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13th International HOV/HOT Systems Conference: Partnerships for Innovation - Conference Proceedings
September 7-9, 2008
Minneapolis, MN

Scott Cooner, Texas Transportation Institute, Presiding

What’s Happening to the HOV Lanes: A National Examination of Changes in Operating Policies

Chuck Fuhs,
Parsons Brinckerhoff

Chuck Fuhs described changes in HOV policies and operating requirements over the past 35 years. He discussed current operating policies, possible future trends, and research needs. Chuck covered the following points in his presentation.

  • Many of the initial HOV lanes, including the Shirley Highway and the El Monte Busway, began as bus-only demonstration projects. Prior to 1987, the FHWA policy focused on a 3+ vehicle-occupancy level for HOV lanes. There were approximately 125 lane miles of HOV facilities in 1987. By 1995, a 2+ vehicle-occupancy requirement was used on most HOV projects, reflecting a change in FHWA policy. There were some 2,400 lane miles of HOV facilities in 1995.

  • Interest in expanding HOV lanes to include toll paying single-occupancy or lower-occupancy vehicles emerged during the late 1990s as one approach to maximize the use of facilities with available capacity. The managed lanes concept and the potential for generating revenue also influenced consideration of HOT projects. In some areas, HOT operations were considered as one approach to address HOV lanes that were over-utilized at the 2+ vehicle-occupancy levels, but would be under-utilized at the 3+ level.

  • HOV projects are currently located in metropolitan areas with high levels of traffic congestion in major travel corridors. Only six HOV projects have been terminated for various reasons since 1976. HOT projects are currently in operation in San Diego, Denver, Houston, Minneapolis, Salt Lake City, and Seattle. HOT projects in Miami, Los Angeles, and other areas are in various stages of planning and implementation. The I-95 HOT project in Miami, which is part of the UPA, will include increasing the vehicle-occupancy level from 2+ to 3+, and requiring carpools to register to use the lanes. Single-occupant vehicles and 2-person carpools will be required to pay a toll to use the HOT lanes.

  • Based on HOT projects in various stages of planning and implementation, it appears that operating HOT lane miles will double by 2012 and double again by 2015. Approximately half of these projects are expanding existing HOV lanes to include a HOT component, and half are new projects, which include a HOT element. It appears that most of these projects will continue to provide free travel for HOVs, and that increasing vehicle-occupancy levels when necessary to maintain desired travel speeds and travel-time savings will be considered on most projects. The exceptions to these trends are some new capacity projects, including those involving public/private partnerships, which may not provide free travel to HOVs.

  • There appears to be a shift in some areas from a focus on person movement to a focus on goals related to revenue generation or revenue augmentation, while also expanding investments in BRT and express bus services. Current trends indicate that HOV 2+ requirements may be increased to 3+ on both new and congested managed-lane projects, with a potential loss in person movement in those corridors. Obtaining public acceptance and support for major operational changes will continue to be important.

  • The operating strategies from 1969 to the present have focused primarily on vehicle eligibility, vehicle-occupancy levels, and access. Pricing and HOT operations emerged during in the late 1990s. Recently, emphasis is being placed on ATM in many areas. HOV and HOT lanes may become the logical facilities to test and implement the first automated highways in the future.

  • The experience with HOV and HOT projects continues to evolve. A better understanding of the impacts of pricing on different user groups and on operations is emerging. There continues to be a need to share information on the experiences with different HOV and HOT strategies and projects. There is also a need to document best practices, including the use of incremental steps to achieve agency and area goals and objectives.

  • The TRB HOV Systems Committee and other groups have identified research needs related to HOV and HOT facilities. One research need is identifying common HOV and HOT performance measures and performance data. Developing and conducting surveys of all user and non-user groups represents another ongoing research need. Developing techniques to estimate the possible impacts of different strategies on various segments of the population, evaluating mode shifts resulting from operational changes, and developing tools to support regional travel demand models and sketch planning techniques represent still other research needs.

Carpool Preferences in New Managed Lanes: Addressing the Question “HOT or Not?”

Ginger Goodin,
Texas Transportation Institute

Ginger Goodin discussed a recent study conducted by TTI for TxDOT examining carpool preferences with managed lanes. She described the research objectives, the study process, the preliminary findings, and the next steps. She recognized the assistance of Matthew MacGregor, TxDOT; Casey Dusza, TTI; and Mark Burris, TTI and Texas A&M University, with the study and presentation. Ginger covered the following points in her presentation.

  • The major research objective was to evaluate the tradeoffs associated with carpool preferences in managed lanes. This objective was accomplished by exploring the causal relationship between carpool pricing incentives and the propensity to carpool, documenting the state-of-the-practice in carpool preferences, and identifying the tradeoffs associated with preferential treatment.

