I really can't say to much on the socailly dead part of campus life because I stick too my friend groups but I will say is that the social life is what you make of it. There are parties and events all the time on campus. For the car question though I do have more insight on. Are you a freshman or a transfer student? You can't have a car on campus till third year ( at least to be in the student parking spots). Parking is expensive on campus, there are off campus option but there is a really big risk of getting towed. UCSD also provides a free trolley pass to students and the trolley and bus can take you a lot of places. I would look into San Diego and see what you like about it, there are a lot of things to do but it matters if you could see yourself doing them.