The task aims at building a multi-level control of the traffic in large urban transportation nets. The basic unit we operate with is the traffic microregion. It is a logically delimited collection of crossroads and the communications joining the crossroads. We suppose, some of the crossroads are controlled by signal lights and the arms of the controlled crossroads are equipped by detectors -- measuring devices, providing us with transportation data (intensities and densities of the traffic flow).
The basic variable we model and control is a vector of queue lengths that are being formed in the arms of the controlled intersection. The queues are approximated by the number of vehicles, using the physical principle "the increment of the queue is given by the difference in the amount of incoming and outgoing cars". In addition to this, a linear dependence of the car density measured on the remote detector on the column length is considered. In this way a state space model for queue lengths and density in the microregion is constructed.
The controller built on the basic of the presented model has three levels:
The traffic control algorithm based on these principles has been developed in cooperation with ELTODO EG and finalised and practically tested in cooperation with ELTODO dopravní systémy.
Currently we are in the process of extending the model and improving the controller in the scope of a project NOMŘÍZ, a joint effort of ÚTIA, ELTODO dopravní systémy and Czech Technical University, Faculty of Transportation Sciences.
Contact:
http://mys.utia.cas.cz:1800/svn/doprava