Characteristics Of Highway Traffic Flow Mixed With Electric Vehicles And Fuel Vehicles

As electric vehicle technology continues to advance,the joint promotion of the world’s countries,electric vehicles are entering a high-speed development stage,and the future highway system will be in a long-term situation of mixed fuel and electric vehicle traffic.The impact of electric vehicle participation on the capacity,congestion,safety,and stability of mixed traffic flows deserves further investigation.Both the driver and the vehicle are the core of the traffic system.The influence of the driver’s driving behavior and the vehicle’s motion characteristics on the traffic flow will directly affect the overall running state of road traffic.Therefore,it is of great practical significance to research the electric-fuel vehicle hybrid traffic flow based on considering the driver’s characteristics.In this paper,we establish a mixed traffic flow model based on vehicle motion characteristics and driver characteristics and study the influence of considering vehicle motion characteristics and driver characteristics on mixed traffic flow characteristics through the basic diagram,stability index,and safety index.The main research work is as follows:(1)Firstly,Analyzing the motion characteristics of a vehicle based on its structure and the motion curves of vehicles in established studies,and using acceleration to distinguish between the differences in the motion of the two vehicles,Introducing Gipps’ theory of following to characterize the changing safety distances in motion,thus classifying the acceleration,deceleration,and uniformity processes of the vehicle,According to the driver’s pursuit of desired speed,front and rear vehicle speed difference,choose different degrees of acceleration and deceleration amplitude,and introduce auxiliary variables to improve the simulation accuracy of the model,improve the NS model,establish a mixed traffic flow model considering the degree of vehicle acceleration and deceleration,and use Matlab software for simulation and numerical statistics.The results show that: electric vehicles can improve the road capacity,the travel speed of the traffic flow,and the safety of the traffic flow near the critical density,and can alleviate the congestion of the traffic flow near the critical density,and the TIT curve is found to identify the state change of the traffic;in the case of high density,the mixing of electric vehicles will make the speed of fuel vehicles fluctuate more and drive the speed of the overall traffic flow to show a rising trend,and the safety of the homogeneous traffic flow is low,and the addition of electric vehicles in the mixed flow produces a greater disturbance to the speed of the traffic flow and the safety is reduced.(2)Secondly,One of the cores of the road traffic system is the driver,whose driving behavior affects the overall operational status of the traffic.In this paper,drivers are classified as aggressive,smooth,and conservative according to their driving styles.Drivers with different driving styles will have different safety spacing due to different braking reaction times,and there are changing random driving behaviors under changing motion scenarios.Therefore,considering the specific motion process of the vehicle and the driver’s behavior,a hybrid electric-fuel vehicle traffic flow model considering the driver’s characteristics is established and subsequently analyzed by numerical simulation with Matlab software.The results show that the simulation effect of the improved model is close to reality and can reproduce the rich traffic phenomena such as sub-stability;from the analysis of the flow density relationship diagram,we can get that the combination of the aggressive driver or smooth driver and electric vehicle in the traffic flow can improve the road capacity,and the combination of conservative driver and electric vehicle reduces the capacity when the proportion is small,and increases the road capacity when the proportion is large;from the threshold of congestion occurrence The combination of aggressive drivers or smooth drivers and electric vehicles can effectively reduce congestion,but the combination of conservative drivers and electric vehicles can effectively reduce congestion when the proportion is high.When the proportion is large,safety will be reduced,but the combination of a conservative driver and an electric car can effectively improve safety.(3)Finally,By studying the lane change behavior of mixed traffic flow,the deficiencies of the STCA model are analyzed,and on this basis,the driver’s lateral driving characteristics,and vehicle motion characteristics are considered,and random utility theory is introduced in the lane change process,to establish a mixed traffic flow model in a two-lane environment,and simulations and statistical analysis of data are performed.The results show that the improved model can make up for the shortcomings of the classical model STCA model;the vehicles on the two-lane road will show a relatively balanced state after running for some time;the lane change of vehicles is not only influenced by the choice of drivers’ tendency,such as conservative drivers’ lane change conditions are more severe and less likely to change lanes,but also influenced by the degree of traffic relaxation,especially in the lane change process of aggressive and smooth drivers.In homogeneous traffic flow,EVs change lanes more frequently than fuel cars,and a small amount of EVs mixed in heterogeneous traffic flow can increase the lane change frequency of traffic flow,while a larger proportion of EVs will reduce the lane change frequency of traffic flow;as the combination of aggressive and smooth drivers and EVs increases,the lane change frequency tends to decrease and then increase,and the combination of conservative drivers and EVs will reduce the lane change frequency of traffic flow.The combination of conservative drivers and EVs will reduce the lane change frequency.