I've thought a fair bit about speedtrap registries, with my own history of getting speeding tickets, and I'm convinced they're useless. What's to stop the cops from adding a ton of false positives to the database? Even if the data is good, it's still worthless.

Real world example: I can detail for you all the places on I-10, near my house, where I've seen radar or laser speed traps. If you add them all together, it says you just can't speed there at all. I-10, for a few miles anyway, is five lanes wide in each direction, so traffic naturally speeds up there, and that's where the cops hang out. Given that warning, would you drive (a) the 60mph posted speed limit, (b) the 75-80mph flow of traffic, or (c) the 90mph that you can do quite safely when it's not rush hour?

What we really need is real-time surveillance of speed traps. I was driving in Munich, and my passenger (a native German) was translating the radio for me. After the usual weather and traffic reports, they were happily saying where the photo radar traps were located that day. Give me that, and I'll tune to your radio station in a flash. Even better, let's get satellite surveillance. Why should the Feds have all the fun to themselves? Modern high-resolution satellites should be good enough to identify the locations of police cars. I'll pay $10/month for them to beam that data to an in-car GPS navigation system.