  • The research process included a number of tasks. A state-of-the-practice review was conducted first. The results of this review were used to help design the survey instrument and to develop the impact analysis tool. The surveys were conducted and the results were used in the development of the impact analysis tool. Observational conclusions were also drawn from the survey results. The state-of-the-practice review, the impact analysis tool, and the observational conclusions from the survey were used in the development of the study implementation products, which included a decision framework, a webinar, a PowerPoint presentation, and a brochure.

  • The state-of-the-practice review identified a number of interesting points. First, the results revealed there is limited information about carpool incentives in priced managed lanes. Second, existing managed lanes or HOT lanes in Texas provide free access to HOV 3+. Projects in other parts of the country offer free access to HOV 2. Factors identified for consideration in setting managed lane carpool policy include enforcement of vehicle-occupancy requirements, maximizing vehicular throughput, and uniformity and equity considerations. The review also indicated a disconnect between regional carpool program objectives and managed lanes policies in many areas.

  • Surveys were conducted in Houston and Dallas in May through July 2006. Survey questions addressed personal travel patterns, opinions on managed lanes, stated preference on mode choice, and demographic information. The surveys were primarily Internet based, with responses collected on-line. The surveys were provided in both English and Spanish. The availability of the survey was widely advertised. Many organizations provided Internet links to the survey to help encourage participation. A total of 4,257 valid responses were recorded through the Internet survey. Minority and low-income respondents were not adequately represented, however.

  • To increase the number of responses from low-income and minority individuals, additional surveys were conducted at selected community centers and drivers license offices in Houston and Dallas. Individuals at these locations could complete the surveys in writing or using laptop computers. In addition to the 4,257 surveys completed through the Internet, 220 paper and 134 electronic surveys were completed at the sites.

  • Even with the additional surveys, minority and low-income travelers were under-represented in the final sample. At the same time, toll road users were over-represented in the sample. To address this issue, the results were weighed to better represent Houston and Dallas travelers. The weighing characteristics reflected four income groups, four ethnic groups, and toll versus non-toll road travelers.

  • The ability to access to HOV lanes was the highest rated reason for carpooling among respondents. Other reasons rated high included relaxation while traveling, enjoying travel with others, helping the environment and society, travel-time savings, and sharing vehicle expenses. The most frequently noted reasons for not carpooling include location/schedule limitations, lack of travel flexibility, the need for a vehicle during the day, and the need to make other stops during the commute trip.

  • Carpooling with an adult family member was the most frequently reported type of ridesharing arrangements. Approximately 44 percent of individuals in two-person carpools and 54 percent of individuals in three-person carpools reported traveling with an adult family member. Carpooling with co-workers or individuals in the same building or nearby building was the second more reported ridesharing arrangement, with approximately 25 to 28 percent. Other ridesharing arrangements reported included traveling with a child, casual carpooling, and commuting with a neighbor.

  • The managed lanes concept was explained prior to the questions on interest in using managed lanes. A cross-section diagram and a narrative description were provided to explain the design and operation of managed lanes.

  • The response to the question on interest in using managed lanes was examined by different user groups and socio-economic characteristics. Approximately 76 percent of toll road travelers reported interest in using managed lanes, compared to 69 percent of non-toll road travelers. Caucasians reported slightly more interest in using managed lanes than African-Americans and Hispanics. Individuals in higher income brackets reported higher interest in use than individuals with lower-income levels.

  • The reasons travelers gave for preferring or not preferring managed lanes were examined. The top ranked reasons given were traveling faster than in the general-purpose freeway lanes and travel-time reliability. Not wanting to pay a toll was the top ranked reason respondents identified why they would use the general-purpose freeway lanes over managed lanes. A dominate theme in many responses was that taxes already pay for the roads.

  • Stated preference questions provided respondents options between managed lanes and general-purpose freeway lanes based on different occupancy levels, different toll levels, and different travel times. The results from these questions were used in tradeoff analyses.

  • The impact analysis modeling was conducted to develop quantitative values for various measures of effectiveness. Researchers at the University of Texas, Arlington developed the modeling tool. The stated preference survey data was used to develop the model for predicting mode choice in priced lanes. The I-30 corridor in Dallas was used in the analysis, which focused on the peak hour.

  • Different carpool policy scenarios were examined. Examples of these carpool policies included requiring all HOVs to pay a toll, allowing all HOVs to travel for free, and different combinations of varying the toll by vehicle-occupancy levels. A total of six different carpool scenarios were examined. The four toll levels for single-occupant vehicles were $0.10 a mile, 0.25 a mile, $0.50 a mile, and $0.37 to $0.45 a mile to optimize for 60 mph in the managed lanes.

