Conducting a full operational analysis of freeway facilities is a challenging undertaking, as most available methods either lack the necessary detail for specific geometry and demand patterns, or are very data and cost-intensive to implement. For the past few years, NCDOT has been using a customized software application for conducting in-house analyses of freeway facilities, with a special emphasis on work zones. The analysis methodology and associated software tool, FREEVAL-WZ, were deliverables from a prior NCDOT research effort (2010-08). The methodology is founded on the analytical method for evaluating freeway facilities in the most recent Highway Capacity Manual, but has been enhanced to incorporate work-zone analysis details, as well as some state-specific defaults for its application in North Carolina.
While that prior research accomplished its objectives and produced a tool that is used by NCDOT analysts today, several critical extension needs to the methodology have been identified by NCDOT staff through the use and application of the tool in day-to-day practice. Further, several areas of future research had been identified in the final report of project 2010-08. This proposal is targeted at filling these identified gaps, as well as addressing the suggested areas of research and development for planning-level freeway work zone analysis for NCDOT.
The particular focus of this project is on implementing a series of planning-level analysis extensions to the methodology. Planning-level freeway (work zone) analyses are oftentimes performed in a “data poor” analysis context, where the available data is limited to basic freeway geometry characteristics and daily traffic demand patterns. Detailed peak-hour volume estimates are oftentimes not available at the early stages in a project. Further, in a planning-level application for work zones, a key decision of interest is when to close lanes and for how long, which ultimately calls for a full-day analysis context. Finally, customized output reports are needed to present key performance metrics in a standardized and readily usable format.
The results of this research will help analysts in the NCDOT Safety and Mobility Division to explore the operational performance of freeway facilities in a planning-level context, by conducting additional freeway work zone research, and by significantly enhancing the capability of the existing FREEVAL-WZ tool. The research will benefit analyses with and without work zones by enabling full-day (24-hour) analysis, improved volume estimation, and enhanced usability, including specifically-targeted output reports for different groups within NCDOT.
