published journal article
Archives: Research Products
conference paper
Characteristics of speed dispersion and its relationships with the fundamental traffic flow parameters in urban freeways: A case study in northern California
Proceedings of the 89th annual meeting of the transportation research board
Publication Date
Author(s)
Abstract
This research reveals statistical characteristics of speed dispersion and its relationships with fundamental traffic flow parameters in northern California. Nearly a quarter million vehicle observations of a five-lane urban freeway are examined individually by lane and aggregately for a total of seven categories. Speed dispersion is measured by coefficient of variation of speed (CVS) and standard deviation of speed (SDS). CVS displays an exponential form of occupancy or space mean speed, and is two-phase linear to flow. Variation of CVS is stable and similar across lanes during light traffic, and afterward increases and diverges into three groups. SDS in contrast does not present any simple equation of the fundamental parameters. Both CVS and SDS of the all lane mix are greater than those of other categories given fixed occupancy or mean speed.
Suggested Citation
Chih-Lin Chung and Will Recker (2010) “Characteristics of speed dispersion and its relationships with the fundamental traffic flow parameters in urban freeways: A case study in northern California”, in Proceedings of the 89th annual meeting of the transportation research board, p. 19p.policy brief
Perceptions of Neighborhood Change in a Latinx Transit Corridor
Publication Date
Associated Project
Author(s)
Abstract
Understanding how residents feel about neighborhood changes due to new development along transit corridors (often referred to as transit-oriented development) remains understudied despite growing concerns over displacement and gentrification. Studies that examined these concerns are largely based on analyzing land use, housing values, and socio-economic shifts (i.e., who is moving in and out of neighborhoods), and do not provide conclusive evidence that transit-oriented development (TOD) is linked to neighborhood gentrification and displacement. Prior surveys of residents living near transit indicate a generally positive assessment of TOD in terms of improved walkability and accessibility but also express concerns over pedestrian safety and parking related to increased traffic and new commercial development. However, recent studies counter this relatively positive assessment of TOD, particularly among activists and community organizers in low-income communities of color.
Suggested Citation
Douglas Houston and Michelle E. Zuniga (2024) Perceptions of Neighborhood Change in a Latinx Transit Corridor. Policy Brief. UC ITS. Available at: https://doi.org/10.7922/g2j67f9d.
Published Journal Article: Bootstrap confidence bands for shrinkage estimators
research report
The coordination of functional areas within transit agencies through networks of managerial and professional interaction
Publication Date
Associated Project
Author(s)
Final Report
Areas of Expertise
Suggested Citation
William B. Stevenson (1985) The coordination of functional areas within transit agencies through networks of managerial and professional interaction. Final Report UMTA-CA-11-0028-2. Washington, D.C. : Springfield, VA: U.S. Department of Transportation, Urban Mass Transportation Administration, Office of Technical Assistance, University Research and Training Program ; National Technical Information Service [distributor. Available at: https://catalog.hathitrust.org/Record/012354483.working paper
Classification Analysis of Traffic Improvement Sites
Publication Date
Author(s)
Abstract
This paper presents results of an application of the case study approach to the evaluation of alternate TSM strategies. The procedure is useful in the classification of potential sites relative to their expected performance following implementation of specific TSM strategies designed to improve flow conditions. The specific focus of the paper is on the use of classification analysis as a means of transferring analysis results drawing from a small number of representative case studies to a broader range of alternate applications. This approach is shown to provide a reasonable and less costly alternative to individual site-by-site analyses.
Suggested Citation
Will Recker, Gregory S. Root and Michael G. McNally (1985) Classification Analysis of Traffic Improvement Sites. Working Paper UCI-ITS-WP-85-6. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/1gn830g5.research report
Simulation of ITS on the Irvine FOT Area Using "Paramics 1.5" Scalable Microscopic Traffic Simulator: Phase I: Model Calibration and Validation
Publication Date
Associated Project
Author(s)
Final Report
Areas of Expertise
Abstract
In this research, a promising ITS-ready microscopic traffic simulator, Paramics1.5, is thoroughlyevaluated both subjectively and objectively in preparation for its use for modeling ITS in SouthernCalifornia. A general and comprehensive list of requirements (evaluation template) for amicroscopic traffic flow simulator to successfully model ITS was first compiled and presented. Theevaluation template covered various aspects of modern transportation network modeling, including:[1] supply/control aspects, [2] demand/behavior aspects, [3] environmental-related aspects, and [4]simulator-performance aspects. The template was applied to Paramics1.5, a new and potentiallysuccessful ITS-oriented micro-simulator. The evaluation revealed Paramics1.5’s capabilities andlimitations as an ITS modeling tool. It was concluded that Paramics1.5 is an excellent ‘shell’ or‘framework’ for a comprehensive and extensive transportation simulation laboratory. Paramics1.5offers two very important and unprecedented features: high performance and scalability. To ourknowledge, this is the most promising approach to handle realistic real word traffic networks underITS. Also, Paramics1.5 offers very plausible detailed modeling for many components of theenvisioned ‘ideal’ simulator. Nevertheless, several limitations were also identified and discussed.Suggestions for improvements were also presented. Improving such limitations requires both directmodifications in the software itself, and maturation of the Application Programming Interface(API), one of Paramics1.5’ most important capabilities. The subjective evaluation was also followedby an objective evaluation based calibration of key driving-behavior parameters underlying -amongother things- the car following and lane changing models of the simulator.Calibration wasconducted using real traffic data from the California Testbed, headquartered at the University ofCalifornia Irvine. The calibrated model performed well during validation on a freeway link. On afull network, the vehicle release mechanism showed some time-lag in releasing demand onto thenetwork. This is potentially due to stacking of vehicles in memory before adequate headways arefound on the road to release the vehicles. Although the problem itself is simple, its effects on theresults were notable.
Suggested Citation
Baher Abdulhai, Jiuh-Biing Sheu and Will Recker (1999) Simulation of ITS on the Irvine FOT Area Using "Paramics 1.5" Scalable Microscopic Traffic Simulator: Phase I: Model Calibration and Validation. Final Report UCB-ITS-PRR-99-12. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/2ks86938.conference paper
Using interactive simulation to model driver behavior under ATIS
Proceedings of the Fourth International Conference on Micrcomputers in Transportation
Publication Date
Author(s)
Suggested Citation
Jeffrey L. Adler, Wilfred W. Recker and Michael G. McNally (19983) “Using interactive simulation to model driver behavior under ATIS”, in Proceedings of the Fourth International Conference on Micrcomputers in Transportation. Baltimore, MD, pp. 344–355.published journal article
Greedy motion planning for simultaneous signal landscape mapping and receiver localization
IEEE J. Sel. Top. Signal Process.
Publication Date
Author(s)
Suggested Citation
Zaher M. Kassas, Ari Arapostathis and Todd E. Humphreys (2015) “Greedy motion planning for simultaneous signal landscape mapping and receiver localization”, IEEE J. Sel. Top. Signal Process., 9(2), pp. 247–258. Available at: 10.1109/jstsp.2014.2387101.published journal article