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This chapter covers the totality of HOV facilities, inclusive of supportive features, but without examining supportive features in detail. Express bus operations and park-and-ride and park-and- pool facilities are supportive features that enhance the operation of many HOV facilities. These are the subjects of Chapter 4, "Busways, BRT and Express Bus," and Chapter 3, "Park-and- Ride/Pool." OBJECTIVES OF HOV FACILITIES The primary and interrelated goals of HOV facilities are to provide buses, carpools, and vanpools with travel time savings and more predictable travel times, and to thereby induce individuals to choose a higher occupancy mode over driving alone. Supporting services, facilities, and incentives are often used as further encouragement for significant numbers of individuals to change their commuting to a more cost-effective, higher-occupancy travel alternative. The person movement capacity of the roadway is increased when more people are carried in fewer vehicles. HOV facilities are usually found in heavily congested corridors and areas, frequently with heavy bus volumes. Typically the physical and financial feasibility of expanding the roadway is limited. HOV projects have largely focused on meeting one or more of the following three objectives (Turnbull, 1992a): Increase the Average Number of Persons per Vehicle. Travel time savings and travel time reli- ability offered by HOV facilities offer incentives or reduce disincentives for individuals to change from driving alone to using a bus, vanpool, or carpool. HOV projects focus on moving people, rather than vehicles, by increasing the average number of people per vehicle on the roadway or travel corridor. Preserve the Person Movement Capacity of the Roadway. An HOV lane, which may move two to five times as many persons as a general-purpose (GP) lane, has the potential to double the capacity of a roadway to move people. The vehicle occupancy requirements can be raised if a lane becomes too congested, to help 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 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, to attain a flexible, easily staged, and relatively low cost form of high capacity express transit. TYPES OF HOV FACILITIES AND TREATMENTS The various types of HOV facilities, treatments, and programs are characterized here to establish a discussion framework. Unless otherwise noted, examples are provided later in this chapter in the corresponding "Response by Type of Strategy" sections and tables. Busways or HOV Lanes in Separate Rights-of-Way. This approach to providing HOV priority uses roadways or lanes developed on alignments mostly separate from the highway 2-2

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system. Existing projects are two lane, two direction facilities for buses and special permit vehicles only, like the busways of Pittsburgh and Ottawa, Canada. This type of facility is not addressed in this chapter. Examples and information related to traveler response to transit services operated on such facilities are found in Chapter 4, "Busways, BRT and Express Bus." Exclusive Freeway HOV Lanes. Exclusive freeway HOV lanes include both two-directional HOV lanes and reversible HOV lanes. Both types are constructed within a freeway right-of-way, are physically separated from the GP (mixed traffic) freeway lanes--typically by barriers or wide buffers--and often have direct access ramps. Exclusive two-directional facilities serve traffic flow- ing in both directions at the same time. Reversible HOV facilities operate inbound toward the cen- tral business district (CBD) or other major activity center in the morning and outbound in the afternoon. Concurrent Flow Freeway HOV Lanes. These most common of freeway HOV lanes operate in the same direction of travel as the GP traffic lanes and are separated only by normal paint striping or a 2 to 4 foot painted buffer. They are designated for exclusive use by HOVs for all or a portion of the day. Concurrent flow lanes are usually located on the inside lane or shoulder, next to the free- way median, but a few outside HOV lanes are utilized. Contraflow Freeway HOV Lanes. The contraflow lane approach takes an underutilized freeway lane from the off-peak direction of travel, typically the innermost lane, for exclusive use by HOVs traveling in the peak direction. The lane is separated from the remaining off-peak direction GP travel lanes by some type of changeable treatment, such as removable plastic pylons inserted into corresponding holes or moveable concrete barriers. Contraflow lanes are typically operated dur- ing the peak period in the direction of peak flow, reverting back to normal use in other periods. Often they are limited to use by buses only. Ramp Meter Bypasses and HOV Access Treatments. This type of strategy can give HOVs prior- ity at metered freeway entrance ramps by providing either a separate lane located adjacent to the metered GP lane or a separate HOV entrance ramp. Either way, they allow HOVs to move around the traffic queue at the meter or otherwise directly enter the freeway. These techniques may be used in combination with a freeway HOV lane or as a stand alone measure. Direct access ramps from adjacent roadways, park-and-ride lots, and transit stations are also employed in some areas to provide buses, and sometimes vanpools and carpools, with extra travel time savings and trip time reliability. Changes in Occupancy Requirements and Operating Hours. Changing vehicle occupancy requirements is an HOV lane demand management strategy that involves modifying the HOV lane use eligibility requirements. The occupancy requirement may be lowered to encourage use, such as from three persons per vehicle (3) to two persons (2), or may be increased to mitigate HOV lane congestion and preserve HOV travel time advantages. Changes in hours of operation alter the balance of time allocated to HOV priority--usually peak-travel periods at a minimum--as compared to time when the facility reverts to GP lane status, giving all vehicles equal access. HOV Facility Exempt Vehicle and Value Pricing Programs. These various programs have been tested in one or more areas, some on a strictly experimental basis and a number moving into continuing status. Most are designed primarily to manage demand on existing or new HOV lanes to attain higher lane utilization than might otherwise be possible. Exempt vehicle programs allow qualified vehicles with a valid sticker, license plate, or automatic vehicle 2-3