Based on NaSch model, energy consumption in the mixed traffic flow was investigated. The formula of energy consumption was presented. There are three factors of mixed traffic flow to be studied, which are the maximum velocity, length of vehicle, and the ratio of the mixed traffic flow （Cn）, respectively. Simulation and analysis indicated that the energy consumption of the mixed traffic flow consisting of vehicles of the same length but different maximum velocity is associated with the lowest maximum velocity and its ratio. The slower the maximum velocity and its fraction, the more energy consumed. Moreover, for the mixed traffic flow consisting of vehicles with the same maximum velocity bot different length, the energy consumption is related to the ratio Cn of mixed vehicles. Longer vehicles lead to more energy consumption. For the mixed traffic flow involing vehicles of different maximum velocity and lengths, its energy consumption is determined by the ratio Cn of the mixed vehicles and delay probability p, the more the short and fast vehicles（Cn→0）, the less energy consumed, and vice versa.

Based on the Fukui-Ishibashi model (FI model), the energy consumption in the mixed traffic flow is investigated via considering three factors: maximum velocity, length of vehicle, and the ratio of the mixed traffic flow. Simulations and analyses indicate that the energy consumption of the mixed traffic flow with the same length and different maximum velocities is related to the slow maximum velocity and its ratio. The slower the maximum velocity and its ratiare, the more energy will be consumed. Moreover, for the mixed traffic flow with the same maximum velocity and different lengths of vehicle, the energy consumption is related to the ratio of mixed vehicles. Longer vehicles induce more energy consumption. For a mixed traffic flow with the different maximum velocities and lengths of vehicle, its energy consumption is determined by the ratio of the mixed vehicles and delay probability p. The energy consumption of FI model drops off suddenly and trends to zero at the maximum flow rate, where there exits a maximum peak, which is significantly different from the result from the NaSch model.

Based on the cellular automaton traffic flow model of automatic cruise controlling, the influences of speed maximum, mixing ratio, expectation factor of speed, and mass of vehicle on energy dissipations of the mixed traffic system are studied. Through computer simulation, the energy dissipations of mixed traffic system under the different parameters are obtained and analysed by the mean field theory. The theoretical analyses are consistent with the results of numerical simulation.