 This paper examines how changes in commuter behavior could affect travel times in U.S. metropolitan areas. It uses data from the American Community Survey to identify the sensitivity of commute travel times to changes in vehicle usage. The authors also develop a model to predict the effect of different levels of vehicle usage on travel times. They find that the most affected areas are those that are already congested and have high transit ridership. In these areas, a 25% reduction in transit and carpool use could lead to a 12-minute increase in round-trip travel time, which would cost individuals slash bin slash SH65 dash slash bin slash SH60 per day in lost time. However, if people were encouraged to work from home, this could reduce the need for increased vehicle usage and thus reduce travel times. This article was authored by Yoo-Hoo, William Barber, Ko-In-Chen, and others.