research report

Maximizing the Air Quality and Environmental Justice Benefits of Zero Emission Off-road Vehicles and Equipment in California

Abstract

Diesel fuel powered off-road vehicles and equipment used in agriculture, construction, mining, and industry have significant air quality and public health impacts due to high levels of pollutant emissions. Replacing these with zero emission powertrains represents a key strategy for reducing the harmful environmental impacts. However, the air quality impacts of zero emission off-road vehicles have not been assessed. Using the CMAQ model, we find that fully converting the off-road sector to zero emission equipment can decrease annual PM2.5 up to 0.9 μg/m3 and reduce daily maximum 8-hr average (MDA8) ozone as much as 6 ppb in Southern California. Statewide, these improvements yield benefits to public health potentially ranging up to $22.0 billion annually. The results further demonstrate the ability of zero emission off-road equipment to achieve health benefits within socially and economically disadvantaged communities.

Suggested Citation
Michael MacKinnon, Kai Wu and Scott Samuelsen (2025) Maximizing the Air Quality and Environmental Justice Benefits of Zero Emission Off-road Vehicles and Equipment in California. Available at: https://ezid.cdlib.org/id/doi:10.7922/G21Z42SX (Accessed: September 16, 2025).

published journal article

Evaluation of information applications of a self-organizing distributed traffic information system for a large-scale real-world traffic network

Computer-Aided Civil and Infrastructure Engineering

Publication Date

November 1, 2008

Author(s)

Suggested Citation
Xu Yang and Will Recker (2008) “Evaluation of information applications of a self-organizing distributed traffic information system for a large-scale real-world traffic network”, Computer-Aided Civil and Infrastructure Engineering, 23(8), pp. 575–595. Available at: 10.1111/j.1467-8667.2008.00557.x.

research report

Fiscal and organizational impacts of part-time labor in public transit

Suggested Citation
Charles A. Lave, Genevieve. Giuliano and Kenneth M. Chomitz (1985) Fiscal and organizational impacts of part-time labor in public transit. Washington, DC: Office of Service and Management Demonstrations, Urban Mass Transportation Administration : Distributed in cooperation with Technology Sharing Program, Office of the Secretary of Transportation. Available at: https://catalog.hathitrust.org/Record/010607876.

conference paper

One Year into the Pandemic: Heterogeneity in COVID- 19 Spread Patterns and Human Mobility Characteristics across US Counties

101st Annual Meeting of the Transportation Research Board (TRB)

Publication Date

January 1, 2022

Author(s)

Yusuf Sarwar Uddin, Rezwana Rafiq
Suggested Citation
Md Yusuf Sarwar Uddin and Rezwana Rafiq (2022) “One Year into the Pandemic: Heterogeneity in COVID- 19 Spread Patterns and Human Mobility Characteristics across US Counties”. 101st Annual Meeting of the Transportation Research Board (TRB).

published journal article

Building ages and urban growth

Regional Science and Urban Economics

Publication Date

May 1, 1982

Author(s)

Suggested Citation
Jan K. Brueckner (1982) “Building ages and urban growth”, Regional Science and Urban Economics, 12(2), pp. 197–210. Available at: 10.1016/0166-0462(82)90032-1.

policy brief

Performance Analysis and Control Design for On-ramp Metering of Active Merging Bottlenecks

Abstract

Design the control parameters for pre-timed and trafficresponsive on-ramp metering of congested merging bottlenecks.

Suggested Citation
Wenlong Jin (2016) Performance Analysis and Control Design for On-ramp Metering of Active Merging Bottlenecks. Policy Brief. Institute of Transportation Studies, Irvine. Available at: https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/research-results/task2808-rrs-10-16-a11y.pdf.

published journal article

A Comprehensive Study of Bug-Fix Patterns in Autonomous Driving Systems

Proceedings of the ACM on Software Engineering

Publication Date

June 19, 2025

Author(s)

Yuntianyi Chen, Yuqi Huai, Yirui He, Shilong Li, Changnam Hong, Qi Alfred Chen, Joshua Garcia

