David H Ungemah

Investigating the Impact of Tolls on High-Occupancy-Vehicle Lanes Using Managed Lanes

For nearly 40 years, high-occupancy-vehicle (HOV) lanes have been used to combat congestion. These lanes allow only vehicles with multiple occupants and generally offer a free-flow trip, unlike adjacent general purpose lanes. In theory, this encourages additional carpooling, reduces overall vehicle miles of travel, and improves the commute trip. However, as a result of the underutilization of some of these lanes, some HOV lanes are migrating to high-occupancy-toll (HOT) lanes, where HOVs may travel free of charge but lower-occupancy vehicles can pay a toll to use the lane. This research investigated the impacts of offering preferential treatment for HOVs on these lanes. To determine the impact of different HOT lane operating strategies on their travel behavior, freeway travelers in the Houston and Dallas metropolitan areas of Texas were surveyed. A nested logit model was developed to estimate the mode choice for travelers. This model was used to predict the impact of converting an HOV lane to a HOT lane on which all travelers pay a toll. It was found that the overall percentage of HOV2 and HOV3+ vehicles in the traffic stream decreased by only a small amount when a toll was required for them to use the HOV lane. However, that decrease did represent a significant portion of those modes (more than 9%) and resulted in more than a 10% increase in HOT lane revenue. Therefore, elimination of preferential treatment for these vehicle types has significant implications and becomes a difficult policy decision—not just a straightforward choice.

Examining Incentives and Preferential Treatment of Carpools on Managed Lane Facilities

As managed lanes (MLs) are considered throughout more than 25 North American cities, there is a need for guidance in defining the role of carpools in tolled MLs and the trade-offs between carpool exemptions and other project objectives. Increasingly, project objectives are reflecting not only mobility concerns but the need to generate revenue as well. As a result, allowing exempt or discounted users, such as carpools on priced-MLs, requires an evaluation of revenue impacts as well as mobility interests such as person movements, operations, and emissions. This paper highlights the existing body of knowledge regarding carpooling, facilities, and incentives designed to encourage carpooling and related contributions to society. Following a review of literature, state and regional entities involved in either operating existing ML facilities or planning for new facilities were interviewed to determine the rationale for setting their carpool policies.

Discussing High-Occupancy Toll Lanes with the Denver, Colorado, Public

As managed lanes and high-occupancy toll (HOT) lanes gain popularity as a potential mobility measure, the question of how the public views these relatively new concepts is of vital importance. Concerned that a potential conversion of the North I-25 high-occupancy vehicle (HOV) facility in Denver, Colorado, to HOT lanes could be perceived as too controversial, the Colorado Department of Transportation (CDOT) sponsored market research and public outreach and assessment for evaluating the level of controversy. The messaging, methodology, activities, and findings from this effort may provide valuable information for communities that are considering HOT lanes as a component to their mobility challenges. This paper outlines the efforts conducted by CDOTs project team, including focus groups with commuters and business owners, stakeholder outreach to vested public officials and interest groups, conversations with the public in varying open houses, and a stated preference telephone survey. The conclusions from t...

LIFE-CYCLE GRAPHICAL REPRESENTATION OF MANAGED HIGH-OCCUPANCY VEHICLE LANE EVOLUTION

High-occupancy vehicle (HOV) lanes usually go through an evolution of stages in their life cycle. The typical evolution includes changes in demand levels from several modes including 2+ or 3+ carpools and vanpools, transit, and general-purpose vehicles. To ensure adequate usage, most facilities have started out with a designation of HOV2+. In some cases, over time, HOV2 volumes have exceeded the capacity of the facility, which has caused delays for transit vehicles. Therefore, there is an inevitable need for managing the hierarchy of facility users over time. A graphical tool is presented that indicates the life span of a managed HOV lane, and it can be applied to a variety of existing and planned managed HOV lane projects. The graphic was used in Colorado, Florida, and Texas in communicating the managed lane concept to transportation professionals. Further, the graphic was used to explain the historical operation of a managed HOV lane facility and the likely progression if current management policies remain in effect, based on experiences in similar facilities. Alternative management strategies can also be evaluated and compared with the graphical tool. The graphical representation of this managed HOV lane concept is anticipated to be valuable for transportation professionals in many areas (e.g., highway, tolling, and transit) in presenting and understanding operating scenarios for managed lanes over time and how they meet the goals of the facility. Applications of the life-cycle graphic to various facilities in the United States are also presented.

Automated Vehicle Occupancy Verification Systems: Policy and Legal Implications

Managed lanes require effective vehicle occupancy enforcement policies and programs to operate successfully. Several semi- and fully automated techniques for determining the number of persons in a moving vehicle, including operator-monitored video cameras and infrared composite imaging, have undergone limited field testing. The technical merits of invehicle and roadside systems for automated vehicle occupancy verification systems have been examined extensively. This paper complements those efforts by providing the policy and legal implications of automated systems for occupancy enforcement. The primary form of automated enforcement technology currently used in the United States is photographic imagery recorded by automated violation detection systems. For moving violations, these systems almost exclusively take the form of red light and speed enforcement, unlike toll evasion, which is typically punishable as an infraction. Principal objections to automated enforcement for occupancy purposes have involved privacy and due process concerns. Under an automated occupancy enforcement tool, the occupancy enforcement regime would likely face the same legal and privacy challenges as automated enforcement cameras and similar devices. This paper examines the current legislation related to automated enforcement practices, as well as an illustration of the arguments against their use. These arguments raise questions about the legality of automated enforcement systems and the perceived invasion of privacy some drivers may associate with such systems. The three primary privacy issues associated with an automated system for occupancy enforcement concern the photographic record of occupants, vehicle infrastructure integration barriers, and the legal definition of a high-occupancy vehicle infraction.