The Iowa Department of Transportation (Iowa DOT) sponsored the Center for Transportation Research and Education (CTRE) conduct of research on the capacity and driver merge behavior at Interstate work zone merge areas. The principle goal of this research is to determine the traffic capacity at work zone locations where two lanes of traffic are reduced to one (lane closure). Reducing two traffic lanes to one in each direction is the typical method of channeling traffic into a work zone on Iowa's rural Interstate system. When traffic volumes exceed the capacity of these merge points, the resulting congestion can lead to the formation of queues, which result in delays and increases the potential for traffic crashes. Successful implementation of work zone improvements at locations where congestion is expected will provide a benefit to motorists through reduced delays and increased safety. The research project was conducted in four phases: a literature review, the collection of traffic data at work zone merge areas, the analysis of this data, and the development of a computer simulation tool to model traffic at merge areas.

To support the analysis of driver behavior at rural freeway work zone lane closure merge points, Center for Transportation Research and Education staff collected traffic data at merge areas using video image processing technology. The collection of data and the calculation of the capacity of lane closures are reported in a companion report, "Traffic Management Strategies for Merge Areas in Rural Interstate Work Zones". These data are used in the work reported in this document and are used to calibrate a microscopic simulation model of a typical, Iowa rural freeway lane closure. The model developed is a high fidelity computer simulation with an animation interface. It simulates traffic operations at a work zone lane closure. This model enables traffic engineers to visually demonstrate the forecasted delay that is likely to result when freeway reconstruction makes it necessary to close freeway lanes. Further, the model is also sensitive to variations in driver behavior and is used to test the impact of slow moving vehicles and other driver behaviors. This report consists of two parts. The first part describes the development of the work zone simulation model. The simulation analysis is calibrated and verified through data collected at a work zone in Interstate Highway 80 in Scott County, Iowa. The second part is a user's manual for the simulation model, which is provided to assist users with its set up and operation. No prior computer programming skills are required to use the simulation model.

One of the ways a state department of transportation or other transportation agency can address work zone safety and other impacts is to develop and implement a Transportation Management Plan (TMP). The TRB National Cooperative Highway Research Program's NCHRP Research Report 945: Strategies for Work Zone Transportation Management Plans provides a practitioner-ready guidebook on how to select and implement strategies that improve safety and traffic operations in roadway construction work zones. Supplemental materials to the report include NCHRP Web-Only Document 276: Evaluating Strategies for Work ZoneTransportation Management Plans; fact sheets on ramp meter, reversible lane, and truck restrictions; and guidebook appendices.