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Open Access Research Article Issue
Formulation and solution for calibrating boundedly rational activity-travel assignment: An exploratory study
Communications in Transportation Research 2023, 3: 100092
Published: 20 January 2023
Downloads:3

Parameter calibration of the traffic assignment models is vital to travel demand analysis and management. As an extension of the conventional traffic assignment, boundedly rational activity-travel assignment (BR-ATA) combines activity-based modeling and traffic assignment endogenously and can capture the interdependencies between high dimensional choice facets along the activity-travel patterns. The inclusion of multiple episodes of activity participation and bounded rationality behavior enlarges the choice space and poses a challenge for calibrating the BR-ATA models. In virtue of the multi-state supernetwork, this exploratory study formulates the BR-ATA calibration as an optimization problem and analyzes the influence of the two additional components on the calibration problem. Considering the temporal dimension, we also propose a dynamic formulation of the BR-ATA calibration problem. The simultaneous perturbation stochastic approximation algorithm is adopted to solve the proposed calibration problems. Numerical examples are presented to calibrate the activity-based travel demand for illustrations. The results demonstrate the feasibility of the solution method and show that the parameter characterizing the bounded rationality behavior has a significant effect on the convergence of the calibration solutions.

Open Access Research Article Issue
Space–time prisms in multimodal supernetwork - Part 2: Application for analyses of accessibility and equality
Communications in Transportation Research 2022, 2 (1): 100063
Published: 04 May 2022
Downloads:20

Space–time prism (STP) is a fundamental concept in time geography and has been predominately constructed in unimodal transportation networks. Due to the vast trip chaining options by private vehicles and public transportation, it was challenging to construct STP over multimodal transportation networks. We previously put forward an efficient method to narrow down the action space for trip chaining and construct STPs effectively in a multimodal supernetwork. This study applies multimodal STP modeling to measure space–time accessibility and equality of daily activity opportunities. Two equality measures (Gini coefficient and 20:20 ratio) are derived from two space–time accessibility measures based on delineated STPs. We examine the equality of access to shopping and leisure opportunities in the Rotterdam–The Hague metropolitan area, the Netherlands. The results show the effects of various factors on accessibility and equality. It is found that although the study area has relatively low inequality using single modes, multimodal trip chaining further reduces inequality to access the distributed space–time opportunities.

Open Access Research Article Issue
Space–time prism in multimodal supernetwork - Part 1: Methodology
Communications in Transportation Research 2021, 1 (1): 100016
Published: 09 December 2021
Downloads:64

Space–time prism (STP) modeling offers a theoretical base for various person-based space–time accessibility measures. It has been challenging to construct STPs in multimodal transportation networks because of the vast multimodal trip chaining options between private vehicles and public transportation. This study suggests an effective method for narrowing down the trip chaining space. The method involves three incremental strategies to eliminate parking locations that contribute little to enlarging the STP. First, an upper bound potential path area (PPA) is constructed to remove all inferior parking locations. Second, the study area is partitioned and only complementary parking locations attractive to trip chaining are selected. Third, triangular inequalities are applied for pruning. The selected parking locations are used to construct a compact multimodal supernetwork encompassing one episode of activity participation. Consequently, the STP and PPA can be found by an existing two-stage bidirectional search method. Experimental tests are conducted to demonstrate the effectiveness of the method. It is found that 1–2 orders of speedups can be achieved with little compromising the accuracy of measuring space–time accessibility. The suggested method is applicable for measuring space–time accessibility in large-scale multimodal transportation networks.

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