بهبود شبكه هاي خياباني در ارتباط با وقوع تصادف ترافيكي در آنها

چكيده انگليسي :

Street Network Performance Improvement under Traffic Accident Occurrence Hamed Mahmood Abadi H mahmoodAbadi@cv iut ac ir Date of Submission 2011 04 27 Department of Civil Engineering Isfahan University of technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Sir Nader Shetab shetab@cc iut ac irAbstract Analysis of urban network performance under stochastic incident occurrences is a new subject intransportation literature Such incidents may be classified into three groups a events Such as traffic accidents which disrupt some parts of the network for a short period of time b events such as earth quakes which cause break down of elements of the network for a long time and c events causing changes in network capacity and ordemand which in turn fluctuate link or path traffic volume and hence travel time In the context of a above ameasure is constructed to evaluate the importance of the links in the network Given such importance andresource constraints a model has been formulated to prevent or delay accidents to happen and an algorithm isproposed to solve this problem This is an accident prevention AP problem Next based on the measure ofsuitable remaining trip hours and a measure of connectivity another problem is formulated with an objective toimprove the connectivity of the important but weakly connected node destination pairs of the network after anaccident occurrence This is an accident mitigation AM problem An algorithm is proposed to solve thisproblem The algorithms of AP and AM are applied on two small and medium size networks and the resultsare discussed Modeling problems in group b above has been initiated by constructing a model to improve theperformance of the networks to contain the negative impacts of the random events with long term effects Analgorithm is proposed to solve this problem to maximize the overall reliability of the network to withstand thosestochastic events under resource constraint Application of the proposed method over several networks is shownnumerically and the results are discussed In the analysis of the problems in group c above this dissertationdiscusses the random nature of volume and travel time of the links in the network particularly for the morningpeak trips which are basically comprised of those with trip purpose work and school These trips are suchthat they should be done before certain time and hence the respective trip makers are argued to have a pessimisticor conservative attitude in making them A new equilibrium flow problem called pessimistic equilibrium flowproblem PEF has been proposed to model such behavior in route choice in the network and a procedure isdevised to solve it Next a pessimistic network design PND problem has been proposed which minimizes anobjective function that is a linear combination of the travelers social cost and time cost and has its network flowsbased on PEF problem A procedure is devised to solve this problem Application of this procedure to solve aPND problem in a test network and comparison of the results obtained with the corresponding results obtained bysolving a conventional network design problem on the same test network reveals several interesting points discussed in this dissertation This dissertation is concluded by summing up the results obtained in this research and pointing several avenues for future research Key words stochastic events urban network traffic accident natural disasters trafficfluctuations network design

محمودآبادي، حامد

بهبود شبكه هاي خياباني در ارتباط با وقوع تصادف ترافيكي در آنها

حوادث غير منتظره , بلاياي طبيعي , طراحي شبكه