research report

Dynamic Path-Based Equilibrium Assignment With Microscopic Traffic Simulation

Publication Date

April 1, 2005

Final Report

UCB-ITS-PRR-2005-13

Areas of Expertise

Abstract

This report summarizes research work conducted under TO4158 at the California ATMS Testbed of the Institute of Transportation Studies at the University of California, Irvine. Under this task order, the California ATMS testbed hosted two full-time PATH research postdocs (Henry Liu and Lianyu Chu) whose general responsibilities are focused on applications of ATMS in the Testbed environment. They are generally responsible for ensuring that the functional capabilities of the Testbed are designed, developed and maintained in a manner that complements and enhances the ATMS research objectives of the PATH program. Under the direction of PATH faculty researchers at UCI and the Testbed management team, they are generally responsible for software enhancements to the Laboratory “bench-top” system for modeling and evaluating ATMS, particularly with the microscopic simulation model Paramics. They also provided Caltrans the on-call support and technical guidance on various Caltrans micro-simulation projects related to the Paramics plugin modules developed at UCI. In addition to the general responsibilities outlined above, the PATH Researchers have specific research projects. The specific research project conducted under this task order is to develop a path-based equilibrium assignment model with micro-simulator Paramics. Since off-the-shlef Paramics can only do the link-based assignment, no path information during the traffic assignment process is stored nor provided. This will bring difficulties in the ATMS evaluation particularly related to the route diversion because partial or full path information is needed to conduct this type of evaluation with Paramics. To overcome this difficulty, a path-based assignment model is developed using Paramics Application Programming Interfaces (API) functions. The model comprises the advantages of the analytical traffic assignment model and the good properties of the simulation tools, which can represented the real world more properly. Some key techniques, route choice plug-in, turn penalty consideration and methods of successive average, and etc., were applied in the model. The Paramics V4 was selected as the demonstration simulation tool. A real grid network in Tucson, Arizona, was designed to test the performance of the model, and the results showed that the model converged to the user equilibrium as expected.

Suggested Citation
Henry Liu, Lianyu Chu and Will Recker (2005) Dynamic Path-Based Equilibrium Assignment With Microscopic Traffic Simulation. Final Report UCB-ITS-PRR-2005-13. Institute of Transportation Studies, Irvine, p. 17p. Available at: https://escholarship.org/uc/item/5cp244f4.

Phd Dissertation

High coverage point to point transit (HCPPT): A new design concept and simulation-evaluation of operational schemes.

Abstract

This dissertation research proposes the development and evaluation of a new concept for high-coverage point-to-point transit systems (HCPPT ). Overall, three major contributions can be identified as the core of this research: the proposed scheme design, the development of sophisticated routing rules that can be updated in real-time to implement and optimize the operation of such a design, and the implementation of a multi-purpose simulation platform in order to simulate and evaluate such a design under real network conditions. The design is based on Shuttle-style operations with a large number of deployed vehicles under a coordinated transit system that uses advanced information supply schemes with fast routing and optimization schemes. The system design is rather innovative and ensures that no more than one transfer is needed for the travelers, by using transfer hubs as well as reroutable and non-reroutable portions in the vehicles’ travel plans. It yields flexibility for demand-side benefits from options such as price incentives for time-bound “passenger-pooling” at the stops without destination constraints, by the users. A strict optimization formulation and solution for such a problem is computationally prohibitive in real-time. The design proposed in this dissertation is effectively geared towards a decomposed solution using detailed rules for achieving vehicle selection and route planning. If real-time update of probabilities based upon modeling the future dispatch decisions is included, then this scheme can be considered as a form of quasi-optimal predictive-adaptive control problem. Finally, a multi-purpose simulation platform is developed as part of this research in order to evaluate the performance of the system. The final simulations of HCPPT required point-to-point vehicle simulation, which is not possible with off-the-shelf simulators. The simulation framework uses a well-known microscopic traffic simulator that was significantly modified for demand-responsive vehicle movements and passenger tracking. A simulated case study in Orange County showed that with enough deployed vehicles, the system can be substantially better, even competitive with personal auto travel, compared to the often-unsuccessful traditional DRT systems and the existing fixed route public transit. Furthermore, HCPPT can be incrementally implemented by contracting out services to existing private operators.

Suggested Citation
Christian Cortes (2003) High coverage point to point transit (HCPPT): A new design concept and simulation-evaluation of operational schemes.. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991035093193604701.

conference paper

Evaluation of feedback and feedforward coupling of synthetic aperture navigation with LTE signals

2019 IEEE 90th vehicular technology conference (VTC2019-Fall)

Publication Date

September 1, 2019
Suggested Citation
Ali A. Abdallah and Zaher M. Kassas (2019) “Evaluation of feedback and feedforward coupling of synthetic aperture navigation with LTE signals”, in 2019 IEEE 90th vehicular technology conference (VTC2019-Fall). IEEE. Available at: 10.1109/vtcfall.2019.8891521.

