Houston Managed Lanes Case Study: The Evolution of the Houston HOV System
Traffic congestion continues to be a major issue in metropolitan areas throughout the country. The agencies responsible for the surface transportation system in these regions are using a variety of approaches and techniques to address concerns relating to traffic congestion, mobility, and air quality. The use of high-occupancy vehicle (HOV) facilities and managed lanes represent two related approaches in use or being considered in many urban areas.
HOV facilities are an important element of the transportation system in Houston. HOV lanes and supporting facilities are in operation in six freeway corridors. Building on the success of the HOV facilities, managed lanes are being developed in one freeway corridor and are under consideration in a second corridor.
The Federal Highway Administration (FHWA) sponsored this study examining the development and operation of the HOV system in Houston and the evolution toward managed lanes. This report summarizes the background and the current status of the Houston HOV system and the development of the first managed lanes project. It also highlights some of the issues that may need to be addressed in considering managed lanes. This report is intended for agency staff, consultants, and policymakers interested in pursuing new or enhancing existing HOV facilities and managed lanes.
This study accomplishes a number of objectives. The first objective of the study is to describe the development, operation, and use of the HOV system in the Houston area and the evolution toward managed lanes. The institutional arrangements and the factors influencing the development of the system are also summarized. A good deal of information is available in other documents on the use of the Houston HOV lanes. This report provides an overview of the development and use of the HOV system and the institutional arrangements that have helped foster the evolution of the system. A final study objective is to describe some of the issues typically associated with HOV facilities and managed lanes to assist transportation professionals interested in considering HOV and managed lanes.
HOV facilities represent one approach used in metropolitan areas throughout the country to help improve the people-moving capacity rather than vehicle-moving capacity of congested freeway corridors. The travel time savings and improved trip time reliability offered by HOV facilities provide incentives for individuals to change from driving alone to carpooling, vanpooling, or riding the bus.
The development and operation of HOV facilities have evolved over the past 30 years. The opening of the bus-only lane on the Shirley Highway (I-395) in Northern Virginia/Washington, D.C. in 1969 and the contraflow bus lane on the approach to New York-New Jersey=s Lincoln Tunnel in 1970 represent the first freeway HOV applications in the country. Today there are some 130 HOV freeway projects in 23 metropolitan areas in North America, including Houston.
HOV facilities are developed and operated to provide buses, carpools, and vanpools with travel time savings and more predictable travel times to encourage individuals to choose one of these modes over driving alone. The person movement capacity of a roadway increases when more people are carried in fewer vehicles. HOV facilities are usually found in heavily congested corridors where the physical and financial feasibility of expanding the roadway is limited. Supporting services, facilities, and incentives are also used to further encourage individuals to change their commuting habits.
HOV facilities are not intended to force individuals to make changes against their will. Rather, HOV lanes are developed to provide a cost-effective travel alternative that commuters will find attractive enough to change from driving alone to taking the bus, carpooling, or vanpooling. HOV projects typically focused on meeting one or more of the following three common objectives.
Increase the Average Number of Persons Per Vehicle. The travel time savings and travel time reliability offered by HOV facilities offer incentives for individuals to change from driving alone to using a bus, vanpool, or carpool. By moving people, rather than vehicles, HOV projects focus on increasing the average number of people per vehicle on the roadway or travel corridor.
Preserve the Person Movement Capacity of the Roadway. HOV lanes, which may move two to five times as many persons as a general-purpose lane, have the potential to double the capacity of a roadway to move people. Also, the vehicle occupancy requirements can be raised if a lane becomes too congested, helping to ensure that travel time savings and travel time reliability are maintained.
Enhance Bus Transit Operations. Bus travel times, schedule adherence, and vehicle and labor productivity may all improve as a result of an HOV facility, helping attract new bus riders and enhancing transit cost effectiveness. Many transit agencies have expanded or initiated express bus services in conjunction with HOV facilities.
Managed lanes are also used in some metropolitan areas and are being considered in other regions. The Interstate system, which was developed to provide high-speed travel with limited access, represents the most common example of managed lanes. More recently, managed lanes have reemerged in new and different ways in urban areas throughout the country.
There is no one common definition of managed lanes. The term managed lanes is being used in many areas to describe facilities or lanes developed and operated in special ways. Managed lanes may focus on serving special user groups, such as HOVs or trucks; value pricing or tolling options; express lanes; and limited access facilities.
The Texas Department of Transportation (TxDOT) has developed the following definition for managed lanes as part of a research program, and it serves as the official definition of the concept for TxDOT:
"A managed lane facility is one that increases freeway efficiency by packaging various operational and design actions. Lane management operations may be adjusted at any time to better match regional goals."
