Priority-Based High-Occupancy-Vehicle Lane Operation

Federal and State governments are investing billions of dollars and promoting usage of High Occupancy Vehicle (HOV) lanes through various programs. Many states, including California have demonstrated the effectiveness of HOV lanes and are in the process of completing the HOV lane network. However, HOV lane operations continue to be criticized for its underutilization of roadway capacity and limited ability to shift Single Occupancy Vehicle (SOV) drivers to transit and carpools. Hence, many states are considering the conversion of HOV lanes to other type of operation. Ten states in the US have considered allowing single occupant hybrid vehicles (SOHV) into HOV lanes to encourage the purchase of hybrids and reduce the fuel consumption and congestion in both HOV lanes and general purpose lanes. In addition, High Occupancy Toll (HOT) operation is being considered as a good alternative to make better use of HOV lane capacity and at the same time generate revenue that can be used to improve transit and other transportation facilities within the corridor. All the proposed strategies are aimed at better utilization of the roadways and to better manage the multi-modal transportation system. For HOV Operations to be managed in an efficient way, a usage priority system must be developed. To improve the current HOV lane operation, this paper proposes a priority based HOV operation strategy, which manages the productivity of the HOV lanes by controlling the access to HOV lanes based on dynamic traffic condition and priorities of vehicle types. The strategy is then evaluated in a microscopic simulation environment based on a freeway network in the City of Irvine, California. Simulation results show that the proposed strategy improves 10.3% of total passenger travel time and 6.78% of travel speed. It is also shown that the proposed strategy also has the capability to maintain good traveling conditions along the HOV lanes and at the same time improves the condition along general purpose lanes.