Model and algorithm of stochastic dynamic traffic assignment based on dynamic rainfall intensity

2021 ◽  
pp. 1-11
Author(s):  
Xun Ji ◽  
Chunfu Shao
Keyword(s):  
Cost Function ◽  
Traffic Flow ◽  
Rainfall Intensity ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
Dynamic Network ◽  
Travel Cost ◽  
Stochastic Dynamic ◽  
Dynamic Traffic ◽  
Rainy Weather

Frequent occurrence of urban rainy weather, especially rainstorm weather, affects transportation operation and safety, so it is essential that effective intervention measures to recover disordered traffic be adopted and then analyzed for their influence on the dynamic network. Therefore, models and algorithm to show dynamic traffic flow of traffic network in rainy weather are a fundamental need and have drawn great interest from governments and scholars. In this paper, innovative content contains a travel cost function considering rainfall intensity; considering the travel cost function, a dynamic traffic assignment model based on dynamic rainfall intensity is built. Then a corresponding algorithm is designed. Moreover, this study designs three scenarios under rainfall and analyzes the influence of the rainfall on an example network. The results show that rainfall has a significant effect on traffic flow. The finding proved the proposed models and algorithm can express the development trend of path flow rate on a dynamic network under rainfall.

scholarly journals A Dynamic Traffic Assignment Model for the Sustainability of Pavement Performance

2018 ◽  
Vol 11 (1) ◽  
pp. 170 ◽  
Author(s):  
Xinhua Mao ◽  
Jianwei Wang ◽  
Changwei Yuan ◽  
Wei Yu ◽  
Jiahua Gan
Keyword(s):  
Travel Time ◽  
Traffic Flow ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
Heavy Traffic ◽  
Pollutant Emissions ◽  
Pavement Performance ◽  
Dynamic Traffic ◽  
Teaching Learning ◽  
Pavement Damage

Existing Dynamic Traffic Assignment (DTA) models assign traffic flow with the principle of travel time, which are easy to distribute most of the traffic flows on the shortest path. A serious unbalance of traffic flow in the network can speed up pavement deterioration of highways with heavy traffic, which influences the sustainability of pavement performance and increases maintenance expenditures. The purpose of this research is to obtain a more optimized traffic assignment for pavement damage reduction by establishing a multi-objective DTA model with the objectives of not only minimum travel time but minimum decline of Present Serviceability Index (PSI) for pavements. Then, teaching-learning-based optimization (TLBO) algorithm is utilized to solve the proposed model. Results of a case study indicate that a more balanced traffic flow assignment can be realized by the model, which can effectively reduce average PSI loss, save maintenance expenditures, extend pavement service life span, save fuel consumption and reduce pollutant emissions in spite of a little increase of average travel time. Additionally, sensitivity of weight factor for the two objective functions is analyzed. This research provides some insights on methods on sustainable pavement performance.

scholarly journals Continuum Dynamic Traffic Assignment Model for Autonomous Vehicles in a Polycentric Urban City with Environmental Consideration

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Bosheng Rong ◽  
Hui Zhao ◽  
Shaohua Cui ◽  
Cuiping Zhang
Keyword(s):  
Urban Areas ◽  
Autonomous Vehicles ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
Travel Cost ◽  
Solution Algorithm ◽  
Dynamic Traffic ◽  
Environment Impact ◽  
Urban City ◽  
Assignment Model

This paper proposed a continuum dynamic model for autonomous vehicles in a polycentric urban city by considering the environment impact of traffic emission. The model assumes that homogeneous autonomous vehicles are continuously distributed over the urban areas which tend to choose a path to minimize their total travel cost from origin to destination. To describe the path choice behavior of travelers, we presented the continuum dynamic traffic assignment model which consists of a two-dimensional hyperbolic system of nonlinear conservation laws with source terms and an Eikonal-type equation. The elastic demand is considered using a function which associating each copy of flow with its total instantaneous travel cost. For the environmental impacts, here we consider the influence of CO emission and include the cost of emission into the actual transportation cost. A solution algorithm for the model is designed as a cell-centered finite volume method for conservation law equations and a fast sweeping method for Eikonal-type equations on unstructured grids. Numerical examples are given to demonstrate the model and the proposed solution algorithm. Further, the results of the travel cost considering CO emissions and not considering CO emissions are compared.

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