New “slot” systems may soon eliminate the need for traffic lights at intersections
Traffic lights were first developed over 150 years ago to regulate rail traffic in London. They are a vestige of the past that lingers on in our digital era. Today, as telematics innovation and development make our motor vehicles and roads constantly securer and safer for everyone, the objective of developing self-driving cars and smart cities looms ever closer on the horizon.
A joint research project developed by the Massachusetts Institute of Technology (MIT), the Italian National Research Council Institute for Computer Science and Telematics (CNR-IIT) and the Swiss Institute of Technology (ETH) is in the process of perfecting a “slot” traffic management system similar to that of airplane traffic control in the vicinity of airports. The system, which produces a “just on time” flow of traffic, eliminates queues and delays, thereby also reducing petrol consumption and gas emissions.
The slot-based system univocally identifies vehicles and assigns a custom schedule to each one, a personal time slot during which the vehicle is scheduled to pass through an intersection, eliminating the need for vehicles to stop at traffic lights. The speed of each vehicle is automatically controlled so that it will pass through the intersection during the assigned slot, just as airplanes do in an airport. And the beauty of all this is that the system employs technology and communication systems that are already present in many modern cars.
“The transition from traffic lights to this innovative system will significantly improve the efficiency of intersections,” explains Paolo Santi, a CNR-IIT researcher and member of the MIT Senseable City Lab. “Our analyses reveal that with the present traffic flow rates, queues disappear entirely and delays are nearly eliminated.”
Slot system intersections are similar to smart roundabouts that vehicles engage by slowing down without ever stopping and having to start again. The results of the tests indicate that the slot-system doubles the number of vehicles that can be managed without creating queues, compared to traditional traffic-light intersections.
Carlo Ratti, MIT Senseable City Lab Director, confirms, “ICT technology and self-driving cars will transform the panorama of urban mobility. In the relatively near future, when all vehicles drive autonomously, we can imagine a scenario in which vehicles will never need to stop, moving continuously without risking collisions.”
The results of the study, conducted in collaboration with the Fondazione Centro Studi ENEL, have been published on the PloS ONE scientific journal.
For further information:
- Revisiting Street Intersections using Slot-Based Systems (PloS ONE, 2016)