Research On The Alignment Quality Of The Long Downhill Section Of The Expressway Based On Operating Speed

With the rapid development of our country’s economy,the degree of western development is gradually deepening.Affected by the mountainous terrain,the continuous downhill will inevitably appear when growing up,which directly affects the safety of road traffic.Traffic accidents are likely to occur when the linear combination of long and continuous downhill sections is unfavorable,and the impact of linear combination quality on traffic safety is the focus of route research.Among the highways that are currently in the design stage and have been built or rebuilt,the proportion of long downhill sections is increasing day by day,and the traffic safety situation is getting more and more severe.Therefore,the quality of the long downhill linearity and the selection of linear indicators have an impact on traffic.The security impact is particularly obvious.Based on research at home and abroad,this paper analyzes the influencing factors of operating speed,vehicle speed and the relationship between traffic accidents,and combines actual accident data to analyze the accident distribution characteristics of long and large downhill sections,and summarizes the causes of accidents in long and large downhill sections.Features,to propose a method for correcting the running speed of the long and large downhill section.On this basis,combining the characteristics of linear balance and linear adaptability,comprehensively considering the characteristics of continuity,safety,and comfort of driving,selecting indicators based on operating speed(speed difference between adjacent sections,vertical and horizontal acceleration,unit The influencing factors of mileage relative speed difference and speed variation coefficient)are used as the evaluation target,and based on the method of maximizing the amount of information to determine the weight,a comprehensive evaluation method for the alignment adaptability of long and large downhill sections is constructed,and the balance of the horizontal and vertical alignment is evaluated..Finally,take a long and continuous downhill section of Qinglan Expressway as an example to verify the case.Combining the project’s reconstruction and expansion plan and the history of traffic accidents over the years,a suitable continuous long downhill section was selected as the research object,and the linear balance and linear adaptability of the long downhill section were analyzed.Sections with poor linear adaptability.Based on the calculation results of linear balance in this paper and the evaluation results of linear adaptability coefficients,it is possible to better identify long and large downhill sections with poor linear quality and road sections with poor running speed;combined with the evaluation results of the model,the balance Optimizing measures for road sections with poor adaptability can improve the driving safety of long downhill road sections to a certain extent..