Funding sources: Caltrans and US DOT

Contract numbers: Caltrans: 65A0674 and US DOT: 69A3551747109

Funding amounts: Caltrans: $78,837 and US DOT: $21,803
Performance period: 08/16/20 to 08/15/21

We use four data sets to study supercommuting in the San Francisco Bay Area and Central Valley of California. We follow previous research in defining supercommuting as commutes longer than 50 miles or 90 minutes one-way. The San Francisco Bay Area has some of the highest housing costs in the United States, and anecdotal evidence has long suggested that households might move from the Bay Area to Central Valley counties, possibly enduring long commutes if they cannot move their job at the same time. Yet evidence on a link between supercommuting and house prices has been limited by data availability. We use the data first to demonstrate that the supercommute is far from uncommon, with some Central Valley counties having supercommuting rates that approach 10 percent of all county commutes. We use data on household moves, from zip code tabulation area to zip code tabulation area (ZCTA to ZCTA), to examine how supercommuting rates at the ZCTA level are linked to flows of in-migration from the Bay Area into the Central Valley. We find evidence that suggests that ZCTAs with higher in-migration flows from the Bay Area have higher supercommuting rates.