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|Federal Highway Administration > Publications > Public Roads > Vol. 68 · No. 3 > Managed Lanes|
Publication Number: FHWA-HRT-05-002
by Jon Obenberger
Combining access control, vehicle eligibility, and pricing strategies can help mitigate congestion and improve mobility on the Nation's busiest roadways.
As the public's desire to travel on highway facilities continues to grow, so will the levels of congestion. In fact, traffic congestion has expanded beyond traditional peak travel periods into a problem that has the potential to disrupt travel and commerce drastically at any time throughout the day.
The continued growth in travel demand exceeds agencies' abilities to provide sufficient roadway capacity based on limited public funding for roadway expansion projects. High construction costs, constrained rights-of-way, and environmental factors are pushing agencies to explore other alternatives, including managed lanes, to mitigate the detrimental effects of congestion while optimizing the use of limited public funding. The consideration and use of managed lanes is growing rapidly in major metropolitan areas as an innovative and cost-effective approach to address congestion within urban freeway corridors.
"Managed lane strategies can maximize existing capacity, manage demand, offer choices, improve safety, and generate revenue," says State Traffic Engineer Carlos Lopez from the Texas Department of Transportation (DOT). "The Texas DOT believes that managed lanes leverage existing capacity and move both people and goods in the most efficient manner possible."
The concept of managed lanes involves proactively applying proven operational strategies in response to changing traffic and roadway conditions. By actively managing and controlling traffic though a combination of access control, vehicle eligibility, and pricing strategies, agencies can keep vehicular demand and roadway capacity in balance by taking the appropriate actions before congestion forms.
Defining Managed Lanes
Currently the concept or definition of "managed lanes" varies from agency to agency. To some, the phrase refers only to high-occupancy toll (HOT) lanes, which are facilities that combine pricing and vehicle eligibility to maintain free-flow conditions while still providing a travel time-savings incentive for high-occupant vehicles. Other agencies use a broader definition that may include high-occupancy vehicle (HOV) lanes, priced lanes, HOT lanes, and special use lanes (such as express, bus-only, or truck-only lanes).
The Federal Highway Administration (FHWA) defines managed lanes as highway facilities or a set of lanes in which operational strategies are implemented and managed (in real time) in response to changing conditions. Managed lanes are distinguished from other traditional forms of lane management strategies in that they are proactively implemented, managed, and may involve using more than one operational strategy.
Traditionally, agencies have used various lane management strategies on freeway facilities—including reversible flow lanes, express lanes, HOV lanes, truck lanes, and toll facilities—in a manner that typically does not involve any active management or variation in how traffic is controlled in response to changing conditions. By comparison, possible examples of managed lanes may include the following: HOT lanes with tolls that vary based on demand; exclusive bus- and truck-only lanes; HOV and clean air and/or energy-efficient vehicle lanes; and HOV lanes that could be changed into HOT lanes in response to changing levels of traffic and roadway conditions.
Assessing the Benefits
According to Ginger Goodin, with the Texas Transportation Institute and chair of the Transportation Research Board's (TRB) Joint Subcommittee on Managed Lanes, "If you subscribe to the notion that you cannot build your way out of congestion in developed urban freeway corridors, then managed lanes offer an opportunity to preserve a portion of the freeway capacity for a higher level of service. That capacity does not necessarily have to be used exclusively for personal automobile mobility but can be operated flexibly to incorporate transit and ridesharing options according to the needs and goals of the community."
Transportation agency experience is beginning to show that managed lanes help control demand; improve the safety, mobility, and performance of freeways and transit systems; and offer travel options that save time and enhance the reliability of travel times. Revenue also may be generated when one of the operational strategies involves pricing, where a toll is charged to a specific group of vehicles that would not otherwise have been eligible to use a managed lane if it was being operated as only an HOV lane.
