Transportation agencies are faced with growing challenges of congestion and a limited ability to expand freeway capacity due to environmental and societal impacts. Transportation officials are taking advantage of opportunities to address mobility needs and provide travel options through a combination of limited capacity expansion and operational strategies designed to manage travel demand, improve transit service, and support other forms of ridesharing. The managed lane concept is gaining interest around the country as an approach that combines these elements to make the most effective and efficient use of a freeway.
High-occupancy vehicle (HOV) lanes have been in existence since 1969, and the introduction of high-occupancy toll (HOT) lanes in the 1990s has added another alternative for highway. Researchers have suggested that in some areas, HOV lanes do not function properly, in that the lanes operate below capacity or the lanes become congested like their general purpose lane counterparts. HOT lanes promise to make better use of existing HOV lanes, to provide capacity more efficiently than either conventional HOV lanes or general purpose lanes, and to reduce the number of lanes needed on new freeways by managing demand. Other than demand management, HOT lanes provide a choice with reliable and shorter travel time for whoever is willing to pay the toll. In many cases, toll revenues are used for the conversion of a HOV lane to a HOT lane or investment in transit rather than generating funding sources. As of 2013, 18 HOT facilities are under operation in the US, and more than 11 HOT facilities are under construction.