The Washington State Department of Transportation (WSDOT) developed the following definition of managed lanes in a 2001 workshop.
"Managed lanes facilities include any roadway lane that can be managed to prevent congestion from occurring. In managed lanes, one or more of these techniques is used to control the number of vehicles using the lane or roadway:
- Limiting access – providing infrequent on-ramps, as on the I-5 and I-90 express lanes;
- User eligibility requirements – such as HOV-only, truck-only, permit-only; and
- Pricing – tolls can be varied by time of day to control traffic volumes.
By considering these as different forms of traffic management, it is possible to plan the best combination of tools to keep a roadway from becoming congested over time, and to optimize traffic to achieve the best person and vehicle throughput."
Although other definitions are being used in different states and areas, all focus on better management of a new or existing facility by targeting a range of possible strategies and user groups. The following facility types and strategies are typically included in general definitions of managed lanes focusing on preserving enhanced travel conditions:
- HOV lanes;
- high-occupancy/toll (HOT) lanes;
- value-priced lanes;
- express lanes;
- separated or bypass lanes;
- truck or commercial vehicle lanes;
- dual roadways, such as physically separated inner and outer roadways in one or both directions where operation can be managed on at least one of the roadways; and
- separate toll lanes constructed within freeways.
From the late 1940s through the mid 1970s, the Houston metropolitan area grew at a rate well above the national average, increasing in population from less than half a million to over two million. For most of this period, highway and street construction kept a reasonable pace with growth. By the mid 1970s however, traffic congestion was a significant concern. During the same period, the city was considering options to purchase the privately owned bus company, which was reducing service and maintenance levels in the face of financial hardships. The use of what was then a relatively new and untried concept – high-occupancy vehicle (HOV) lanes &38211; was considered to address these concerns, and an initial demonstration project on the I-45 North Freeway was undertaken.
Today, some 4.3 million people live in the 8,800-square mile Houston metropolitan region, which is characterized by low-density development, typical of southwestern cities. In response to ongoing concerns related to traffic congestion on the freeway system, limited available right-of-way, and air quality, the initial nine-mile contraflow demonstration project has evolved over an almost 25-year period into a system that encompasses some 100 miles of HOV lanes, numerous direct access ramps, 28 park-and-ride lots, four park-and-pool lots, an extensive network of express bus service, and a value pricing demonstration project. This system provides preferential treatment to buses, vanpools, and carpools in the major freeway corridors.
The HOV system represents part of a multifaceted approach being taken in the Houston area to manage traffic congestion and to improve mobility. Building on the success of the HOV system, a value pricing demonstration was initiated in two corridors and managed lanes are being developed in one corridor. Other improvements to the surface transportation system include expanding freeways and roadways, building new toll roads, and developing an advanced transportation management system (TranStar). A light rail transit (LRT) line is also under construction and will open in early 2004. Future plans include additional HOV facilities, considering managed lanes in other corridors, expanding the LRT system, examining commuter rail, additional toll roads, and expanding TranStar.
Planning, designing, operating, and enforcing the HOV system elements has been accomplished through the coordinated efforts of the Texas Department of Transportation (TxDOT) and the Metropolitan Transit Authority of Harris County (METRO). Recently, Harris County and the Harris County Toll Road Authority (HCTRA) have joined this partnership to assist with the development and operation of the planned managed lanes. These efforts have been coordinated with the Houston-Galveston Area Council (HGAC), the metropolitan planning organization (MPO) for the area.
The HOV system has attracted new riders to transit and ridesharing and has influenced commuters to change from driving alone to using an HOV mode. This report highlights the development and the use of the Houston HOV and managed lane system. The institutional arrangements supporting the development and the ongoing operation of the system are summarized. The issues that may be encountered with managed lanes area also highlighted.
A number of activities were completed as part of this study. First, available reports, papers, and other documents on the Houston HOV and managed lane facilities were reviewed. The HOV system has been the focus of ongoing monitoring efforts supported by TxDOT and METRO. As a result, a good deal of information is available on the use of the system. Second, additional information was obtained through communication with representatives from agencies and organizations in the Houston area. No further original data collection was conducted due to the limited project scope. Third, information from the Houston case study was synthesized and combined with information on managed lanes in other areas to highlight some of the issues typically associated with HOV and managed lanes.
The remainder of the report this divided into three chapters. The evolution and use of the various elements of the HOV and managed lane system in Houston are presented in Chapter Two, along with possible future plans and projects. The institutional arrangements associated with the development and operations of the system are described in Chapter Three. The elements and issues typically considered in planning, designing, implementing, and operating managed lanes are discussed in Chapter Four.