"Bridge Ices Before Road" - those signs you see at nearly every bridge and overpass are there for a reason! Pavement on solid ground is exposed to cold air on only one side - but a bridge is exposed on all four sides, meaning it cools much faster than the road surface when temperatures drop.
This bridge is coated with ice from freezing rain, a phenomenon known as 'black ice'. An accident occured on this bridge just moments before this demonstration was filmed! Notice how invisible the ice looks - could you identify it if you didn't already know it was there? This illustrates how awareness of weather conditions and the potential for ice ahead of time is the best defense against getting into an accident.