Where can I find police requirements, if any, for “pacing” or “clocking” a vehicle in California?
Speaking as a former prosecutor, there aren’t any “police requirements” for pacing or clocking. It’s basic physics – the officer looks at his speedometer once he’s matched velocity with your car. You can try and assert that the officer didn’t have enough time to clock you, but using common sense, it doesn’t take that long. But it will basically boil down to your word against the officer’s. Are you sure he didn’t use a radar gun? If you really want to get out of the ticket, or reduce it, I recommend getting a recommendation for a defense attorney who specializes in traffic tickets.