Location Optimization And Dynamic Information Releasing For Urban Parking Variable Message Sign Using Agent-based Simulation

In large and medium-sized cities at home and abroad,parking spaces are scarce public resources presently.Especially in the urban center area,they are usually high-saturated utilized or even fully occupied during peak hours.Parking problem causes bad transportation conditions,traffic volume increase,spatial resource waste,fossil energy consumption,serious transportation pollutions,and does harm on people' physical and psychological health.Parking Variable Message Sign(PVMS),as a commonly used form of Parking Guidance and Information System(PGIS)display terminal,is generally equipped along the roadside and achieves rather good performances.An improved incremental assignment and an agent-based simulation were introduced to describe the process of cruising for available spaces dynamically.Basing on this,treating divarication intersections as one form of Main Decision Point(MDP)and a discriminated release method were proposed and then the PVMS location optimization and information releasing were evaluated.Finally,Xujiahui CBD,Shanghai was taken as an example to validate the proposed algorithm.The main work and the research results are summarized as follows.(1)An agent-based simulation was proposed to evaluate the performances of PGIS dynamically.In this study,each vehicle was treated individually as an autonomous agent with series of attributes,which can be divided into four categories: the basic,the spatial,the parking,and the statistic.By operating these attributes,the vehicles moving on the network dynamically and parking choice decision were conducted.(2)Treating divarication intersections as one form of the MDPs,and then an improved incremental assignment and the agent-based simulation were introduced to determine the spatial positions of the MDPs and the frequency of occurrence.Locating PVMSs at the MDPs can reflect the reassigning function of parking guidance service and meet drivers' requirements on the parking information,then the travel time decreases and the compliance ratio increases.Moreover,the key points of maximizing the parking utilities were well reflected and the location scenario would performance well in practical implements.Finally,take Sioux Falls network and Xujiahui CBD,Shanghai as examples to illustrate and validate the proposed location algorithm.(3)A discriminated release method and the process of determining the space occupancy indicator(SOI)were proposed.The discriminated release method is an asymmetric one in differing from the same information algorithm adopting the same SOI value for all parking lots.With the specified SOI value for each parking lot,the discriminated parking information was released.By iteratively modifying the SOI values,the parking demands were diverted uniformly among the parking lots and the parking guiding reliabilities was consequently promoted.Additionally,Xujiahui CBD,Shanghai was also taken as an example to validate the proposed release method.