Department of Economics

Falling Roads and Rising Times: Commute Time and Mode Analysis Following a Bridge Collapse

Research completed by Eric Tubbs

Abstract of research: Estimates suggest that three quarters of Americans commute to work in their cars every day, representing millions of twice daily trips with an average time of 27 minutes. Commuting costs to the commuter include out-of-pocket automobile and fuel costs as well as opportunity costs in terms of time. This paper asks how sudden changes in road infrastructure affect commute times and how quickly do commuters adapt to such shocks by adapting to a different commute mode. This paper presents an econometric analysis of commute time and mode following the collapse of the I-35W Mississippi River Bridge of Minneapolis, Minnesota. A difference-in-differences model was used to estimate the changes that the bridge collapse caused in the duration of local commutes as well as in the choice of commute mode. Additionally, attention was paid to the different impacts that the bridge collapse had on across gender, racial, and income in the Twin Cities Metropolitan Statistical Area.