  • The average speeds in the managed lanes and the general-purpose freeway lanes were analyzed at the different pricing levels for the six carpool policy scenarios. Speeds in the managed lanes were higher with higher toll levels and with some or all HOVs paying the full toll or a partial toll. Speeds in the general-purpose freeway lanes were lower under these conditions, as fewer travelers would be willing to change to the managed lanes due to the higher tolls.

  • The revenue impacts of the different toll levels on the six scenarios were also examined using the model. Revenue as a percentage of the base case, which tolled all vehicles using the managed lanes, was examined. Only three carpool policy scenarios at the $0.50 per mile rate were above the base case. These carpool policy scenarios were HOV 3+ paying a 50 percent toll and HOV 2 paying full toll, all HOVs paying a 50 percent toll, and HOV 3+ traveling for free and HOV 2 paying a 50 percent toll.

  • The percent increase in person throughput from the base case was examined using the model. The carpool policy scenarios of all HOVs traveling for free and the $0.50 toll rate resulted in the highest throughput due to the higher number of vehicles in the managed lane.

  • The carpool policy scenarios were analyzed by six managed lanes performance objectives. The objectives were person throughput, revenue generation, emissions reduction, operational performance, enforcement and operational simplicity, and public perception and support. The relative success of each scenario in achieving the performance objective was rated as high, medium/neutral, or low.

  • A number of findings emerged from the study. First, HOV preferences in managed lanes can influence carpooling behavior. Second, family member carpools make up the majority of carpools in Texas, and HOV access rates high in the responses from these carpools. Support for managed lanes is high in Dallas and Houston. Faster travel and travel-time reliability were the most important reasons for support among respondents. Carpool preferences can offer advantages in increasing person-moving capacity in congested travel corridors. Policies that emphasize peak periods may be more effective in targeting commuter/ acquaintance carpools. The determination of the appropriate carpool policy in managed lanes depends upon individual project objectives.

HOT and HOTTER Lanes

Don Samdahl,
Fehr & Peers/Mirai

Don Samdahl discussed the consideration of HOT lanes and pricing strategies in the Puget Sound Region. He summarized the results of the Urban Areas Congestion Relief Analysis study conducted for WSDOT. He highlighted factors influencing the consideration of HOT lanes and pricing in the region, the HOT and pricing scenarios examined in the study, and some of the study results. Don covered the following points in his presentation.

  • A number of factors are influencing consideration of HOT lanes and pricing in the Puget Sound Region. These factors include increasing traffic congestion and growth pressures, limited funding for new capacity and operations, and concerns about climate change. There are specific needs associated with funding key transportation infrastructure elements in the region, including the SR 520 floating bridge across Lake Washington.

  • Population, employment, and person trips per day are all projected to increase in the region. The existing vehicle hours-of-delay is 285,500 per day. The vehicles hours-of-delay projected for 2025 is 1.1 million a day. From 1994 to 2005, HOV volumes grew faster than general-purpose freeway lane volumes on I-5. As a result, the HOV lanes on I-5 and HOV lanes on other freeways in the area are experiencing congestion.

  • One option to address this concern is to raise the vehicle-occupancy requirement from 2+ to 3+. While this change might increase the speeds on the HOV lanes, modeling results indicate that HOV demand would decline. HOT lanes represent another option for addressing congestion in the HOV lanes.

  • Three scenarios were examined in the study. The HOT 1 scenario included converting the existing HOV lanes to HOT lanes. The HOT 2 scenario included converting the existing HOV lanes to HOT lanes and adding 366 lane miles of HOT lanes in heavily congested freeway segments. The hybrid HOT lane scenario included two HOT lanes in the peak direction of travel and one reversible lane in the peak direction. It also included fully-managed freeway corridors through Seattle and crossing Lake Washington. Further, direct HOT access at key interchange locations would be provided. The hybrid scenario was developed to address the imbalanced directional flows that occur in the peak-periods.

  • A number of challenges were encountered in conducting the study. These challenges included determining the value of time and the toll rates to be used. Other challenges focused on time-of-day travel, mode splits, and trip rates.

  • Four evaluation matrices were used in the study. These matrices were total delay and delay per trip, travel time along frequent commutes, potential throughput gain, and potential cost.

  • The analysis indicated that the HOT lanes should improve person throughput. Person throughput increases by allowing HOT users to fill the remaining capacity of an existing HOV lane using a 3+ vehicle-occupancy requirement. Congestion is reduced in the general-purpose freeway lanes resulting in more efficient use of general-purpose freeway lanes.

