The Kelker & DeLeuw Subway Plan is gradually rolled out in 1925 after voters narrowly ignore entrenched interests' opposition. Due to this type of forward thinking, 90% of the subway system is completed by the time mass transit is transferred from the private sector to the public in the 1960s.
Henry Huntington is forced to give up some of his streetcar routes to Southern Pacific so there'd be competition. When all streetcars are handed over to MTA, only the easternmost suburbs see buses supplant routes.
Maglev right of way is in place between Ontario Airport and west Los Angeles but funding is still scarce.