Happy transit systems are all alike; every unhappy transit system may be unhappy in its own way. Case in point: Southern California.

Los Angeles County, the most populous in the country, has been dramatically expanding rail transit connections for its 10 million residents. Yet across L.A. and five other counties that make up the heavily urbanized Southern California region—Orange, Riverside, San Bernardino, Ventura, and Imperial—ridership on public transportation systems has mostly declined since…