehicle eligibility to maintain free-flow conditions and provide high-occupancy vehicle (HOV) preference.

In other agencies, a broader definition is customary, in which various management tools and techniques are combined 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, busonly, or truck-only lanes.

Figure 2 captures the potential lane management applications that fall into this broad definition of managed lanes. On the left of the diagram are applications of a single operational strategy-pricing, vehicle eligibility, or access control. On die right are more complicated managed lane facilities that blend more than one of these strategies. The multifaceted facilities on the far right of the diagram incorporate or blend multiple lane management strategies.

ACTIVE MANAGEMENT

The Federal Highway Administration (FHWA) views managed lanes in this broad sense, as highway facilities or sets of lanes where operational strategies are proactively implemented (in real time) and managed in response to changing conditions.1 Lane management strategies have been used by agencies for decades to improve flow on freeway facilities. The distinction between managed lanes and other traditional forms of freeway lane management is the operating philosophy of active management.

Under this philosophy, an operating agency proactively manages demand and available capacity on a facility by applying new strategies or modifying existing strategies. From the outset, the agency defines the operating objectives for the managed lanes and the kinds of actions that will be taken once predefined performance thresholds are met. The following examples show how demand on a managed lane facility can be reduced through a specific action:

* To maintain a speed of 60 miles per hour (mph), the operating agency raises the toll rate on a priced facility.

* To ensure that bus operating speeds of 50 mph can be maintained, the agency raises the occupancy requirement to use an HOV lane.

* To operate within a volume threshold of 1,500 vehicles per hour per lane, the agency closes an on-ramp to express lanes during peak periods.

The core of the active management philosophy is the development of clear performance objectives and operating threshold values that directly relate to the goals of the project. Additionally, a managed lane facility can be designed and operated to achieve different objectives during different days of the week or times of the day. For example, a facility could operate as HOV or hot lanes during peak periods, toll express lanes during off-peak periods and, potentially, a truck-only facility during certain times of the day.

RATIONALE FOR CONSIDERING MANAGED LANES

Transportation agencies may have a number of reasons for considering managed lanes in a freeway corridor. Among them are the following: