Say goodbye to the logjam of cars that snarl intersections during rush hour. New research from MIT’s SENSEable City Lab and the Swiss Federal Institute of Technology in Zurich shows how traffic light-free intersections and a connected network of sensor-laden, self-driving cars can reduce road congestion. The proposed system is so efficient that twice as many cars can drive on the road without any slow-down.
Using mathematical modeling, the researchers show how sensor-laden cars and traffic light-free intersections could reduce traffic congestion. In the scenario reviewed by the team, self-driving vehicles would travel autonomously on roads without traffic lights to control the flow of traffic. Instead of stop lights, cars would communicate wirelessly with other vehicles on the road, allowing them to travel at a safe distance without having to slow down for a traffic light.
This car-to-car communication would control the traffic flow so that cars can only enter an intersection when a slot is open for them to travel through safely. Cars would move slowly in small groups towards the intersection. As they reach the crossing, they then would slide through the intersection quickly. “You want the car to use the intersection for the shortest possible time,” says Paolo Santi, a member of the Italian National Research Council and researcher in the SENSEable City Lab.
In these slot-based intersections (SIs) Cars will move slower, but more efficiently since they don’t have to stop. This “slower is faster” form of traffic management is a well-known principle that already is being used to move crowds of people through building entrances, passageways, and other narrow areas. In the model published by SENSEable City Lab, the traffic-based system is so efficient that it could support twice as many cars without any impact on the rate of travel, claims the researchers.
While these slot-based intersections work in theory, they have limited application in the real world as cars often don’t encounter a single intersection. Cities, for example, have a network of concurrent intersections that need to operate in conjunction with each other. As part of their ongoing research, the team is exploring how this idea can be applied on a citywide level.