Despite wide adoption of HOV facilities by many states, Metropolitan Planning Organizations (MPOs) and cities, there still remain questions on the effectiveness of HOV systems. Among relevant factors that may impact the operation and safety performance of HOV facilities, operation policy and HOV-access configurations are being actively evaluated by Caltrans. One idea under investigation to improve HOV lane operation is to reconfigure the HOV lane system from Full-time Buffer-separated to a Full/part-time continuous-access facility. Furthermore, a recent study aimed at evaluating safety performance of California freeways equipped with HOV facilities led to an interesting conclusion—notably, the safety performances of the buffer-separated, limited-access HOV lanes typically seen in Southern California, when compared to those continuous-access facilities, limited-hour operation of HOV in Northern California, appear to offer no safety advantages. This is contrary to the common belief that buffer separation and restricted entrance and exits will provide additional protection for traffic moving in the HOV lanes. As a result, whether to support the idea to reconfigure the HOV lane system from Full-time Buffer-separated to a Full/part-time Continuous-access facility depends on whether or not the continuous-access HOV facility can provide better operational benefits than the buffer-separate HOV facility. This research is designed to address this issue by providing a methodology based on combined real-world data evaluation and simulation analysis to derive further understanding and insights for future policy setting and operational guidelines for HOV facilities, with the ultimate goal of achieving efficient and safe highways.