Why do bridges freeze before the road surface?

The air temperature feels the same if you're standing on the road or the bridge. Bridges do indeed freeze before roads, and there's a good reason why. It all has to do with science! As the air temperature decreases, the surface of both roads and bridges will begin to cool down. read more

Even while the temperature on the road surface is dropping, the heat underneath the road keeps it warm enough to prevent icing as temperatures in the atmosphere drop below freezing. Bridges have no way to trap any heat, so they will continually lose heat and freeze shortly after temperatures in the atmosphere hit the freezing point. read more

The bridge is kind of like the surface sand, only it is suspended in the air all around. The bridge doesn't have that insulation. Air temperatures change rapidly. read more

Bridges do indeed freeze before roads, and there's a good reason why. It all has to do with science! As the air temperature decreases, the surface of both roads and bridges will begin to cool down. read more