Managed lanes offer the potential to improve the range of benefits that agencies typically realize from traditional freeway management strategies. According to FHWA's Freeway Management and Operations Handbook (FHWA-OP-04-003), traditional freeway management strategies have the potential to reduce travel times up to 48 percent, increase travel speeds up to 62 percent, increase vehicle throughput on roadways up to 25 percent, decrease crashes by up to 50 percent, and reduce delay caused by crashes that block traffic by up to 50 percent. Managed lanes also might improve the public perception of how agencies manage the operation of freeway facilities and attempt to mitigate the impacts of congestion. A 2001 survey of I-15 users in San Diego showed that 92 percent of respondents agreed that managed lanes on I-15 are an effective time-saving option.
Improving the Operation Of Freeway Facilities
FHWA recommends implementing the appropriate operational strategies, control plans, and actions before the flow of traffic breaks down. The use of HOV lanes is one of the proven and effective operational strategies that agencies have implemented to improve the performance of freeway facilities.
Because HOV lanes carry vehicles with a higher number of occupants, they have the potential to move more people in a smaller number of vehicles, in comparison to the adjoining general purpose travel lanes, during congested travel periods. The reversible-flow HOV lanes on I-95 in northern Virginia, for example, demonstrate the potential to carry a significantly larger number of people in a smaller number of vehicles. In the fall of 2003, the Virginia DOT reported that during the morning peak travel period (6:00 to 9:00 a.m.), the HOV lanes carry 54 percent of the total number of people in 27 percent of the total vehicles on only 40 percent of the freeway lanes capacity (two HOV lanes in comparison to three general purpose lanes).
Similarly, commuters using HOV lanes in Texas save an average of 2 to 18 minutes during the peak hour, according to the Texas Transportation Institute's ABCs of HOV: The Texas Experience, Report 1353-I. Benefit-cost ratios for HOV lanes in Texas have been estimated to range from 6:1 to 48:1, in comparison with a base case involving the addition of the same number of general purpose lanes.
HOV lanes may be warranted outside the traditional peak commuting periods to deliver travel-time incentives to vehicles with more than two occupants, whenever congestion may occur along urban freeway corridors. During offpeak travel periods, the Washington State DOT has found HOV lanes to be a viable operational strategy. A study performed in the Seattle area on weekend use of HOV lanes showed that the average number of people in each car was higher than expected, as 30 to 60 percent of the traffic was eligible to use HOV lanes. The DOT reported that when congestion occurred during the weekends, more vehicles used the HOV lanes.
The use of HOV lanes or occupancy as the only operational strategy may not be appropriate in every location or for all time periods during the day. Even after HOV lanes are installed, changes may occur in land use, the kinds of trips people take, the times people travel, and the levels of traffic congestion that may exist along a freeway corridor. These are changes that may warrant adjustments in how an HOV lane may be operated.
During peak travel periods in many metropolitan areas, the HOV lanes are already operating at or very close to their maximum vehicle carrying capacity. However, during other times of the day, the opportunity may exist for other types of vehicles to use these lanes, based on the available roadway capacity. The National Research Council's HOV Systems Manual (NCHRP Report 414) states that HOV lanes are viable when the HOV-eligible traffic ranges from 400 to 600 vehicles per hour. This is in comparison to the maximum vehicle carrying capacity of an HOV lane, which may vary from 1,200 to 1,800 vehicles per hour per lane.
Historically agencies have had limited options available to improve the performance of HOV lanes. When the demand to use HOV lanes exceeded capacity, agencies traditionally either expanded the number of lanes or increased the occupancy level required for vehicles to use the lanes to maintain free flowing traffic conditions. Raising the occupancy level typically results in a significantly lower number of vehicles eligible to use the HOV lane, often resulting in a situation where the public may view the facility as underutilized. Agencies also have had limited options when the demand to use an HOV lane may be low. Managed lanes, however, offer traffic managers an opportunity to improve the operational performance of HOV lanes and proactively respond when they are faced with similar situations.
