Traffic congestion has become a vital enigma in most cities across the world. Longer trip times, air pollution, frustration in drivers, noise pollution, road accidents, delay in emergency services, etc. are some major problems people are facing as a result of traffic congestion. Old-fashioned traffic lights set up in cities are unable to meet the needs of advanced cities because these traffic lights have an exact predetermined time interval from a red phase to a green phase. Such systems do not take vehicular density into consideration. Several works based on sensors, image processing, IoT, RFID, etc. have been explored a great deal to automate the traffic lights according to the density of the vehicles on the road. The work presented here highlights the state of art of all the new and emerging methods of smart traffic management and the associated challenges. Overall, the paper reviews and summarizes the various methods of traffic management systems.

Keywords : Traffic Control; Image Processing; IR Sensor; Spontaneous Synchronization; VANET; IoT; Inductive loop.