They're also often far less confusing than people expect them to be. The interchange where you cross over is generally done at as close to a 90 degree angle as

They're also often far less confusing than people expect them to be. The interchange where you cross over is generally done at as close to a 90 degree angle as practical, so it "feels" like two one-way roads crossing at an intersection rather than switching to drive on the wrong side of the road.