Should I get roller blades or a bike?

I would go with a bike. Just get a combination or key lock for it, and it won't get stolen. For one, a bike will be faster in the long run, and reguardless of whether you're riding your bike or roller blading, the traffic and cars on your route aren't going to change. Also, carrying roller blades around campus seems unnecessary and hard. They aren't small, and even if you can fit them into your backpack, they will probably take up a lot of space. Where as a bike, you just lock up when you get there and go get it later on when you're ready to leave and go home. Another suggestion is have you thought about a longboard?? They are meant more for travel than a skateboard, and aren't very hard to learn.

A bike. I know somebody who got made fun of for roller blading to school and they're more difficult to learn. To keep your bike safe, get a lock and chain for it.