California Partners for Advanced Transportation Technology

There is increasing interest in building new high occupancy toll (HOT) lanes and in converting high occupancy vehicle (HOV) lanes with unused capacity to HOT lanes.  Like HOV lanes, HOT lanes provide an incentive for travelers to use HOVs, but unlike HOV lanes, they can always be well utilized by varying the toll over the congested period, thus providing more congestion relief than an HOV lane with unused capacity.  This report provides guidelines regarding the circumstances in which HOT, HOV, and mixed flow lanes are most appropriate.  Using a queueing model combined with a mode choice model, the reduction in delay from adding an HOV, HOT, or mixed flow lane to an existing three-lane freeway was estimated for three levels of initial HOV use and three levels of initial delay.