Implementing Managed Lanes
One managed lane technique that agencies have implemented successfully to improve the performance of freeway facilities involves combining the use of tolls with vehicle occupancy requirements, in the form of a high-occupancy toll (HOT) lane. HOV lanes alone do not qualify as managed lanes, but when coupled with another operational strategy (such as pricing), or if real-time changes are made in their operation in response to changing conditions, then they would be considered a managed lane. As traffic and roadway conditions change throughout the day, agencies can modify the occupancy level established for vehicles to use a managed lane for free along with the fee that is charged to vehicles that would not otherwise be able to use the HOT lane. These decisions and operational changes will directly influence travel demand and performance on both the managed lane and the adjoining general purpose travel lanes.
The U.S. Department of Transportation's Value Pricing Pilot Program encourages the use of value pricing in the form of new tolls on existing toll-free facilities (such as HOT lanes), variable tolls on new lanes, variable tolls on toll facilities, and usage-based vehicle charges. "Value pricing is a way of harnessing the power of the market to reduce traffic congestion, improve the environment, and contribute toward the financing of transportation options," says Patrick DeCorla-Souza, team leader for the Highway Pricing and System Analysis Team with the FHWA Office of Transportation Policy Studies.
"The key to operating managed lanes successfully is the ability to alter the operation of the lanes in ways that keep traffic flowing," adds Lopez from the Texas DOT. "This strategy provides flexibility, not only in the day-to-day operation of the lanes, but also in situations where isolated incidents, such as major crashes, call for the lanes to be open to more or different user groups."
Examples of operational changes agencies have made to maintain freeflow travel conditions on managed lanes while improving the overall performance of the freeway facility include the following:
Another concept gaining interest is the use of truck-only toll (TOT) lanes, where tolls would be charged to trucks choosing to use a lane or facility that would be restricted to other vehicles. These lanes would enable shippers to stay on schedule, reduce operating costs, bypass local traffic, and meet freight deadlines. The gains for the public might include improved safety, ontime deliveries, and less congestion.
In a recent article, USA Today's Debbie Howlett noted that "Texas, Virginia, and California officials . . . are looking at building TOT lanes on major truck corridors in their States." In addition, in the Atlanta Business Chronicle's article, "Truck, 'HOT' lanes might cool off traffic," Sarah Rubenstein discusses Georgia's plan to study the concept. "Not only is the State Road and Tollway Authority [Atlanta, GA] planning a study of potential spots for HOT lanes, which allow individual drivers to escape congestion by paying tolls to use highoccupancy vehicle (HOV) lanes, but it's also considering a similar idea that would specifically cater to trucks."
Experiences and Lessons Learned
The experiences and lessons learned from the limited number of managed lanes that have been implemented represent a valuable source of information, especially because many of these concepts are new in transportation applications. The studies on these facilities, the experiences that will be documented by the FHWA Value Pricing Pilot Program's upcoming report to Congress (Report on the Value Pricing Pilot Program, due spring 2005), and the results compiled from a Managed and Priced Lanes Workshop (FHWA and TRB, November 2003) provide answers and perspectives where technical guidance does not currently exist.
On State Route (SR) 91 in Orange County, CA, four express lanes (HOT) in the median of the 12-lane freeway make use of occupancy and variable pricing to ensure efficient flow of traffic and to maximize vehicle throughput and travel speeds. In 2004, speeds on the SR-91 express lanes traveled at 96 to 104 kilometers per hour, km/h (60 to 65 miles per hour, mi/h), while congestion on the free lanes reduced average speeds during peak hours to no more than 24 to 32 km/h (15 to 20 mi/h). As a testimony to the success of this strategy, the share of vehicles carried in the peak direction in the peak hour of an average week on the express lanes has increased to 49 percent. The two express lanes each carry almost twice as many vehicles per lane as the four adjoining free lanes, and they do so at three-to-four times the speed on the unpriced lanes.
