Global warming is a very serious problem which is becoming ever worse as the growth in the number of vehicles. This paper presents a real time traffic lights control scheme for reducing vehicles CO2 emissions based on the Electronic Toll Collection (ETC) installed vehicles. Real time road conditions are obtained by wireless communication between the vehicles and the traffic lights based on the Dedicated Short Range Communication (DSRC) technology. A decision tree classification algorithm is used to calculate optimal average waiting time, then to calculate the CO2 reductions. Compared with fixed-time control, simulation results indicate that more than 26.9% idling time CO2 emissions can be reduced when traffic flow is heavy, meanwhile vehicles have a 0.07 higher probability to pass the intersection by non-stop when traffic flow is light.