Say the words "Los Angeles," and you might conjure visions of epic traffic jams, air pollution so thick you can't see the hills, and a city that seems designed to intimidate and marginalize pedestrians and bicyclists. But a new reality is emerging in the city of angels. A slew of developments over the past decade is helping the world capital of car culture transform itself into a world leader in sustainable transportation. While traffic is still bad, the air is significantly cleaner, and public transit alternatives are expanding. If the trends continue, L.A.'s transportation sector could become a model for California -- and the nation -- as we struggle to end our dependence on oil.