Parameters Study On The Collector-distributor Road In The Urban Cloverleaf Interchanges On Expressway

In order to realize urban traffic level improving as a whole, major cities fast roads also developrapidly.In urban expressway, the application of cloverleaf interchange is relatively common due to itscontinuous and natural traffic and beautiful symmetrical modeling.In order to eliminate interweave on thetrunk line, avoid double exports and make the mark simplified, improve the traffic capacity and drivingsafety, we often set collector-distributor road within the cloverleaf interchange layout on the outside ofmain entrances to arrangement the inward and outward, weaving section on the collector-distributor road,so it becomes a cloverleaf interchange with collector-distributor road. The corresponding technicalrequirements of the setting of collector-distributor road are not specified in current design specifications, sothis article conducts the research, provide theoretical basis and reference for the reasonable designThrough analysing the composition, types, interchange traffic characteristics and traffic capacity andservice level of collector-distributor road in the cloverleaf interchange, this article puts forward that thenecessity of setting collector-distributor road is determined by the analysis service level of weaving areaand some other factors which affect the setting of the collector-distributor road. Considering settingcollector-distributor road through the analysis of the various factors which affect the setting of thecollector-distributor road this article puts forward the determination method of each component of thecollector-distributor road, including the length calculation of the distributing lanes interweave area, gradualchange section length, and the gradual ramp feeder lane length, cross-sectional layout method, and thecontrol of interchange land. Finally through analysing design parameters of the Taiyi interchange at Xi’ansouth second ring road and through the on-the-spot traffic volume and traffic capacity conditionobservation and records, this article use the VISSIM simulation model carring on the simulation to Taiyiinterchange and find the traffic conditions is in conformity with the actual. Using the setting method ofcollector-distributor road proposed in this paper, we set the collector-distributor road lane on both sides ofTaiyi interchange, and carry on the simulation to verify the reliability of the conclusion in this papercompared with without setting collector-distributor road.