I had an OWI and a possession under age about two years before applying. Based on my numbers, the T2 schools I applied to just let me in right away. The T1 schools I applied to both waitlisted me. I managed to get in off the waitlist at one of the T1s by meeting with the dean of admissions and basically just showing him that I had changed. This school was unique though, so I'm not sure a meeting with the dean is realistic at most schools. That's something to consider though if it is possible for you.