If we ever adopt full autonomy and give total control over to our cars – or perhaps in a scenario where autonomy is required in certain urban zones – traffic lights will likely go the way of the internal combustion engine and the manual transmission (hey, this is the future we're talking about). Instead of stopping where traffic flows meet, the folks at MIT's Senseable City Lab foresee a system where vehicles communicate with each other to navigate intersections with "slots" that determine timing. The vehicles and infrastructure decide which cars enter the intersection at what time and speed in order to ensure smooth, safe, and efficient travel. As MIT explains, "Stop and go is largely avoided, which has the effect of reducing pollutants and greenhouse gases caused by acceleration and deceleration cycles." Check out the video above to see what that looks like.
Stop and go is largely avoided, which has the effect of reducing pollutants and greenhouse gases.
Intersections, and traffic in general, aren't so simple. Add in variables like pedestrians, cyclists, delivery drivers and, depending on the scenario, human driven cars complicate things. These intricacies are cause for some skepticism about the slot-based solution for the folks at CityLab. So, what then?
Here's where the big urban design changes come into play, as Lloyd Alter at Treehugger imagines traffic flowing on completely separate grades. Depending on the direction of traffic and the travel medium, various vehicles and pedestrians would travel along their own roads, separated by elevation. Think of the way vehicles travel around at different heights in Coruscant's skylanes in the Star Wars prequels, or in The Fifth Element. Of course, road- and pathways would need to be built as such to accommodate our gravity-limited vehicles, but it's the same idea.
Preferred modes of transport will influence the way cities look, and "drivers" of autonomous cars, as well as those who stand to profit from them, will have the loudest voice. This will mean limitations on where cyclists and pedestrians are allowed to travel. If Alter is correct, this will also lead to more urban sprawl, as well as grade-separated cities, where traffic flows are separated by elevation. As such, the cycle of humans creating things that in turn effect their own changes back upon their human makers will remain unbroken.
Of course, transportation could shape our cities in ways that haven't been discussed or even imagined. If you have your own ideas, you know where the comment section is.