If they used bridges instead of intersections where the roads cross over each other there would be no need for traffic lights and it would further reduce the ch

If they used bridges instead of intersections where the roads cross over each other there would be no need for traffic lights and it would further reduce the chance of someone driving into oncoming traffic. The bridges could run on top of each other and further reduce the area needed for the interchange. I'm sure bridges are more expensive than roads but it seems the obvious choice versus stopping four lanes of traffic at a light.