Arrive for your interview 5-10 minutes early. Everyone has their watch set differently, and a 5-minute cushion is a good idea. Some interviewers are time-sensitive and notice if you're even one minute late, dulling initial impressions. Don't arrive too early and put pressure on the interviewer if they are not ready for you yet.
Give yourself ample time to reach the location. Rushing will affect your interview performance, so if you think you might be late, call ahead to advise them of the situation.