Let me try this comment again.

There is no driving with privacy or anonymity unless you’re on private land.

Anyone got tips for how to anonymize their car?

Remove the license plate. You will rarely have privacy driving a car on a public road. You should disable the modem, of course, but you’re still not going to be driving anonymously or privately. Automated license plate readers means your travels are going into databases that very well could be breached at some point in time.

Law enforcement use of ALPRs is rapidly expanding, with tens of thousands of readers in use throughout the United States; one survey indicates that in 2016 and 2017 alone, 173 law enforcement agencies collectively scanned 2.5 billion license plates.

According to the latest available numbers from the Department of Justice’s Bureau of Justice Statistics, 93 percent of police departments in cities with populations of 1 million or more use their own ALPR systems, some of which can scan nearly 2,000 license plates per minute. In cities with populations of 100,000 or more, 75 percent of police departments use ALPR systems.

Despite this expansive data collection effort, many departments have not developed a policy to govern the use of ALPR technology, or provided privacy protections.

https://www.brennancenter.org/our-work/research-reports/automatic-license-plate-readers-legal-status-and-policy-recommendations