On average, Los Angeles residents smoke less, work shorter hours and face far fewer cloudy days -- a proven mood booster.

But they also spend a lot of time stuck in their cars, thanks to gridlock that is among the country's worst. And unlike many other places, L.A. doesn't offer many major public transportation alternatives that help them escape those traffic headaches.

There are projects aimed at fixing that. The Los Angeles Metropolitan Transportation Authority is pushing forward with five additions to the area's mass transit network, including the long-awaited "Subway to the Sea." Meanwhile, Caltrans is spending billions on freeway improvements, including adding and extending carpool lanes.

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"If we can get people to participate in carpooling we can try to reduce traffic and improve the air quality," said Caltrans spokesperson Patrick Chandler.

Living in the city is also pricey, which makes it even harder for the 20% of residents who live below the poverty line to get by.