Interesting article from the Associated Press indicating that a new shortwave broadcast will provide US/Mexico border crossing information:
• Feds unveil system for speedier border crossings
"Shortwave" probably means a low-watt broadcast only intended for reception within several miles of the border, though.
Which travelers have vehicles equipped for receiving such signals? Truckers might already have the capability if the broadcasts are in the Citizen's Band (26965-27405 kHz). But the article describes the new system as if it's intended to help everyone who wants to cross the border.