Same as with breathalyzers. They'll start off with ones registered to the offender because otherwise the law wouldn't pass. Then, 5yr later, at the behest of

Same as with breathalyzers. They'll start off with ones registered to the offender because otherwise the law wouldn't pass. Then, 5yr later, at the behest of the interests running the breathalyzer/speed limiter company, they change the law to be "all cars at this address".