An Assessment Scheme for Road Network Capacity under Demand Uncertainty

Abstract

Network capacity is a vital index with which to assess the operation of traffic networks. The majority of existing traffic network capacity models are formed as bi-level programming, which maximizes the traffic flows under equilibrium constraints and is extremely dependent on the current origin–destination (O–D) travel demand. However, an accurate O–D matrix is not easy to obtain in practice. This article aims to provide an assessment method for traffic network capacity under demand uncertainty. To consider the variation in real demand in traffic networks, the current travel demand is treated as unknown parameters that are defined inside a restricted set. Based on the hypothesis of different probability distributions, the road network capacity is calculated by repeated capacity loading experiments with a random sampling of uncertain parameters. To improve the efficiency of the repeated calculations of the traffic assignment model, a sensitivity-analysis-based (SAB) approximation method was developed to avoid the double calculation of the network capacity model for each random O–D matrix. The SAB method significantly improved the calculation efficiency while ensuring accuracy. Using simulation experiments, we researched the reliability of road network capacity and the probabilities of high congestion for each link under uncertain demand.

Improving the Maritime Traffic Evaluation with the Course and Speed Model

“…This method involves surveying observation points, either manually or with machines, to extract data samples. The collected data are then compared with screen line survey results and household interviews to validate the survey's accuracy [2,3].…”

A Path Recommendation Method Considering Individual Driving Preferences

“…The i th indicator is extremely more important than the jth indicator. 2,4,6,8 Intermediate values between the two adjacent scales from those listed above.…”

“…The fundamental problem underlying traffic congestion is the mismatch between traffic supply and demand, in terms of both time and space. Therefore, to address traffic congestion, it is necessary to consider solutions from both the supply [4,5] and demand sides [6,7]. While increasing the traffic supply can be achieved through expanding the length and density of roads, it cannot provide immediate relief.…”