Get your technician ham radio license + APRS (www.aprs.fi) tracking gear and a dashcam, and you can transmit the images/data/voice to an off-site FTP server in case the cops "accidentally" destroy/lose your hard/drive or SIM card during a "cursory search of your vehicle".
If a cop is willing to lie to get you in trouble, he/she is willing to destroy evidence that will exonerate you.
Most likely the dashcam would be out of sight after impact unless they're hard_installed. I was making safe left after holding at a busy intersection waited til light turned red, the middle eastern driver (he might be in the phone or reading his text not paying attentionn to his driving) drove on me. My GPS and dash cam disappeared from the dash board, a bystander came to me who saw the whole accident. Just in case, it will be too easy to just eject the microSD or SD if other driver is LEO he'd want to confiscate your dashboard cam.