  • The capital costs associated with the different scenarios were developed. The capital cost of the HOT 1 scenario was estimated at $320 to $430 million, assuming a two-foot inside shoulder and a two-foot striped buffer. The capital cost of HOT 2 scenario was in the $15 to $22 billion range, assuming 10-foot inside shoulder and a four-foot buffer. The capital cost of the hybrid scenario was in the $10 billion range, assuming a 2 to 10 foot inside shoulder and two-to-four foot buffer.

  • The influence of region-wide pricing was also examined in the study. Two general pricing scenarios were tested. The first scenario used fixed tolls, with a constant price throughout the day. The toll rates examined were $0.10, $0.20, and $0.30 per mile. The second scenario used variable tolls. The two options were varying the price based on congestion levels on each roadway segment and varying the price by time period. The toll rates examined in the variable pricing options ranged from $0.05 to $0.20 per mile.

  • The analysis results indicated that conversion of the HOV lanes to HOT lanes improves travel-time reliability, but the total reduction in delay is small. The two-lane HOT lane network offers more benefits but the cost is very high. Region-wide congestion pricing is most effective in reducing congestion, but there are policy and public acceptance implications with this option.

  • A number of other studies and projects in the area will contribute to the discussion underway concerning HOT lanes and pricing, including the SR 167 HOT lane pilot study and the Transportation 2040 Plan. Further, a decision on SR 520 may be made soon. The Transportation 2040 Plan includes five tolling scenarios as part of each regional alternative. The scenarios were a one-lane HOT facility with a 3+ vehicle-occupancy requirement or a two-lane HOT facility with a 2+ vehicle-occupancy requirement, selected facility tolling, area pricing and parking, freeway system tolling, and full system tolling. A number of factors are being considered with the need for tolls to fund the SR 520 Bridge. These considerations include beginning tolling in 2010 or in 2016, tolling just SR 520 or tolling both SR 520 and I-90, and the tolling rate to use. Tolls of up to $4.00 in each direction of travel were tested.

The Life Cycle of Managed Lanes: Impacts of Multiple User Groups

Myron Swisher,

Myron Swisher discussed the life cycles of HOV lanes and HOT lanes. He described possible variations in the life cycle based on flat HOV growth, revenue generation as a priority, and hybrid vehicle access. He recognized the assistance of David Ungemah, Ginger Goodin, and Bill Eisele from TTI with the preparation of the presentation. Myron covered the following points in his presentation.

  • User groups of traditional HOV lanes typically include transit riders, carpools, and vanpools. In most cases, 2+ carpools represent the majority of vehicles using an HOV lane, which would be underutilized with only buses and 3+ carpools. With significant growth in 2+ carpools over time, however, demand will at some point exceed capacity. One option to address this problem and to maintain freeflow conditions in the HOV lane is to raise the vehicle-occupancy level to 3+ and restrict use by two-person carpools.

  • In the traditional HOT lane application, single-occupant vehicles are allowed to use an HOV lane for a fee while buses and 2+ carpools travel for free. HOT lanes may experience the same growth in 2+ carpools as HOV lanes, with demand exceeding capacity in the lane. One approach to address this problem and to maintain freeflow conditions in the HOT lanes is to toll two-person carpools, as well as single-occupant vehicles, while allowing 3+ carpools and buses to travel for free.

  • HOV lanes may also be expanded to HOT lanes to address a scenario of flat HOV growth. In this scenario, HOV 2+ demand never reaches capacity. Tolled single-occupant vehicles are allowed to use the available capacity created by this situation. In this scenario, the growth in tolled vehicles may also be flat, allowing tolled vehicles and 2+ HOVs to use the lane into perpetuity.

  • Another possible scenario focuses on revenue generation as a priority. In this scenario, providing access to toll-paying vehicles is a higher priority than providing access to HOVs. As the HOT lane reaches capacity, two-person HOVs are required to pay the toll similar to single-occupant vehicles. If the facility reaches capacity under this operation, 3+ carpools would also be required to pay a toll.

  • A final scenario allows low emission and energy-efficient vehicles, including qualifying hybrid vehicles, to use the HOT lanes without paying a toll. Currently, the growth rate for hybrid vehicles is not well understood. A number of options might be considered as HOT lanes allowing hybrid vehicles reach capacity. These options include terminating hybrid vehicle use, tolling hybrid vehicles, and tolling two-person HOVs. This scenario has more user groups than other scenarios. The HOV lane on I-95 in northern Virginia provides one example of hybrid vehicle use of an HOV lane. In 2005, approximately 1,760 3+ HOVs and 300 hybrid vehicles were using the lane in the peak hour. A significant growth in hybrid vehicle use would degrade the level-of-service in the HOV lane.

November 2009
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