UC Davis Institute of Transportation Studies

The Fix I-5 project was an engineering project that rehabilitated drainage and pavement on Interstate 5 in downtown Sacramento, from May 30, 2008 to July 28, 2008. In order to alleviate congestion, media outreach alerted commuters about projected traffic conditions as well as advised alternative modes or routes of travel. The construction schedule included complete closures of north or southbound portions of Interstate 5. This study analyzed the impact of the Fix I-5 project closures on peak period bus transit ridership of five transit agencies serving the downtown Sacramento core. The results indicated that gasoline prices and unemployment rates were statistically significant predictors of transit ridership, with increased gasoline prices and unemployment related to increased bus transit ridership. All agencies had overall increases in mean ridership during the study period, but there were also seasonal variations in mean ridership. Removal of trend and seasonal components in the bus transit ridership data sets was accomplished using multiple regression and sinusoidal decomposition. Time series intervention analysis then estimated that the Fix I-5 project had little impact on mean number of bus riders for all five transit agencies. Bus transit agencies with main service areas closest to the Fix I-5 project were most affected, with ridership increases of about three percent or less attributable to Fix I-5. This study did not analyze the impact of Fix I-5 on other modes of transportation, which may have been more affected than bus transit ridership.