Research On The Setting Of The Three-lane Off-ramp Diversion Area Of Expressway Interchange

Interchanges are important nodes in the expressway system.By connecting expressways in different directions,the purpose of traffic conversion is achieved.With the rapid economic development,and the sustained growth of vehicles population,it results in an increase in traffic flow.In order to meet the increasing traffic requirements for inhabitant trip,the off-ramp D of Wanqingsha Interchange was designed as a three-lane in the design scheme of the deep and middle corridor.However,codes do not provide regulations for the setting details of three-lane ramp for expressway interchanges.Based on the "Road Route Design Code" and "Interchange Design Regulations",this paper focuses on the location setting of off-ramp guide signs and the length of deceleration lanes with analyzing traffic characteristics in the off-ramp of expressway interchange.For the study of the location setting of the three-lane off-ramp guide signs of expressway interchange.Based on the two-way eight-lane expressway and the direct three-lane off-ramp,The model drivers driving out off-ramp is constructed,and the location of the three lane off-ramp guide sign is calculated with taking the diversion nose as the ramp control point.For the research on the length setting of the deceleration lane at the three-lane off-ramp of the expressway interchange,combined with the measured data of the Xi’an Raocheng Expressway and the linear design parameters of the Wanqingsha Interchange,this paper calculates the deceleration lane length of two-lane + three-lane off-ramp and three lane off-ramp in the medium and long term plan of Wanqingsha interchange based on the secondary deceleration model and a three-lane off-ramp deceleration lane length setting scheme was proposed.Finally,combined with examples,the VISSIM microscopic traffic simulation software was used to verify the advantages and disadvantages of different setting schemes by simulating the three-lane off-ramp guide sign location setting scheme and two different deceleration lane length setting schemes.It provides reference and theoretical basis for the compilation and revision of "Highway Intersection Design Code".