San Diego, CA, also is using HOT lanes. The FHWA/TRB Managed and Priced Lanes Workshop summary publication states, "In San Diego, on the I-15 HOT lane facility prices can change as often as every 6 minutes, by as much as 25 (or 50) cents." According to Ray Traynor, senior project manager for the San Diego Association of Governments (SANDAG), 75 percent of the vehicles traveling in the I-15 HOT lanes (known locally as FasTrak lanes) still ride for free as HOVs, while 25 percent pay a toll. "The FasTrak lanes now yield about $2.2 million in annual collections revenue—enough to run the program and pay for two Rapid Transit buses for the I-15 route, but not enough to float bonds to build new lanes," says Traynor.
Agencies should be aware of, consider, and prepare for the following key institutional, organizational, and technical issues that they may encounter throughout the key phases in the life cycle of a managed lane facility.
Institutional issues include the following:
Organizational issues include the following:
Technical issues include the following:
Keys to Success
FHWA expects that the number of managed lane facilities in operation will increase significantly in the coming years, as agencies begin implementing new projects based on commitments associated with feasibility studies already completed. These new managed lanes will represent a combination of new or reconstructed facilities as well as changes in the ways roadway owners manage the operation of existing facilities (such as converting HOV lanes to HOT lanes). Agencies have identified the following as key factors that have contributed to the success of the managed lane facilities that they have planned, designed, or are currently operating:
Managing and controlling traffic on dual or separate roadways that are interconnected on the same freeway facility presents new challenges for agencies to address and overcome in the planning, design, implementation, enforcement, and evaluation of managed lane facilities and the strategies used to operate them. Although many of these challenges appear to be similar to what agencies may have encountered previously with HOV lanes, managed lanes present many new and complex issues that will require information and answers.
"The Texas DOT embraced the idea of managed lanes in its congested urban freeway corridors but also recognizes that the idea is more than a concept," says Goodin from the Texas Transportation Institute. "There are practical implementation issues that need to be addressed. Although frequently cited examples of managed lanes, such as California's I-15 and State Route 91, are models of successful projects, they are somewhat simplistic in their operating approach. The next generation of projects under development in Texas and elsewhere are more complex in terms of ingress/ egress locations, access treatment, enforcement, and transit integration."
Currently underway, the following key activities are beginning to identify and deliver the research results and technology transfer products that practitioners will need to consider, implement, and utilize managed lanes successfully:
"Managed lanes will play an increasingly important role in congested corridors. Encouraging and supporting the successful planning, implementation, and operation of managed lanes will require the collective support of professional organizations, in addition to FHWA," says Associate Administrator of Operations Jeff Paniati at FHWA. "A new focus on research, technical guidance, training, technology transfer, and outreach is needed to increase awareness of the potential benefits that managed lanes have to offer and to advance their use."
Managed lanes provide the opportunity to manage and control traffic proactively, in response to changing traffic and roadway conditions on freeway facilities. For that reason, they are a key strategy that agencies and highway officials can use to improve safety and mitigate the impacts of congestion efficiently and effectively. Although some applications of managed lanes are more developed than others, as the transportation community finds new ways to combine various lane strategies, more innovations are likely to surface in the future.
Jon T. Obenberger, P.E. is the team leader for the Preconstruction Group within the FHWA Office of Infrastructure. Prior to this appointment, he served as manager of the freeway management program located in the Office of Transportation Management within the FHWA Office of Operations. In that capacity, he focused on freeway management systems, traffic management systems, and high-occupancy vehicle and managed lane systems.
The author would like to express his appreciation to the following individuals who provided insight, guidance, and valuable perspectives on the issues and topics in this article: Patrick DeCorla-Souza, leader of the Highway Pricing and System Analysis Team, FHWA Office of Transportation Policy Studies; and Jeffrey A. Lindley, Director of the Office of Transportation Management, FHWA Office of Operations.
For more information on managed lanes, contact Jon T. Obenberger at 202-366-2221 or email@example.com.
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