Road safety and traffic congestions are among major concerns today. The Global status report on road safety 2013 indicates a worldwide total number of road traffic deaths of 1.24 million per year. A large part of them occurs at intersections. Intersection management is also critical to reduce the traffic jams in our cities. However, the percentage of intersections that are governed by traffic lights is inevitably limited and significantly increasing the number of traffic lights is not realistic due to the heavy costs of deployment and maintenance. Besides this, traffic lights generally work under fixed or slowly varying time settings, thus inefficiencies are likely to occur.
Today's wireless communication technologies allow to implement a radically new approach to this issue: through accurate positioning systems and short range wireless communications, vehicles could communicate their own position to each other and they could autonomously coordinate the intersection management in a safe and efficient way. A Virtual Traffic Light (VTL) could then be shown to drivers to control who should stop and who goes next.
Supported by the European EIC ICT Labs, in the "Next generation car-to-X" activity, the Istituto di Elettronica ed Ingegneria dell'Informazione e delle Telecomunicazioni (IEIIT) designed, implemented, and tested a Virtual Traffic Light algorithm for intersection management.
Dedicated hardware and software have been installed inside each vehicle, running the VTL algorithm. Communication has been provided through a new standard belonging to the Wi-Fi family, denoted IEEE 802.11p and operating at 5.9 GHz. Thanks to this technology and a GPS, each vehicle communicates its own position in real time and receives the position of the other vehicles approaching the same intersection; inside each vehicle, the algorithm runs and defines the priorities. Then, a direct communication among vehicles is performed to agree upon the algorithm result, and a green or red virtual traffic light is shown to the driver.
In addition to tests conducted in our laboratories adopting virtual coordinates, we validated the application in a real field trial.
Besides improving intersection management where traffic lights are not deployed, this technology can be applied to control fleets of autonomous vehicles in closed areas, such as airports. Furthermore, it is also an important step towards intersection management for the next generation transportation systems, where vehicles will be driverless.
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