Modeling

Hierarchical Analysis of Spreading Dynamics in Complex Systems

Kasliwal, Aparimit
Alhadlaq, Abdullah
Salgado, Ariel
Ganguly, Auroop R.
Marta Gonzalez
2025

Modeling spreading dynamics on spatial networks is crucial to addressing challenges related to traffic congestion, epidemic outbreaks, efficient information dissemination, and technology adoption. Existing approaches include domain-specific agent-based simulations, which offer detailed dynamics but often involve extensive parameterization, and simplified differential equation models, which provide analytical tractability but may abstract away spatial heterogeneity in propagation patterns. As a step toward addressing this trade-off, this work presents a hierarchical multiscale framework...

Assessing Public Health Benefits of Replacing Freight Trucks with Cargo Cycles in Last Leg Delivery Trips in Urban Centers

Hartle, J
Elrahman, O
Wang, C
Rodriguez, Daniel
Ding, Y
McGahan, M
2022

Increased urbanization, population growth, and demand for time-sensitive deliveries means increased freight movement in cities, which contributes to emissions, noise, and safety concerns. One innovative mode gaining widespread attention for urban deliveries is cargo cycles—bicycles adapted for freight delivery. Despite the recognized potential and possible success of transporting at least 25% of freight via cycle, research remains limited. This research investigates the potential of cargo cycle delivery for last mile freight in Oakland, California, with a focus on the West Oakland...

A Spatial Agent-Based Model for the Simulation of Adults' Daily Walking Within a City

Yang, Y
Roux, AV Diez
Auchincloss, AH
Rodriguez, Daniel
Brown, DG
2011

Environmental effects on walking behavior have received attention in recent years because of the potential for policy interventions to increase ...

Safe Learning MPC With Limited Model Knowledge and Data

Kandel, Aaron
Moura, Scott
2024

This article presents an end-to-end framework for safe learning-based control (LbC) using nonlinear stochastic MPC and distributionally robust optimization (DRO). This work is motivated by several open challenges in LbC literature. Many control-theoretic LbC methods require subject matter expertise (SME), often manifested as preexisting data of safe trajectories or structural model knowledge, to translate their own safety guarantees. In this article, we focus on LbC where the controller is applied directly to a system of which it has no or extremely limited direct experience, toward safety...

Assessment of Traffic Simulation Models : Final Report

Alexander Skabardonis
University of California, Berkeley
Washington State Department of Transportation
1999

This report describes a study which focused on the selection and application of traffic simulation models. The models were evaluated for: capabilities and features, input data requirements, output options, relationship with traditional planning and operational analysis tools, and modeling effort and costs.

Application of Simulation to Evaluate the Operation of Major Freeway Weaving Sections

Alexander Skabardonis
Cassidy, M
May, A D
Cohen, S
1989

This paper describes the findings from the application of the INTRAS microscopic simulation model to evaluate the traffic performance at major freeway weaving sections. The work performed is part of an ongoing research project to develop improved weaving analysis procedures that are particularly applicable to California conditions. The INTRAS model was modified to predict the speeds of weaving and nonweaving vehicles and applied on eight major freeway weaving sections for a range of traffic conditions at each site. Good agreement was obtained between the measured and predicted values....

A Spatial Queuing Model for the Emergency Vehicle Districting and Location Problem

Geroliminis, Nikolas
Karlaftis, Matthew G
Alexander Skabardonis
Transportation Research Part B: Methodological
2009

Emergency response systems in urban areas should be located to ensure adequate coverage and rapid response time. The authors develop a model for locating emergency vehicles on urban networks considering both spatial and temporal demand characteristics such as the probability that a server is not available when required. The authors also consider that service rates are not identical but may vary among servers and are dependent upon incident characteristics; corresponding districting and dispatching problems are also integrated in the location model. The model is applied using real data for...

Assessing the Traffic Impacts of Transportation and Land Development Scenarios

Deakin, E A
Alexander Skabardonis
Walukas, E
Transportation Studies
1985

This paper demonstrates the use of the transyt model in assessing the traffic impacts of transportation and land development scenarios. Using the downtown area of the city of Berkeley as a case example, the effects of overall traffic growth, project-specific traffic increases, alternative parking policies, tsm programs, and street and intersection design changes are explored. The results show that once transyt is calibrated for an area, it can be applied relatively quickly and inexpensively as a sketch-planning tool. (a) (Author/TRRL)

TRANSYT Display: A Graphics Package for Signal Timing

Loubal, P S
Alexander Skabardonis
Wingerd, L
May, A D
Torregrosa, L
STUDIES
1985

This report describes the development and application of transyt display, an interactive microcomputer program to produce plots of a signalized network and its input and output values from the widely used transyt simulation and optimization model. The program can display on a monitor screen both input data and measures of traffic performance for each link and node of the particular network. Any display can be printed, and the user has considerable flexibility in selecting plot size, and including captions to the plot. The report presents several applications of the program. Future program...

Modelling the Traffic Behavior at Grade-Separated Interchanges

Alexander Skabardonis
Printerhall Limited
Traffic Engineering & Control
1985

Grade separation is an essential feature of intersections between motorways and other high-capacity roads. This paper describes the development of a microscopic simulation model to investigate the interactions between traffic and geometric variables at such situations. The model has been integrated within a modular computer program and it has been calibrated and validated with a large data-base. Comparisons with measured data and information from other sources have shown that the model adequately describes the traffic behaviour. (Author/TRRL)