SP double-tracked the line in 1904 and rerouted it via the Bayshore Cutoff. After 1945, ridership declined with the rise in automobile use; in 1977 SP petitioned the state Public Utilities Commission to discontinue the commuter operation because of ongoing losses. California legislators wrote Assembly Bill 1853 in 1977 to allow local transit districts along the line to make bulk purchases of tickets for resale at a loss, subsidizing commuters reliant on the Peninsula Commute until 1980; more importantly, the bill also authorized the California Department of Transportation (Caltrans) to begin negotiating with SP to operate the passenger rail service and acquire the right-of-way between San Bruno and Daly City.