 As you enter the interchange, the right and left sides of the road cross over, each other at a stoplight. You are, in fact, driving on the left side of the road at this point. From there, left turns become a lot easier because there's no oncoming traffic in the way. Instead of waiting for a signal, you get a free left turn. There are now more than 200 of these double diverging diamond interchanges in the United States in 30 states.