Construction activities and numbers of related work zones on urban freeways have grown significantly. The most problematic work zones occur on roads that are already fully loaded, and impacts of work zones on mobility and fuel efficiency make success of the traffic control plan vital. Full freeway closures are sometimes implemented to expedite project completion and thereby reduce the cumulative impact of construction on travelers; however, full closure can cause significant freeway congestion. Congestion costs American drivers more than $100 billion each year in wasted fuel and lost time. Reducing work zone congestion can be an effective energy conservation technique that not only saves fuel but also saves traveler time. If a work zone plan includes freeway closure, an effective diversion plan that makes drivers aware of delays and available alternate routes can help minimize congestion. Construction on the SH-71/IH-35 interchange required complete closure of all IH-35 main lanes. IH-35 is an important business corridor, conveniently connecting four large Texas cities and facilitating trade between Mexico and the United States. A parallel route, the SH-130 toll road, was made free to travelers during those closures. The purpose of this paper is to investigate driver route-switching behavior during the IH-35 closure and how that behavior reduced fuel consumption and explored options for relieving delays on IH-35 during future closures. The findings indicate that changes in traffic volume on SH-130 during the closure were statistically significant, although usage of SH-130 was less than anticipated and there was significant queuing on IH-35 at the work zone. Analysis was based on integrating data from all available sources. Traffic conditions of a nonclosure weekend were compared with the closure weekends, and fuel consumption was estimated.