Increasing traffic congestion in major metropolitan areas is costing billions of dollars each year in lost productivity, wasted fuel, increasing air pollution and hours of delay. Adding new general purpose lanes is increasingly difficult because of factors such as construction costs, limited right-of-way, and environmental and societal concerns, so agencies are looking for solutions to improve the flow of traffic on existing facilities. One such solution is the concept of “managed lanes.” Through managed lanes, a variety of management tools and techniques (including include pricing, vehicle eligibility, and access control) are employed to improve freeway efficiency and to achieve optimal travel conditions. Examples of managed lanes include High-Occupancy Vehicle (HOV) lanes, value-priced lanes (such as High-Occupancy Toll, or HOT lanes), and exclusive or special use lanes (such as express, bus-only, or truck-only lanes).
This study reviews the state of the practice and the state of the art in managed lanes in order to increase 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 uses a case study approach, highlighting best practices and lessons learned from four managed lanes projects, including:
- State Route 91, California
- Interstate 15, San Diego
- I-10 and US 290, Houston (also known as the QuickRide program)
- New Jersey Turnpike
For the purposes of this study, the research team focused on state of the art facilities that utilize pricing, but also employ a combination of other basic managed lane operational strategies (i.e. vehicle eligibility and access control).
Successful managed lanes projects require active management and a consideration of the life-cycle characteristics of the facility. As conditions in a corridor change or the objectives of the community change, the operational strategy of a facility may also have to change. As a project develops, it is important to recognize and communicate to the public and to policy makers the possibility of change. ITS technologies enable active monitoring of managed lanes, providing information that can be used to develop or refine operational strategies as needed. An active management premise includes the following key elements, presented as a set of lessons learned:
- Allow for flexibility. Successful projects must have the flexibility to alter operations. By including flexibility as a design element, the facility’s life may be extended because operations on the facility can be changed as traffic conditions in the corridor change or as community objectives for the project change.
- The two managed lane facilities in California, for example, offer the flexibility of variable and/or dynamic tolling.
- Establish threshold values. Threshold values should be established for maintaining a prescribed level of operating service.
- At its inception, SR91 used traffic and revenue studies to determine traffic volume threshold values that would allow conditions to remain free-flow at 50mph and that would generate enough revenue to provide a return on investment to the private company that financed, built and operated the facility. Ownership of the facility has reverted back to a public agency, and Orange County Transportation Authority has established a new toll policy that clearly defines the triggers of toll increases and decreases for the peak hours based on traffic volumes for the corridor.
- The San Diego Association of Governments (SANDAG) also has set critical operating thresholds for the I-15 Express Lanes by establishing parameters for operations that included specific level of service requirements so as not to adversely affect the HOVs on the facility.
- Establish a hierarchy of users. Determining a hierarchy of users may be an important goal for a managed lanes project. Depending on the objectives of the project, operators will need to establish a hierarchy of users and design and manage the facility to maximize the convenience offered to these users.
- On the I-15 Express lanes and on the QuickRide project, preferential treatment has been given to HOVs, and specific parameters have been set so as not to adversely impact the HOVs traveling on those facilities.
- SANDAG has given priority to transit users, using revenues collected from the I-15 managed lanes project to fund transit service in the corridor.
- Monitor and evaluate the project. Under active management, there is a need for the continual monitoring and evaluation of managed lanes. Specific performance measures are defined at the outset, and then the project is monitored to ensure that those performance targets are being met. Monitoring technology, such as vehicle sensors, automatic vehicle identification, license plate recognition and user information systems can be used to assist in the monitoring of the facility. In addition, more comprehensive historical data and contextual data (i.e. population, employment, land use) must be collected and analyzed to determine if adjustments to operations are necessary.
- On the SR 91 Express lanes, for example, operators have raised tolls several times as a result of increased congestion on the facility.
Through active management of managed lanes projects, performance measures and operating thresholds are established at the outset and then the facility is monitored accordingly. Adjustments to operations are made as necessary, to insure that capacity is being effectively utilized and that the facility is operating as efficiently as possible, thus maximizing mobility benefits to the corridor.
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