I once saw a guy sitting down meditating in the middle of an over-crowded footpath in the Sydney CBD. However, if that's not your style...
At night in the dark after everyone's gone to sleep sitting on your bed is good, too. (or in the early morning) You might want to invest in some earplugs if the traffic noise is very bad.
Is there a monastery or Buddhist organisation near where you live where laypeople can use the facilities? Does your college/university have a multi-faith prayer room? Might be worth a look, at least to see if anyone actually uses it besides Muslims. Or, if you're happy to meditate on a pew, there's nothing stopping you from using churches which are open to the public for contemplation (if you have such churches where you live).
You could try less-busy public parks or secluded natural areas, if you're fine with that. (Personally, I'm not.)
Or acquire a Buddhist friend and go to his or her house. ^^ <- I like this idea best. Kalyanamitta.
I'm not very good at right speech, although I try, so please guide and correct me if necessary so I don't make bad kamma for myself and cause others to be annoyed. (=