Phd Dissertation

A new framework for optimal freeway ramp control

Suggested Citation
Michael Zhang (1995) A new framework for optimal freeway ramp control. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991012139499704701.

working paper

Geographic Scalability and Supply Chain Elasticity of a Structural Commodity Generation Model Using Public Data

Publication Date

October 1, 2012

Working Paper

UCI-ITS-WP-12-4

Areas of Expertise

Abstract

Freight forecasting models are data intensive and require many explanatory variables to be accurate. One problem, particularly in the United States, is that public data sources are mostly at highly aggregate geographic levels, while models with more disaggregate geographic levels are required for regional freight transportation planning. Second, supply chain effects are often ignored or modeled with economic input-output models which lack explanatory power. This study addresses these challenges by considering a structural equation modeling approach, which is not confined to a specific spatial structure as spatial regression models would be, and allows for correlations between commodities. A FAF-based structural commodity generation model is specified and estimated and shown to provide a better fit to the data than independent regression models for each commodity. Three features of the model are discussed: indirect effects, supply chain elasticity, and intrazonal supply-demand interactions. A validation of the geographic scalability of the model is conducted using data imputed with a goal programming method.

Suggested Citation
Fatemeh Ranaiefar, Joseph Y.J. Chow, Daniel Rodriguez-Roman, Pedro V. Camargo and Stephen G. Ritchie (2012) Geographic Scalability and Supply Chain Elasticity of a Structural Commodity Generation Model Using Public Data. Working Paper UCI-ITS-WP-12-4. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/6hz8v1wx.

published journal article

Hurricane threat in Florida: Examining household perceptions, beliefs, and actions

Environmental Hazards

Publication Date

January 1, 2017

Author(s)

Victoria Basolo, Laura J. Steinberg, Stephen Gant
Suggested Citation
Victoria Basolo, Laura J. Steinberg and Stephen Gant (2017) “Hurricane threat in Florida: Examining household perceptions, beliefs, and actions”, Environmental Hazards, 16(3), pp. 253–275. Available at: 10.1080/17477891.2016.1277968.

Preprint Journal Article

On Optimizing Shared-ride Mobility Services with Walking Legs

Abstract

Shared-ride mobility services that incorporate traveler walking legs aim to reduce vehicle-kilometers-travelled (VKT), vehicle-hours-travelled (VHT), request rejections, fleet size, or some combination of these factors, compared to door-to-door (D2D) shared-ride services. This paper provides a review of shared-ride services with walking legs (SRSWL), particularly the studies in the literature that model the operational problem(s) associated with SRSWL. The paper describes the operational and societal benefits of SRSWL as well as compares the SRSWL to circuitous D2D shared-ride services, ride-hailing services, and fixed-route transit services, in terms of VKT and traveler walking distance. The paper then delineates the operational subproblems associated with the SRSWL and discusses their computational complexity. Additionally, the review classifies configurations of SRSWL based on flexibility in assigning travelers to pickup and drop-off locations. The paper also discusses four modelling challenge: short-distance person trips, drop-off location choice for a vehicle’s last remaining passenger, allowing vehicles to wait for travelers at pickup locations, and simultaneously reducing VHT/VKT and improving customer service quality relative to D2D shared-ride services. The review paper concludes by discussing the most critical areas of future research related to SRSWL.

Suggested Citation
Zifan Wang, Michael F. Hyland, Younghun Bahk and Navjyoth JS Sarma (2022) “On Optimizing Shared-ride Mobility Services with Walking Legs”. arXiv. Available at: 10.48550/arXiv.2201.12639.

policy brief

Transitioning to Electric Drayage Trucks May Help Avoid Adding New Freeway Lanes to Freight Corridors in Southern California

Abstract

Much has been written about the potential benefits of electric and connected vehicles. However, one important, but often overlooked, implication of electrifying trucks is that if they are powerful enough (such as the Tesla semi), they can eliminate the moving bottleneck or queuing effect created by slow-moving conventional heavy-duty trucks because electric trucks are much more responsive compared to conventional diesel trucks because electric motors provide maximum torque from a standstill. This could substantially increase road capacity in areas with high commercial truck traffic, especially around major ports or logistics complexes, thus alleviating the need to add new lanes to local freeways.

Suggested Citation
Jean-Daniel Saphores and Monica Ramirez-Ibarra (2024) Transitioning to Electric Drayage Trucks May Help Avoid Adding New Freeway Lanes to Freight Corridors in Southern California. Policy Brief. UC ITS. Available at: https://doi.org/10.7922/g2f769wd.

working paper

Toward a Dynamic Model of Individual Activity Pattern Formulation

Publication Date

July 1, 1981

Working Paper

UCI-ITS-WP-81-4, UCI-ITS-AS-WP-81-2

Abstract

This paper presents preliminary thoughts on the development of a theoretical model of complex travel/activity behavior that incorporates both spatial and temporal constraints. The theoretical model is based on the use of individual activity patterns to represent complex travel/ activity behavior and assumes the form of a stochastic multiobjective dynamic programming model. A multiobjective dynamic programming approach is utilized due to the presence of conflicting objectives and the influence that past activity/travel decisions have on future choices. 

Suggested Citation
Gregory S. Root and Will Recker (1981) Toward a Dynamic Model of Individual Activity Pattern Formulation. Working Paper UCI-ITS-WP-81-4, UCI-ITS-AS-WP-81-2. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/7t72q459.

conference paper

Unifiable multi-commodity kinematic wave model

Transportation research procedia

Publication Date

January 1, 2017

Author(s)

Suggested Citation
W.-L. Jin (2017) “Unifiable multi-commodity kinematic wave model”, in Transportation research procedia, pp. 137–156. Available at: 10.1016/j.trpro.2017.05.009.