For about two years now London has been experimenting with commuter bikes. These are rented using a special credit card and can be taken and returned from various racks around the city.
These were parked close to St. Paul's and the lot seemed pretty full. I wonder what happens if you arrive at a rack and find it full, do you have to cycle off somewhere else to find a vacant slot?
The bikes are very easy to spot with their Barclay's Bank panel on the rear fender, and I believe they are quite heavy. I lifted up the back wheel and they seemed OK, but that's not a very good test. The incidence of theft has been extremely small.
I wonder how successful such a scheme would be in Los Angles. Perhaps you could have them on the outside near Metro stations so that people could drive to the outskirts and then cycle on for the rest of the commute.
It would be an interesting idea for the city.