Study On Divergence Angle Of Direct Deceleration Lane Of Interchange

With the increase of highway mileage,the emergence of interchange greatly improves the traffic efficiency of cross roads.As an important part of the connection between the main line and the ramp,the direct deceleration lane is the area with high traffic accident rate.In recent years,many scholars have studied the length of the direct deceleration lane.China ’ s road specifications stipulate the length of the deceleration lane and the range of the divergence angle under different main line design speeds,but there is no specific analysis of the corresponding divergence angle range of different main line alignment.Based on this,this paper compares the provisions of domestic and foreign specifications on the divergence angle of direct deceleration lane,and takes the direct deceleration lane of single lane as the research object.On this basis,the divergence angle of direct deceleration lane is defined,and the range and applicability of the divergence angle of direct deceleration lane with different main line alignment are analyzed.Firstly,the driving behavior characteristics of the vehicle from the main line to the deceleration lane are summarized.Then,according to the actual investigation of the vehicle lane change on the direct deceleration lane,the lane change trajectory is analyzed and studied.The trajectory data are extracted by Tracker software,and the trajectory data are fitted by quintic polynomial and uniform cosine curve.Through the comparative analysis of the fitting curve fitting degree,the uniform cosine curve model with good fitting degree and simple calculation is finally determined as the actual lane change trajectory model of the direct deceleration lane,and the uniform cosine curve model that conforms to the actual driving characteristics is constructed.The fitting degree analysis and accuracy verification of the uniform cosine curve model and the actual lane change trajectory are carried out.The lane change trajectory of the vehicle under different main line design speeds is determined as the trajectory model of the simulation experiment.Then,the influencing factors of the divergence angle of the direct deceleration lane are analyzed.The vehicle dynamics Carsim and Trucksim simulation software are used to establish the road model of the direct deceleration lane with different mainline alignments.The lane changing trajectory model under different mainline alignments corresponding to the design speeds of 120km/h,100km/h,80km/h,80km/h and 60km/h under different mainline alignments.The lateral force coefficient and lateral acceleration change rate of the safety and comfort index are used to control the vehicle turning lane under different divergence angles,and the divergence angle range of the single lane direct deceleration lane under different mainline alignments,different superelevations and different design speeds is obtained.Finally,according to the simulation software,the standard flow angle and the maximum flow angle are simulated and compared.Lateral acceleration and tire load deviation rate are selected as vehicle handling stability index,trajectory tracking error is used as vehicle road tracking index,tire inclination angle and steering wheel angle are used as driver handling load index.The adaptability of vehicle driving stability and driver handling load is verified for the flow angle obtained by simulation.The applicability of simulation flow angle under special weather conditions such as wet or snow pavement is verified,and the reasonable maximum flow angle range of direct deceleration lane with different main line alignment is determined.The experimental results show that the divergence angle range of our country is relatively safe,and the divergence angle range obtained by the experiment is closer to that of the United States.The conclusion has certain guidance and practical significance for the theoretical design and engineering application of the divergence angle of the direct deceleration lane of the interchange.