This synthesis will be of interest to transportation planners, highway engineers, environmental personnel, highway design engineers, transit planners, highway administrators, and others concerned with the planning, design, and operational features of preferential high- occupancy vehicle (HOV) lanes on highways. Information is provided on the current and proposed state of the practice in North America. This synthesis describes the state of the art with respect to preferential treatment for HOVs on highways. This report of the Transportation Research Board provides information on long-distance facilities, such as barrier-separated, concurrent-flow (separated and nonseparated), and contraflow facilities, as well as on short-distance facilities, such as queue by-pass lanes. Planning, design, and operational features of each treatment are described. The issues and operating results are described, and specific case studies are included.

Enforcement of high-occupancy vehicle (HOV) traffic restrictions forms an integral and sometimes critical element of HOV preferential treatment projects. This research (1) reviewed enforcement on HOV facilities, (2) identified effective HOV enforcement techniques, (3) developed model legislation for effective HOV enfoorcement and (4) prepared HOV enforcement guidelines. This report presents the findings of this research. Sixteen projects in the United States encompassing each type of freeway and arterial treatment, were visited to gain in-depth operational and enforcement data on each project.