This article demonstrates that the federal government does not (and should not) have the power to act in this manner. CNN found a single law professor who stated this:
> "I don't think that the statute can be read broadly enough to apply to all people merely moving on an interstate highway," Blackman said. "Once you go beyond people in federal facilities, you're really intruding on what the state's responsible for."
At best, they can cover Federal buildings with a policy. That is it.
Your comment proves the article's point. In the entire country, they could only find a single professor to say that the federal government doesn't have the power to issue a mask-mandate for occupants of vehicles on interstate highways.
Given that these roadways in question are interstate the federal government's power to regulate activity thereon is assumed as the power to regulate interstate commerce is one of the constitutionally enumerated powers of the federal government.
> "I don't think that the statute can be read broadly enough to apply to all people merely moving on an interstate highway," Blackman said. "Once you go beyond people in federal facilities, you're really intruding on what the state's responsible for."
At best, they can cover Federal buildings with a policy. That is it.