SR 17 was opened in 1940, replacing several other modes of transportation, including the old Glenwood Highway from 1919 (which still exists in Glenwood), and the railroad which went all the way from Santa Cruz to San Francisco and Oakland. The railroad stopped operating in 1940 and the tunnels that it passed through were sealed soon after. Nearly all the tunnel entrances still exist, but are unusable as the tunnels themselves are collapsed. The rise in the use of automobiles made the railroads unprofitable. The city of Glenwood, founded by Charles C. Martin in 1851, gained notoriety for hot springs in the area. The Glenwood Highway, which passed through town, was deserted when the "New 17" was built, and the town became a ghost of its former self. The town's final resident, Mrs. Ed C. Koch, the great-granddaughter of the founder, died in 1992, and Glenwood is a ghost town.