Analytical studies of CO2 emission in a mixed traffic flow with different vehicles

In this paper, we investigate the CO2 emission in a traffic flow mixed with multi-class vehicles by use of an improved optimal velocity model with different vehicles. We explore numerically the dependence of the total CO2 emission rate and the additional CO2 emission on the variation of the maximum velocities among vehicles for the free traffic flow, the co-existing traffic flow and the congested traffic flow respectively. We also simulate the effects of the average value of the maximal velocities of all vehicles on the total CO2 emission rate and the total additional CO2 emission rate for three traffic flow regions. The detailed analyses are conducted to explain the numerical results, and some practical suggestions to reduce the carbon emission are proposed for the real traffic.