A wintry mix threatens to create slick conditions for Monday evening's commute. The electronic message boards along Interstate 64 warn drivers heading up Afton Mountain to beware of black ice. The Virginia Department of Transportation did not pre-treat the interstates because crews predicted that the rain would wash it off. VDOT says crews are on standby to start putting down a salt and abrasive mixture to prevent an icy build-up.

Based on the paragraph above can we conclude that "the message boards warns of black ice"?
Yes