Originally Posted by repechage

I live in Southern California.
For the commute described, and the eventual end of daylight savings time, plus the overall poor condition of LA City streets, I would be looking at a rigid mtb. Exchange the quick release seat binder bolt for a bolt.
Consider where you will be parking, at say school, repeat parking during the week, for extended periods...the strongest U lock you can afford, yes the better ones are not cheap. I would really look to see if there is a low risk parking option, even a cheap bike being stolen can really stand you.

When I ride to my Dr., a 25 mile jaunt each way, I park in the building in easy view of the parking attendant. Ride a mtb, long shadows in the morning can really hide dangerous road surfaces. Almost lost it on Lincoln Blvd once, near Venice Blvd at a bus stop, there literally was a 9" abrupt drop in surface where the plane changed as well, there was another commuter behind me and we met at a signal later, he stated " you don't ride this often, do you?"
It's a dangerous world out there.