Study On Urban Parking Flow Assignment Model Under Stochastic Network

Due to the shortage and uneven distribution of urban parking spaces,a considerable part of urban traffic flows are vehicles that patrol in search of parking spaces after arriving at their destinations.The existence of cruising vehicles will not only increase the burden on the urban road network but even cause local traffic congestion.Therefore,the reasonable allocation of parking cruise traffic in the urban road network is of great significance to alleviate the problem of "parking difficulties" and "road congestion" in the city.Most existing parking flow allocation models ignore the uncertainty of parking lot availability and the uncertainty of route travel and parking search delay in the parking selection process.These uncertainties directly affect travelers' parking choice behavior.Therefore,this paper studies the urban parking flow allocation model based on these two uncertainties.The main contents are as follows:(1)Analysis of parking decision.The characteristics of parking facilities are analyzed in detail from the aspects of parking space attributes and parking features,and the travel decision methods of travelers are introduced in detail,including travel path decision methods and parking facility decision methods,and finally the factors which have an influence on traveler parking decisions are analyzed and described.(2)Parking SUE model considering the available probability of parking lot based on queuing theory.Given the uncertainty of parking lot availability,the parking search route is first defined,then the G / G / c / FCFS parking queuing model is established.The relationship between the parking lot availability probability,path flow,and travel time is analyzed.And a generalized cost function of the parking search route considering the probability of parking lot is re-established,and then a parking flow allocation model based on the G / G / c / FCFS parking queuing model is proposed,which's solving algorithm is given in this paper.The results of the example show that: compared with the parking flow allocation model that does not consider the parking lot availability probability,this model improves the parking lot utilization rate by about 22.7%,which can effectively alleviate the local traffic congestion caused by parking cruise traffic.(3)Parking SUE model with the uncertainty of road link delay and parking search delay.Aiming at the uncertainty of road link and parking search delay,the traveler's parking choice behavior is first described,and then the uncertainty of the road link and parking search delay in the process of traveler parking choice is analyzed.Among them,probability theory knowledge is used to deal with the uncertainty of road link delay.Robust optimization knowledge is used to deal with the uncertainty of parking search delay,and the uncertainty upper bound function of parking search delay is determined.Then,the cost of the road section and parking search(T-PS)is defined,and the T-PS cost function under the uncertainty of the road link and parking search delay is given.Finally,the parking stochastic user equilibrium model under uncertain road link and parking search delays is constructed in combination with parking fee and walking costs,which proves the existence and equivalence of model solutions,and the adaptive dichotomy(SAB)solution algorithm is proposed.The numerical example results show that the solution obtained by the SAB algorithm satisfies the equilibrium conditions of the model.Compared with the parking flow allocation model without considering the road link and parking search delay,the model in this paper is more in line with the actual parking choice behavior of travelers.