Study On Freeway Tunnel Traffic Flow Model And Emergency Traffic Control Plans

With the extending from plain region to mountainous area of China’s freewayconstruction projects, the number of long tunnels and extra-long tunnels is increasing year byyear. As the special sections of mountainous freeway, the studies of traffic safety and trafficcontrol under emergency have always been concerned. Especially traffic control strategies offreeway tunnels under emergencies and related emergency plan researches, which can perfectand strengthen the incident emergency disposal work of mountainous area freeway tunnels.This dissertation carries out the study on freeway tunnel traffic flow model and emergencytraffic control strategies research from four aspects, including the microscopic traffic flowmodeling and simulation of freeway tunnels, the classification and grading methods offreeway emergencies, the generation method of emergency traffic control strategies offreeway tunnel, and the evaluation of tunnel emergency traffic control plans.(1) To model and simulate the microscopic traffic flow in freeway tunnels, variousfactors which influenced the status of vehicles’ in freeway tunnels were analyzed, from theangles of traffic engineering hierarchies and facilities allocation of freeway tunnels, and asingle lane traffic flow microscopic model based on the single lane cellular automatamodel--NS model was put forward, considering the speed limit and the environmental impactof freeway tunnels. Also, based on the two-lane cellular automata model--STNS model, atwo-lane traffic flow microscopic model of freeway tunnels was put forward, considering bothsymmetric lane-changing rules and asymmetric lane-changing rules. Through the numericalsimulation, as the traffic bottleneck in freeway, the influence of tunnels on the traffic flow andthe vehicles’ average speed of tunnel area were analyzed, and the simulation results show thatfreeway tunnels can reduce the vehicles’ average speed of the corresponding sections, and hasa smoothing effect to the traffic flow.(2) In order to solve the problem that the existing freeway emergency classificationmethod does not contain the incidents which not only can bring impacts on the normalfreeway traffic flow, but also can be anticipated, such as holiday traffic and road maintenance projects, based on the predictability of incidents, a novel freeway emergency classificationmethod was put forward, which divided the freeway incidents into two kinds including crisisevents and early warning events. For the problems that the existing freeway emergencygrading method was usually based on some index which were difficult to determine at thebeginning of the incident, and the method cannot cover freeway daily emergencies, a novelfreeway emergency grading method, which added a fifth grade named daily incidents to thefour grades of existing grading method, was put forward, and the emergency influence on thenormal freeway traffic flow were analyzed from the angle of emergency traffic control.(3) As the existing emergency traffic control plan can’t make full use of the historicalexperience in existing emergency traffic control, based on the study of freeway tunnel basictraffic control strategies, a novel traffic control strategy generating method for freeway tunnelemergencies was put forward, which combined two kinds of reasoning mechanism ofcase-based reasoning and rule-based reasoning. This method can strengthen the practicabilityand effectiveness of emergency plans, and the traffic control strategy generating method weresimulated and analyzed in a2D simulation platform for freeway tunnel traffic control andguidance.(4) For the evaluation of emergency traffic control plans, two comprehensive indexsystems of plan evaluation were put forward. One is to evaluate the emergency plan beforeimplementation, the other is to evaluate after implementation. The emergency traffic controlplan disposal process were analyzed based on the application of network in projectmanagement, and the relationships of the emergency disposal process were analyzed throughthe network critical path analysis, and finally the emergency traffic control planimplementation effect was evaluated.In the end of this dissertation, conclusions and prospects were given.