AASHTO GHOV 3rd Edition, November 1, 2004
Guide for High-Occupancy Vehicle (HOV) Facilities
Limited right-of-way and economic realities often dictate that public investments be concentrated toward increasing the efficiency of and preserving the existing transportation infrastructure rather than expanding the existing transportation infrastructure. At the same time, it is likely that growth of metropolitan areas will continue. A major consequence of these trends will be an increasing inability of the existing transportation system to meet future demand. Therefore, alternative measures must be taken to prioritize use, such as moving more people in fewer vehicles.
Various transportation systems management (TSM) tools are available to help achieve increased traffic efficiency on existing transportation systems. Typical examples of TSM tools are: traffic operations improvements at intersections, operational improvements on freeways, improved signalization, and street system controls (one-way streets or reversible lanes).
This guide suggests methods and designs for dedicated facilities to encourage greater use of existing transportation systems, such as increased use of public transit (primarily buses), carpools, vanpools, or other ridesharing modes to help attain the above goals. Guidance is given for planning and design of preferential treatment for high-occupancy vehicles (HOVs). Portions of this guide have been excerpted from the previous edition of this guide, which this new guide replaces (3), the National Cooperative Highway Research Program (NCHRP) HOV Systems Manual (56), and recent research from Texas (18).
This guide has been developed to help achieve the following goals of HOV facilities:
• To provide travel-time savings and travel-time reliability for HOVs;
• To maximize the person-moving capacity of roadway facilities by providing improved operating level of service for HOVs, both public and private; and
• To conserve fuel, improve air quality, and minimize consumption of other resources needed for transportation.
HOV lanes may be provided on freeways and other roadways for the exclusive use of buses and other HOVs so they can bypass peak-period congestion on the general-purpose lanes. Increases in ridesharing can be gained from this option when the time savings are significant. The guide discusses a number of options for the establishment of HOV accommodations.
HOV facilities are usually incorporated into existing highway rights-of-way where width and lateral clearances may be limited. While experience has shown that some variance in design is possible without serious adverse effects on safety and performance, the experiences have not been extensive enough to firmly establish new standards specifically for these types of facilities. Therefore, the values presented in this guide should not be regarded as absolute, but rather as the best guidance available based on experience to date.