Brief history lesson and somewhat optimistic view of the future from The Economist:

In the past 15 years the city has gradually built a skeletal subway and light-rail system. Thanks to some creative local politicking, it can now begin to put flesh on the bones.

Los Angeles' dependence on the internal-combustion engine is often blamed on its sprawling nature. That is misleading. Although the city may lack a central core to rival Manhattan or many European towns, it packs a lot of bungalows and two-storey apartment blocks into each square mile. Whereas other cities gradually give way to cul-de-sacs and extravagant lawns, Los Angeles, hemmed in by water and mountains, stays fairly dense almost to its edges. Indeed, according to the Census Bureau, the 12m-strong metropolis is the most densely populated urban area in America.

This unusual pattern of “dense sprawl” makes it both hard to manage without a public-transport system and hard to build one, says Brian Taylor, who studies transport policy at the University of California. Los Angeles is too densely populated for buses to flow freely. Yet it is too spread out to justify a costly subway system.

For a time, in the 1980s and 1990s, urban ambition trumped fiscal prudence. The city built furiously, creating one subway and two light-rail lines by 1995. But cost overruns and a tunnel collapse strained local patience. In 1998 voters approved a ballot measure barring the use of sales taxes for tunnelling. Congress had already banned excavations in the heavily populated Wilshire corridor, which runs through Beverly Hills, on the ground that it might ignite pockets of methane.

The result is a half-finished system that stops short of one of the city's main commercial districts. It is the equivalent of a New York subway system that does not stop in midtown, or a London underground that bypasses the West End....

But the two politicians responsible for halting the subway have since shifted their stance. Henry Waxman, who pushed for the tunnelling ban, is steering a repeal through Congress. Zev Yaroslavsky, who sponsored the 1998 measure, now believes the attenuated Red Line ought to be extended along the Wilshire corridor.

One reason for the change of heart is that Los Angeles has learned to make other people pay for its pipe dreams. Proposition 1B, approved by California's voters on November 7th, allows the state to issue $20 billion in bonds to pay for transport projects that will almost certainly include new railways in Los Angeles—sticking the state's future taxpayers with the bill. Antonio Villaraigosa, the city's ambitious Democratic mayor, also hopes to get more federal money for subways. Given the changing of the political guard in Washington, DC, he should succeed.

The other change is that the city's gridlock has worsened. A commercial boom in the rail-free Westside, where office vacancy rates have fallen from 15% to 7% in the past two years, has gummed the roads....

So far, the city has struggled to make trains work as well as the humble bus does. Although custom is rising on most lines, an impressively smooth light-rail line that connects Pasadena to downtown Los Angeles still carries just 17,000 passengers on the average weekday. An express bus that runs down Wilshire Boulevard carries more than 40,000.

But buses compete for road space with Angelenos' beloved cars, whereas trains do not. So long as they are paid for—and, perhaps, ridden—by other people, the city's residents seem willing to let the building continue.