Before the Bay Area Rapid Transit system came into being, San Francisco was served by a private “Key Route” system of buses and light rail, which found itself in increasing disuse as highways and buses took ridership away. The system was dismantled too early, as a postwar boom in population highlighted the need for an even larger public transportation system across the bay. A 1957 report concluded the best solution was a high-speed rail network connecting the city’s various suburbs and center.

On this day, September 11, 1972, ten years after it was approved by voters, the San Francisco BART system opened. In the midst of a shortage of gasoline brought on by the Energy Crisis, the rail system became instantly popular among families, students, and joyriders.

In the first week of service (five days — the system initially shut down for the weekends) an estimated 100,000 passengers rode BART rails. And this was still before most schools started classes. One student recalled he “regularly rode AC Transit [part of the old Key Route system] to get to school and explore the East Bay.” But, he added, “BART expanded my free range of movement. I remember standing in the first car looking through the window at the operator, and amazed how the trains sped up to 80 mph on the elevated right-of-way south of Lake Merritt.”