Ann Arbor rates quite low on the risk for violent crimes. On the other hand it rates at least at the national risk level for Robberies and Arsons. Luckily, those two crimes are not ones which affect tourists very offer and the actual victims tend to be corporations and industries.
Ann Arbor does have nearly 100 registered sex offenders which is not good news for tourists with kids. (see the website below for more info about that).
So overall, you get a mixed message about how safe Ann Arbor is. Just use common precautions like remembering to lock car doors and keep an eye on the children and you should be as safe as we were in our visit.
The good news is that the city government has expanded its crime task force and over the last five years the crime index for Ann Arbor has been gradually generally declining to a safer level.
Ann Arbor has one of the best public bus systems in the WORLD- unfortunately sometimes you run into a few ruffians on the buses but they're far and few between. I've heard a few instances of some homeless folks hassling riders at the blake transit center.
also, if you ride the bus during rush hour- expect to deal with large gaggles of teens on the bus. Unfortunatly some of them can get a little loud and rowdy and usually the bus driver won't set them straight. just be warned in case you were expecting a nice quiet bus ride.
other than that- AATA is awesome.
If you're driving in Ann Arbor and don't know the area, pay close attention to the street signs. About a third of the streets downtown are one way streets and a lot of lights have no left turns. Just a few days ago, I almost got hit by someone who turned the wrong way down a one way street.
If you're going to Ann Arbor in April be aware of the annual traditions of the undergraduate students (and anyone else that might wander in from Detroit metro.)
During Hash Bash there is an abundance of Mary Jane smoked freely on campus as part of a rally for legalizing marijuana. Google "ann arbor hash bash" for event time/dates.
A tradition started by the men's crew team occurs April 1st each year. Hundreds of students run naked through campus. Google "ann arbor naked mile" and most likely you'll just get a bunch of sites with pictures.
Make sure to park in a legal spot and put those quarters in the meters! Ann Arbor cops are rabid with regard to writing parking tickets! 'Must get a bonus based on ticketing! Art fair is their dream time, too!
Be careful who you ask for directions. Many locals are grumpy about tourists and
will direct you to 'turn East on Washtenaw and keep going.' Some people who have
asked for directions to Zingerman's Delicatessen have vanished without a trace.