This bill amends title 23, United States Code, to direct the Secretary of Transportation to withhold a portion of federal highway funds from states that do not address certain roadway obstructions. It mandates that 10 percent of specific federal apportionments will be withheld from states failing to make reasonable efforts to prohibit dangerous activities on Federal-aid highways. The core requirement is for states to prevent individuals, not performing government work, from knowingly and recklessly obstructing lawful vehicle transportation in a manner that endangers public safety or health. This measure aims to ensure clear and safe passage on major roadways. The withholding of funds will begin on the first October 1 after the Secretary issues necessary regulations or after a state's legislative session, whichever occurs later. The Secretary is also tasked with issuing these implementing regulations within 180 days of the bill's enactment to facilitate its implementation.