Normally in traffic control, there will be a traffic police who controls the green, red and yellow signals according to the vehicle traffic. If there is no traffic police, some traffic junction will have only have timer enabled signals which will not be effective in traffic signal controls.
Here, we can use the Zigbee wireless sensors in the traffic sides, which will sense the traffic density and can be sent the detected signals to a central controller.
The sensed traffic density can be analysed using a microcontroller or FPGA kit, so that according the density in each of directions, the control signals can be generated. In this way we can generate accurate control signals for green, red and Orange (yellow).
This type of control can also be used to control the signals during emergency or VIP vehiles passing on the signal junctions.
Some of the other features of Zigbee controller(as switch)
A ZigBee Relay Controller is a device that is capable of wireless remote contact closure switching. ZigBee offers wireless serial communications, making it possible to remotely operate a switch using very short serial commands. A ZigBee Modem is required for wireless computer controlled switching. A ZigBee Modem plugs into the USB port of your computer and emulates a Com Port (also known as a virtual COM port). Your software simply opens the serial port and sends a few bytes of data. The ZigBee Modem handles all wireless communications to and from the remote device.