Study On The Impact Of Freeway Interchange Sections On Driving Workload

Interchanges are important nodes of expressways.Improving the safety of interchange sections is of great significance to improving the traffic safety and transportation efficiency of the entire expressway network.Scholars have always focused on the research on the influence of road alignment,traffic flow and other factors on the workload of drivers,but how the type of interchange and its components affect driver workload needs to be further explored.In order to solve this problem,this paper adopts the method of field driving test combined with questionnaire survey to study the influence characteristics of the ramp form of interchange and the general interchange on the subjective and objective workload of the driver,and determines the variation of drivers’ workloads at different interchange sections.The influence of road traffic safety facilities on the visual characteristics of drivers is explored,and the information threshold of the guide signs of interchange sections is proposed,in order to provide a theoretical reference for the design of interchanges and traffic safety facilities.This article introduces the research on the definition,theoretical basis,measurement methods and calculation models of workload in different fields.Based on the analysis of the factors affecting the workload of the driver,the connotation and characterization indicators of the workload of the driver are further clarified,which lays a foundation for the follow-up research.In order to obtain driver workload evaluation index data,25 drivers were openly recruited from the society,five interchanges in Shaanxi Province were used as the research objects.Field experiments were conducted to obtain drivers’ driving behavior and electrocardiograms during the driving of the interchange section,vision and other data,and collect the driver’s NASA-TLX scale score.Focus on the analysis of the changes in the five indicators of the driver’s heart rate growth rate,RMSSD,pupil diameter growth rate,gaze duration,and vehicle speed during driving on the interchange section.Established a driver workload model that combines the average score of NASATLX scale(subjective index)and the standard deviation of heart rate growth rate(objective index),which provides a basis for the evaluation of the workload of drivers on interchanges.Combining with the performance of the driver’s task,the influence of different interchange types and ramp forms on the driver’s workload is explored.Based on the research results of relevant sign information at home and abroad,a guide sign information calculation rule based on the characteristics of the information unit is proposed.Analyzed the impact of road traffic safety facilities on the driver’s visual characteristics during the driver’s driving on an overpass,and found that the gaze duration,pupil diameter growth rate and the amount of sign information have a significant positive correlation.On the basis of further analysis of the influence of the sign information on the driver’s gaze duration and pupil diameter growth rate,the information threshold(7 information units)of the road sign of the expressway interchange section was obtained.The research results of this paper can provide a theoretical reference for the design and operation management of expressway interchanges and traffic safety facilities,and are of great significance to ensure the driving safety of the interchange sections.