Introduction - If you have any usage issues, please Google them yourself
design a crossroads for the traffic signal controller is a group in green, yellow and red lights to direct traffic. green, yellow and red, respectively for the duration of 20 seconds, five seconds and 25 seconds; When special circumstances (such as fire engines, ambulances and the like), in both directions were red light, stop time, when the special circumstances after the controller to restore the original state, continue normal operations