Study On Traffic Pollutant Emission And Fuel Consumption Based On Cellul Automaton Model

In recent years,the number of vehicles rapidly increases in major cities,harmful gases are emitted by vehicles to become an important cause of smog and respiratory diseases.The transportation industry consumes a lot of energy,and excessive energy consumption is restricting the development of the global economy.It is meaningful that to study traffic pollutants and fuel consumption.Traffic congestion not only affect road capacity but also lead to a large number of exhaust emissions and fuel consumption.There are many non-equilibrium and non-linear phenomena in the production of traffic congestion,which attract scientists to do a lot of research.Most traffic congestion are mainly caused by traffic bottlenecks,and there are traffic bottlenecks of different shapes and intensities in actual road traffic,such as ramp traffic,local road reduction,etc.Therefore,this paper study the pollutants emission and fuel consumption of road under different traffic types based on the cellular automaton model.The main research work of this paper is as following:1.Based on the Nasch model of mixed traffic flow,pollutant emission model of mixed traffic flow is proposed to study the emissions of particulate matter（PM）,CO₂,NO_xand volatile organic compounds（VOC）in mixed traffic flow under periodic boundary with different mixing ratios,different vehicle motion states,different maximum velocities and different vehicle lengths.The research shows that the pollutant emission of mixed traffic increases with the increase of mixing ratio.In the process of congestion formation,accelerating and decelerating vehicles have a great influence on the pollutant emission of mixed traffic flow,and decelerating vehicles emit the most pollutants.By introducing the distribution function of acceleration,deceleration and constant velocity,the emission of pollutants in different vehicle motion states is reasonably explained.When the mixing ratio and the length of vehicle are given,the larger the maximum velocity of the short vehicles,the more the emissions are,but the maximum velocity of long vehicles do not obvious effect.When the mixing ratio and the maximum velocity are given,the longer the vehicle,the less the emissions are due to the limitation of road capacity under the periodic boundary.2.Based on the three phase traffic flow KKW model,the fuel consumption and particulate emissions of single-lane traffic under open boundary are studied.The traffic phase diagram is obtained by numerical simulation,and the division of different regions of the phase diagram is related to the vehicle length.The traffic phase diagram region with 15 cells could be divided into free flow,congestion I phase,congestion II phase and maximum current（MC）.When the vehicle length is 5 cells,the phase diagram lacks MC.By analysing of the cross-correlation between local density-flow and the spatial–temporal patterns,synchronized flow（SF）on the area upstream of the road is determined.The fuel consumption and particulate emissions in different regions of the phase diagram are numerically simulated.It is concluded that the fuel consumption and particulate matter emission are the highest in the MC and congested I phase.The fuel consumption of synchronous flow is greater than that in the free flow,but lower fuel consumption than in the congested I phase and MC.3.Based on the cellular automaton Nasch model and the lane changing model,the particulate emissions model of the on-ramp traffic flow is proposed to study the particulate emissions of the on-ramp traffic under open boundary.The phase diagram of the traffic system is obtained by numerical simulation.The division of the phase diagram area is related to the length of the acceleration lane,the upstream of the main road and the on-ramp are in free flow;the upstream of the main road is in free flow and the on-ramp is in the congestion;the upstream of the main road is in the low velocity state and the on-ramp is in the free flow;the upstream of the main road is in the low velocity state and the on-ramp is in the congestion.The traffic flow and average velocity of each road section are obtained in different entry probabilities of the main road and on-ramp entry probabilities.The particulate emissions of each road section in the entry probabilities of different main roads and on-ramp entry probabilities are studied,the results show that when the upstream of the main road is in the low velocity state,the particulate emission is higher than in the free flow.The particulate matter emission is higher when the ramp is congested.As the on-ramp probability increased,the particulate matter emission on the on-ramp increased.