CRONOS

CRONOS Software

Real-time traffic signal control for urban intersections

Contact: Florence Boillot.

CRONOS software is a real-time traffic signal control system for urban intersections.

Every second, Cronos determines the optimal traffic light signal for the regulated area using a constrained optimization algorithm that minimizes the total waiting time for vehicles in the area.

CRONOS is one of the few systems designed to fully leverage detailed spatial traffic data derived from image processing using video sensors: queue lengths, spatial occupancy rates, in addition to standard traffic flow rates. This data provides the system with a wealth of information on the actual traffic situation.

CRONOS also regulates surface public transit (buses) by integrating them with the goal of overall traffic flow. In this context, it can prioritize or, conversely, delay a bus depending on how far ahead or behind schedule it is. It also allows certain buses to be given absolute priority if their delay exceeds a set threshold.
Two experiments were conducted to evaluate its performance:

At an intersection in Arcueil: CRONOS reduced the average waiting time per vehicle at the intersection by approximately 20%. It also reduced the average number of stops by about 11% and the percentage of vehicles making at least one stop to cross the intersection by approximately 8%. CRONOS reduced CO2 emissions and fuel consumption by 14%, excluding the unavoidable portion of CO2 emitted when crossing the intersection without slowing down (accounting for 70% of total CO2 emissions).

- At five intersections in Versailles: Regarding overall traffic management, CRONOS reduced average wait times by approximately 13% across the entire area during peak traffic hours and by 10% during periods of light traffic.

For further information :

F. Boillot, P. Vinant, J.-C. Pierrelée, « On-field experiment of the traffic-responsive co-ordinated control strategy CRONOS-2 for under- and over-saturated traffic », Transportation Research Part A, 124 (2019) 189–202.

F. Boillot, J.-C. Pierrelée, P. Vinant (2015), « Commande des feux CRONOS, sa méthode et son évaluation à Versailles », Livrable IFSTTAR du Contrat d’Objectifs et de Performances 2013 – 2016 entre l’Etat et l’IFSTTAR.

F. Boillot, S. Midenet, J.C. Pierrelée, « The real-time urban traffic control system CRONOS: algorithm and experiments”, Transportation Research Part C, vol 14, issue 1, february 2006.

S. Midenet, F. Boillot, J.C. Pierrelée, “Signalized intersection with real-time adaptive control: on-field assessment of CO2 and pollutant emission reduction”, Transportation Research D, n°9, Janvier 2004, 29-47.