An overpass is a bridge that carries one road over another road, allowing traffic to flow on two different levels without stopping. When you're driving on a highway and see a bridge crossing above you, that's an overpass. When you drive up and over that same bridge, you're using the overpass to cross the highway below.

Overpasses solve a tricky problem: how to let two busy roads cross paths without creating a dangerous intersection where cars have to stop and wait. Instead of traffic lights and turn lanes, an overpass lets both roads keep moving. One road goes up and over, and the other continues straight underneath.

Cities use overpasses to connect neighborhoods separated by highways, and they're common on interstate highways where stopping can be dangerous at high speeds. Some overpasses include pedestrian walkways so people can safely cross busy roads on foot. The overpass might seem simple, but it's a clever piece of engineering that helps modern transportation work smoothly. The opposite of an overpass is an underpass, which is the view from below: the tunnel-like space where one road passes beneath another.