This will be used as a special sign to indicate to drivers that autonomous vehicles are controlling the road at that moment. Today, traffic lights tell us when to stop or go on, but autonomous cars can communicate among themselves and with these traffic lights to organize the traffic flow in a faster and more precise way than humans.
in other words corporate interests cant develop a tech that works reliably so they take over a public chattel to change the standard for everyone so they can operate a weak tech development.