On major road construction projects, maintaining agencies typically designate detour routes and provide detour information to motorists. In the era of real-time traffic information and in-vehicle route guidance, it is not clear to what extent this detour information is received or followed by motorists. An example is the current project to reconstruct Interstate 20/59 in downtown Birmingham, in which a 1.5 mile segment of the interstate will be completely closed for a duration of over 1 year and resulted in significant traffic diversions. Using data from this construction project and a traveler survey, we will attempt to provide insights into how motorists make detour choices with the abundance of traffic information available to them and assess which aspects of detour planning were most effective in optimizing user travel and reducing system wide congestion. Understanding how and why motorists make detour decisions will help transportation officials make more informed and effective decisions in the future. The ultimate goal of this study is to develop a methodology for creating detour plans that can be used for future construction projects by public agencies across the country.