I've been commuting by bike in LA 3-4 days a week for like 6 years. I actually don't mind it. As it stands right now, I'm going 12 miles each way. At a previous job, I was going 17 each way.
I should caveat that. I was riding up the bike path along the beach form the South Bay most of the way of that 17 miles, but would cut into Venice/Santa Monica from the bike path and take neighborhood streets from there.
As it stands right now, I'm going from El Segundo to North Culver. I ride the Ballona Creek trail almost the entire way, over the course of the 12 miles, I see 4 stop lights. Again, I avoid La Cienega like the plague, and stay on neighborhood streets.
I'm also lucky enough to have always had access to a shower at any of my jobs. If it wasn't for that, I think anything over about 6 miles would do me in. A bird bath isn't the worst thing in the world.
I was hit once pretty hard by a driver, which destroyed my bike and put me in the hospital, but I'm no worse for the wear, and I would still rather ride than sit in the car. Especially given it takes the same amount of time.
You can check out a post about it: http://wafflesonwednesday.com/wisdom-fr ... commuting/
Words to the wise:
Stay off the main streets. Usually there's a street that runs parallel to where you're trying to go with way less traffic, so take that one, even if it's a little longer. Don't be afraid to end up on the Sidewalk some if you need to.
Get gatorskin tires. They've saved me a ton of flats with all the garbage in LA.
Get some reflective gear, I just use a construction safety vest and I have lights and DayGlow gloves for signaling.
Also, please wear a helmet.
Regardless, people are crazy, drive & ride defensively... And be safe... Hope to see you out there!