What I use down here in D.F. wouldn't apply, but wanted to add some information on insurance and situations down here and foreigners.

From my experience, the foreigners who I have known get into accidents deal only with the insurance companies, not the police here in the metro area. An accident occurs and both people call up there insurance company and they come out to the scene and it's settled there. Only if one of the people doesn't have insurance is there a problem. I have known that police will sometimes stop by a scene, but once they see both parties have insurance, they move on. They most certainly do have it down to a science.