[GreenLanternCorps]

Not possible, even if he wanted to, all highways are owned by the states, not the Federal government.

The states get money from the Congress to build and maintain them, but the states own them.

Route numbering does not effect ownership.

[MaxMax]

From Federal Highway Administration (FHWA)

The Federal Highway Administration supports State Transportation Agencies (STAs) by allowing
Local Public Agencies (LPAs), such as cities or counties, to administer Federal-aid projects.
The LPA program, as administered by the states, provides for construction,
reconstruction and improvement of highways and bridges on eligible
Federal-aid highway routes.

[TigersEye]

...all highways are owned by the states, not the Federal government.

That's what I thought.