Study On Traffic Fuel Consumption And Traffic Congestion Caused By Road Uphilland Downhill

People are faced with three major problems brought by traffic: traffic congestion caused by the increase of cars;Air pollution caused by vehicle exhaust emissions;The increase in the number of cars leads to increased energy consumption with the development of urban traffic.it is necessary to study the fuel consumption of automobiles on the roads and under different conditions.Therefore,the fuel consumption of traffic flow on uphill and downhill roads based on the micro optimal velocity model is investigated in this paper.The Na Sch(Nagel-Schreckenberg)model of mixed traffic is used in fuel consumption,and the traffic congestion problem on uphill and downhill is studied from the micro to macro models.The main study of this paper is as follows:(1)The microscopic traffic model on uphill and downhill is presented with consideration of the influence of speed difference between front and rear vehicles.The stability conditions are obtained by linear stability analysis,and the time-space evolution diagram of fuel consumption is obtained by numerical simulation.The simulation results show that the speed difference coefficient has a certain influence on the fuel consumption of traffic flow.The greater the relative speed sensitivity coefficient is,the more stable the fuel consumption fluctuation will be.The upslope angle has influence on the fuel consumption of traffic flow.The greater the slope,the greater the fuel consumption of traffic flow.The lower slope Angle has influence on the fuel consumption of traffic flow,the higher the slope,the smaller the fuel consumption of traffic flow.(2)Based on the Na Sch model of traffic flow,a cellular automaton model of mixed traffic flow is proposed.The average fuel consumption on single-lane under periodic boundary condition is studied by introducing the mixing ratio defined by the proportion of long cars.The numerical simulations result show that the fuel consumption per 100 km increases with the increase of vehicle occupancy.The fuel consumption of vehicles in different motion states is different.The fuel consumption of vehicles in accelerating state is the largest,followed by uniform speed and the least deceleration.The greater the mixing ratio,the greater the fuel consumption per 100 kilometers,and the longer the car length,the greater the fuel consumption per 100 kilometers.In the area with a low occupancy rate,the maximum speed is higher and the fuel consumption per 100 kilometers is higher.In the area with a high occupancy rate,the fuel consumption per 100 kilometers is the same because the vehicle space limits the vehicle to reach the maximum speed.(3)An extended macro hydrodynamic model is derived from a microscopic car-following model considering forward looking and backward looking effect on the uphill and downhill by employing the transformation relation from microscopic variables to macroscopic ones.The stability condition of this traffic model is obtained by performing linear stability analysis.Nonlinear analysis derives the Kd V equation and yields its solution to the density wave near the neutral stability line.We make use of the upwind finite difference scheme for simulation.The spatiotemporal evolution patterns of traffic flow on the uphill and downhill are obtained.When the road is uphill,unstable region is shrunken with slope of the gradient increasing and backward-traveling density waves gradually decrease and even disappear.When the road is downhill,unstable region is extended and density waves propagate quickly backward to the whole road with slope of the gradient increasing.