The Virginia Department of Transportation (VDOT) uses probe vehicle data from different sources to measure highway system mobility performance at both the macro- and microlevels. VDOT uses delay as the key metric for macro-level performance measurement and measures both recurring and non-recurring delay at the statewide, district, and corridor levels. The sources of non-recurring delay include traffic incidents, work zones, weather events, and holiday travel. VDOT’s micro-level performance measurement uses more granular probe vehicle data to measure queues, queuing patterns, and travel time at the individual project-level on selected projects. The data and information are used to identify macro-level (e.g., corridor-specific) and micro-level (e.g., project-specific) contribution to delay, the underlying issues and root causes, and areas and opportunities for improvement.
Work zone mobility is a key focus area for VDOT’s performance measurement program. By measuring work zone mobility performance at the project, road segment, corridor, district and statewide levels, VDOT is not only able to report performance on an annual basis but also analyze trends and patterns year-over-year and over time. Further, by segmenting and aggregating performance measures at the individual-project level and the macro-levels, VDOT gains a comprehensive bottom-up and top-down view of work zone performance. VDOT’s work zone and traffic control practitioners use the intelligence gained from these efforts to improve project-level work zone management practices and broader agency, district, and corridor-level work zone policies and procedures.