Why don't you try googling for Mexican traffic laws or whatever type laws you are concerned about. I always find if i'm stuck for info Google can usually help.
I concur - though you might need to know Spanish. Most nations (including Zimbabwe) have websites like our own that publish legislation and case law. The Canadian and U.S. sites are particularly good (and their uni lecturers are also very helpful). On that note, try emailing a few law lecturers at Mexican universities. Don't be too surprised to get a positive response. I got great help from a law lecturer at the University of Wisconsin.
If you are merely a traveller there is nothing different about Mexico that should trip you up, compared to travelling in any other developing country with a strong Catholic culture.
The area you are most likely to come into contact with is the traffic laws - just stick to the speed limits. One gets tickets on the basis of the traffic cops asserting you were going too fast - none of this cameras business.