Agree. Maybe you'll be able to manage during your first year but during your second year more than likely you'll be traveling a ton unless for some reason you've been touched by an angel and your fieldwork assignment is a bus ride from your place or class...And you don't need to leave or do house/ site visits. Yes, LA has a public trans system and people do rely on it for a living but considering traffic and the areas it serves the public trans system is disappointedly limited.
Also keeping in mind, that you might be able to work with the field coordinator with not having a car but also it'll be difficult to work with that because it could be easier to work with someone who does already have a car. You have to remember that in LA you will be competing for internships with not only other cohorts in your program but other students in other schools. (ie CSULA, CSULB, CSUDH, CSUF and USC...and they have a crap ton of students) So i don't think you'll have the luxury of picking and choosing...it is free work after all and you need them more than they need you.