Nah - you get citizens to self report odometer readings annually, or use annual inspections. And you employ a few people to run your 'fraud team' which will use CCTV to catch fraud, and auto-mail out letters with fines.

15 peoples civil service salaries = $1.5M say.

They will contact local car park owners, municipalities and states who have ANPR cameras, etc. From each, they'll get a spreadsheet of plate no, date/time and camera lat/lon. Many police departments already centralize that info to search for stolen cars etc.

They'll then run the whole lot through a python script to make a database of plate num + annual mileage. They'll then compare that to the self-reported mileage and investigate any underreporting.

Assume that this is implemented in the USA, and 1% of people fake the odometer by 50%. Assume the tax is 5 cents a mile. Total vehicle miles traveled is 3e12 miles, and assume we can easily detect 30% of offenders, due to them driving long distances on highways, and fine all those detected 3x the fraudulent amount. Total takings: $337M.

Clearly worth enforcing.