OK, we can debate the merits of even basing auto insurance on local vehicular crime rates -- something the car owner cannot control -- another time, but what I want to know is how it possibly makes sense to use ZIP codes to determine this. A ZIP code is something determined by the postal service based on how they sort the mail.
My ZIP code is geographically pretty large, given that there aren't any major corporations receiving a high volume of mail within the ZIP code, so it's made up of a large number of residences and small businesses. It's also not a very dense neighborhood for an urban one -- no highrises or anything. So, my ZIP code includes a couple of areas fairly far from my home where there are vacant lots and abandoned vehicles. It also includes some rather large housing developments, where there is unfortunately a lot of petty crime. So, I don't doubt that I live in a ZIP code with a fairly high rate of vandalism to vehicles.
However, my particular precinct does not have a high rate of any sort of crime. My precinct -- which was determined by the city by grouping together properties with similar needs in terms of city services, not determined by the postal service according to efficient means of delivering mail -- is a leafy residential neighborhood of one, two, and three-family homes with small yards. I really don't worry about anyone damaging my car there. It would make much more sense for the insurance company to use my ward and precinct to determine the crime rate of where I actually park my car.
Another thing I wonder; how did they actually get statistics regarding crime rate by ZIP code? I can easily find the statistics by precinct, but I can't find a compilation by ZIP code. Do the insurance underwriters actually do some sort of sampling of ZIP codes found in police reports? Or did they just choose a precinct in the ZIP code at random? Or use the highest one?