You need a license to legally use the US highway system. It is patrolled by police who can stop you at any time and request your documents. You can have that license revoked for a variety of reasons.

The highway has a crapton of regulations around how you can use it. Speed limits, rules against drunk driving, driving only in 1 direction, requiring your lights be on (in some places during the daytime).

Nobody (almost) complains about limits on "free driving."