| The optimization strategies to improve urban traffic include a lot of short and long termadjustment: points, lines, surface of the road network; moving, static traffic; motorized andnon-motorized transport; the environment and the way of residents to travel; trafficparticipation and traffic management and so on. Most of measures of traffic management andcontrol to ease traffic congestion is based on empirical and are given after observation ofvarious phenomenons. As for why, rarely mention, which also led to the management style ofthe "stop-gap measuresâ€. Intersection as a key part of the urban road network, has become akey restricting the ability of the entire road network, and as such has been extensively studied,with regard to the improvement of the intersection. This article is part of the big problem.Starting from the problem of intersection traffic conflict, in particular, turning left at thetraffic in the entire intersection traffic status, it analyses the critical impact of turning trafficfor the intersection of complexity. For specific steering traffic restriction into prohibited turnleft and turn right and restrictions turn left and turn right four aspects of the programdiscussed research include: ban limited classification set conditions, specific set program,set-lane divided and width adjustment, signal conditioning, increase or decrease in the signsand markings and traffic guide program. For setting conditions point to study a lot ofliterature, by contrast settings before and after the delay, some specific numerical relationshiptable was given.A theoretical basis for the intersection turning left restriction modeling was providedthrough the introduction of the intersection network processing program on the basis of thesummary of the analysis set theory. Through the analysis of different traffic assignmentmodels, two models of the static allocation and dynamic allocation were introduced to build abi-level programming model, and the lower-level model is the ban limit set program cloth.Generally speaking, it is possible to set the left turn intersection ban limit is based on theactual phenomena observed thus establish the Restriction of the alternative set, optimalsolutions can be obtained through the0-1variables to solve the upper model The objectivefunction is to set the Restriction reduce overall network delay. Comparative analysis ofvarious traffic assignment models modeling algorithm, the solving of these models can beattributed to a complex mathematical problems.After the establishment of a bi-level programming model, it gives a specific example ofurban road traffic improvement. First, starting from the analysis of the old town of the city’straffic situation, the various sections of the status quo through the traffic survey data, adetailed analysis of the status quo operation of alternative prohibited from turning left setintersection, then constructed the selected study area specific model, restricted to modeling network scale the lower model chosen statically allocated, through the introduction ofintelligent algorithm to solve the reform issue, through simulation to verify the validity of theresults also shows that the model is reasonable. By the research of characteristicsclassification and steps of the traffic simulation, the micro-simulation software VISSIM andthe macro-simulation software TransCAD were selected from comparing the features and useof the field of traffic simulation software to check the solution results of the model. |
