Gary Ritter U.S. Department of Transportation, Ret. Beginning in the 1970’s, and more aggressively since the late 1980’s, the U.S. DOT has pursued an ongoing research agenda to better inform traffic and travel decision making through the application of Intelligent Transportation Systems (ITS). Over the past two and a half decades, some five billion dollars have been allocated toward ITS research, development and field testing activities, much of which targets various methods and means of improving traffic and travel decision support to further the public good. In this talk, major ITS findings will be summarized, along with practical challenges that pose ongoing impediments in market-driven traffic decision support innovation. Experiences in SafeTrip-21 (Safe and Efficient Travel through Innovation and Partnerships in the 21st Century) field tests conducted during 2008-2010 will be highlighted, along with traffic decision support implications of connected and automated vehicles.