Research On The Reasonable Allocation Of The Number Of Entrance And Exit Lanes Of Intercity Interchange

The Intercity Interchange is the "big artery" node of the metropolitan area transportation,which can meet the planning and design requirements of modern urban traffic with high speed and large flow.The speed of urban traffic flow and the number of road lanes in the "in-city-out-city-transit traffic" highway network.The reasonable configuration can improve the overall transportation efficiency of the vehicle.As an important traffic node in the intercity rapid transit system,the round-the-city interchanges control all or part of expressways,urban ring roads,and the change of driving directions,which is the key to restrict the development of urban expressways.The most important feature of the three-dimensional intersection node in the city is: it can meet the four major traffic flows("out-of-city" traffic flow,"into the city" traffic flow,"in-city" travel traffic flow,"cross-city" traffic flow).It is required that traffic flows in all directions can be smoothly distributed to all areas in the "center" of the city.Through the review of related materials,the driving conditions and traffic characteristics of the junctions and junctions of the interchanges around the city are analyzed,and the three elements of traffic flow are proposed: speed,density,flow,and the driving state of the traffic flow is described and summarized.5 traffic flow models.On this basis,it analyzes the interference factors of roundabout interchanges and junctions,and specifically analyzes the four aspects of road factors,traffic conditions,traffic facilities,and environmental factors.Next,the capacity of the interchange and junction areas in the round-the-city interchange is analyzed.According to the combined form and characteristics of the interchange and junction,the ramp is connected to the main line into four simple import and export combinations,and then the road sections of different combinations are divided.Carrying capacity calculation for three computing units(merging area,diverging area,interweaving area).Firstly,through the VISSIM simulation,a lane number matching study based on the confluence model was established.The impact of the ramp 1 lane and ramp 2lanes respectively entering the main line on the capacity and service level of the simulated road system was analyzed.The average cross-section speed and travel delay time were analyzed and given.The recommended values for the reasonable configuration of the number of lanes on the main line are included.Then,a lane number matching study based on continuous confluence model is established.By setting different continuous confluence intervals,changing the number of main lanes and the input traffic volume,the road service level is used as the evaluation standard,and a reasonable combination of lane number matching is given.Finally,the model of the interweaving section is established.On the one hand,by setting different lengths of the interweaving section of the ramp entrance and exit to observe the impact on the main road capacity in the simulated road system,on the other hand,the service level of the interweaving area is divided according to the traffic density.Comprehensively study the influence of the length of the interlaced section on the matching of the number of main lanes.Through practical engineering examples,using the interweaving connecting section capacity calculation model to calculate the connecting section capacity of the case,combined with the VISSIM simulation analysis of the case,the case type interweaving connecting section capacity and service level are analyzed and evaluated.