Simply because you do not own the roads, you do not clean up the mess and you don't have to pay for all the costs of hospitalisation, rehabilitation and permanent disability. It's called vehicle registrations and drivers licence, don't like it, walk or take public transport.
Neither does the federal government. Roads are owned by state and local governments. The clean up is usually done by the local government. The insurance that I pay for pays for the expenses that result, and if I'm at fault, both my insurance company and myself are liable for damages.
Motor vehicle transportation, including licensing and registration, has always been a state issue - so why is it acceptable for a group of unelected federal bureaucrats to pass a decree that would greatly implicate the privacy for the majority of the population? Where do they derive their authority? Do you think something like this would actually go anywhere if they tried to enact it by legislation?
Furthermore, is there a real problem that this solves, or is it just a solution in search of a problem? Will this really provide that much more useful data that can't be determined through traditional means (aka measurements and physics)? I just see this being too susceptible to abuse - ie police scanning impounded cars as part of their 'inventory inspection' and writing additional summons for what they find.
For large values of one, one equals two, for small values of two.