Autonomous vehicles are going to radically change how we get around, and as they become commonplace in our streets, we'll need to rethink how we design our roadways.
MIT's Sensable City Lab looked at this problem a couple of years ago, producing an installation called DriveWave, which is responsible for the above video. Simply put, with autonomous vehicles, intersections and stop lights will need to change, because cars will have the ability to navigate through them effectively, without hitting other cars on the road. Removing the signals and allowing the autonomous vehicles to pass through on their own would in theory make everything faster.
A recent research article, published in the journal Plos One backed this idea up, proposing that 'Slot-based Intersections' will be more effective system that will be able to move cars through previously congested areas quickly.
The study, simulated a Slot-based Intersection, reasoning that safety would be the biggest priority, and suggests that this approach to traffic could essentially double the capacity that any given intersection could handle. This would not only cut down the amount of time spent in traffic, it could also cut down on emissions by cars that are idling for long periods of time while waiting to get through.
The downside to this is that you really need to have a high number of autonomous vehicles on the road for this to work: human drivers would mess up the planning and render the entire thing useless, or cause accidents. And, with a lot of established infrastructure to change over, this isn't an overnight process. But, it is a good first step towards figuring out how to go about changing our roads when our cars can drive themselves.