Canonsburg is awesome - we just moved there. It is a nice community, very safe, but you can call the local PD for more details http://www.canonsburgboro.com.
We feel very safe - we live right off main drag which is Pike. It is a nice town where people of all skin colors live very well together, as should be, and most people we've met are nice beyond belief. Very neighborly. Very family oriented. Hard working Americans living the (middle income) dream. They have several neat annual events like Octoberfest coming up soon. My only complaint about canonsburg is it's lacking restaurants with liquor licenses, big time, but I guess there's a plus there too. I still wouldn't mind a place or two with sidewalk cafe, though! I also think due to big money next door in Peters Twp./Strabane that CSBG will only get better and better...And of course there's Sarris Chocolate (heaven on earth!)