California’s State Route 39 once connected the San Gabriel Mountains to the Pacific, but a 1978 rockslide forced the closure of its final 4.5-mile section—an eerie, scenic road that’s never reopened.

Just north of Los Angeles lies a highway with no through traffic, no guardrails—and no easy return. California’s Highway 39 has been closed for over 40 years after a rockslide severed it from the rest ...

The highway expansion plans have become a point of contention between environmental groups and labor unions. California transportation officials approved funding for six highway construction projects ...