Abstract: Traffic signals are the most convenient method of controlling traffic in a busy junction. Present traffic signals fail to control the traffic effectively when a particular lane has got more traffic than the other lanes. PLC or Programmable logic controller was used to control a mechatronics system using specific functions. The intelligent or “Smart Traffic Control” is one which would be able to calculate the vehicle density in a lane at a 4-way crossing and then decide the priority automatically using a program. In PLC the status of the sensors are checked and certain logical operations are performed to decide which lane is to be serviced first and provides output signal to the traffic lights poles for ON or OFF the Red, yellow or Green lights and ON time is depend on the specific priorities.

Keywords: Traffic control, PLC vehicle density, smart traffic control.