There are lots of rules and regulations for SUVs and trucks and they are all on the provincial government website under the Highway Act. There is stuff about headlight height, mudflaps, mirrors, brake lights, etc. However, you ask most city police and they don't really know too much about these regulations. The ones you have to look out for are the highway police.
A couple years ago, there was a checkstop out at prairie creek and I know a couple guys that got mudflap tickets, but they are few and far between. Most Jeeps, as long as they look decent are ok, but if you are running 8" of lift and 31s, you might want to look out.
For the record, tires have to be completely covered by the body or fender flare, plus the they have to be covered down to the centerline of the axle.