IHigh-Occupancy Vehicle Treatments on Arterial Streets

O of the most successful transportation systems management (TSM) actions in recent years has been the priority treatment of high-occupancy vehicles (HOVS), The priority treatments typically have been either the provision of dedicated through-travel lanes or queue bypass lanes at roadway capacity restrictions. Through the use of priority measures, HOVS (buses, vanpools and carpools) are given two significant advantages: travel time savings and trip time reliability. These two benefits are the primary incentives used to encourage a shift from the single-occupant vehicle to the ridesharing and public transit modes. The current experience with HOV facilities on arterial streets has been limited compared to those on freeways. The majority of arterial street HOV facilities have been bus-only lanes in the downtown or central business district (CBD) area. An earlier study located the first arterial street bus-only facility on North Sheridan Road in Chicago, 111.,in 1939, and identified 40 other similar arterial bus-only priority projects.l Few significant arterial street HOV projects have been initiated since the mid-1970s energy crisis and many have since been suspended for a variety of reasons ranging from low utilization to enforcement problems.2 Few of these projects have permitted the operation of carpools or been located in a suburban environment. Increasing congestion at suburban activity centers and the recent successes of freeway HOV projects have prompted an awareness of the need for arterial street HOV facilities that permit carpools and vanpools as well as buses. Many transportation professionals, however, have noted the absence of guidelines for HOV facilities on arterial streets. This article contains a discussion of the major issues associated with arterial street HOV facilities that is centered around three generic environments where HOV treatments might be considered: CBD streets, freeway-to-arterial HOV system connections to major activity centers and line-haul arterial streets. Each environment has distinguishing area and travel characteristics, each has a somewhat different set of issues associated with it and each requires a unique HOV approach with different design and operation alternatives.