Abstract

As autonomous driving systems (ADSes) become increasingly complex and integral to daily life, the importance of understanding the nature and mitigation of software bugs in these systems has grown correspondingly. Addressing the challenges of software maintenance in autonomous driving systems (e.g., handling real-time system decisions and ensuring safety-critical reliability) is crucial due to the unique combination of real-time decision-making requirements and the high stakes of operational failures in ADSes. The potential of automated tools in this domain is promising, yet there remains a gap in our comprehension of the challenges faced and the strategies employed during manual debugging and repair of such systems. In this paper, we present an empirical study that investigates bug-fix patterns in ADSes, with the aim of improving reliability and safety. We have analyzed the commit histories and bug reports of two major autonomous driving projects, Apollo and Autoware, from 1,331 bug fixes with the study of bug symptoms, root causes, and bug-fix patterns. Our study reveals several dominant bug-fix patterns, including those related to path planning, data flow, and configuration management. Additionally, we find that the frequency distribution of bug-fix patterns varies significantly depending on their nature and types and that certain categories of bugs are recurrent and more challenging to exterminate. Based on our findings, we propose a hierarchy of ADS bugs and two taxonomies of 15 syntactic bug-fix patterns and 27 semantic bug-fix patterns that offer guidance for bug identification and resolution. We also contribute a benchmark of 1,331 ADS bug-fix instances.

Suggested Citation
Yuntianyi Chen, Yuqi Huai, Yirui He, Shilong Li, Changnam Hong, Qi Alfred Chen and Joshua Garcia (2025) “A Comprehensive Study of Bug-Fix Patterns in Autonomous Driving Systems”, Proceedings of the ACM on Software Engineering, 2(FSE), pp. 380–402. Available at: 10.1145/3715733.

Phd Dissertation

Modeling Disruptions to Roadway Network Bridges, Restoration Workforce, and Vehicle-carried Information Flow for Infrastructure Management

Publication Date

January 1, 2018

Associated Project

Author(s)

Abstract

The ability to model the disruptions of adverse events on various systems, such as infrastructural and social, is an important tool to assessing these systems’ resilience. While previous research on system resilience concentrated on physical infrastructure such as transportation systems, two recent research topics include social resilience and dependencies across many infrastructure systems. For example, transportation is dependent on such systems as power, communications, and the workforces that are key to restoring these infrastructure systems. This dissertation contains three disruption modeling studies that have followed the evolution of resilience research over the past decade from physical systems to interrelated topics. The first study uses mesoscopic traffic simulation to evaluate seismic risk of potential travel time increases from earthquake damage to bridges in a roadway network. This analysis successfully obtained system risk curves of network-wide travel time increases. The second study shifts focus towards workforces that participate in restoring infrastructure systems. It identifies transportation and communications workers and calculates these workers’ exposure to the Peak Ground Accelerations (PGAs) of a 7.8 magnitude Southern California scenario earthquake. Indeed, for this scenario, transportation workers are exposed to statistically significant higher PGAs than non-transportation workers, and communication workers to significantly lower PGAs. The third study proposes a model for the travel time of information along communication-equipped vehicles physically traveling in a network. Vehicles are sampled as equipped vehicles, then their trajectories are analyzed to (1) estimate equipped vehicle link flow and turning movement counts and (2) estimate the frequency of equipped vehicles encountering each other on links and at nodes. This study compares two scenarios: the baseline scenario and a work zone scenario that corresponds to a bridge being damaged in the network. It is hypothesized that there would arise a difference in expected path travel times when (1) the representation of a specified subpath within the sample is increased and (2) when vehicles are routed along currently unused subpaths. This dissertation concludes with a discussion of the contributions of all three studies, as well as suggestions for future work.

Suggested Citation
Pierre Milton C. Auza (2018) Modeling Disruptions to Roadway Network Bridges, Restoration Workforce, and Vehicle-carried Information Flow for Infrastructure Management. Ph.D.. UC Irvine. Available at: https://escholarship.org/uc/item/2vr0j24c (Accessed: October 12, 2023).

published journal article

Evaluating the impact of spatio-temporal demand forecast aggregation on the operational performance of shared autonomous mobility fleets

Transportation

Publication Date

May 1, 2019

Author(s)

Florian Dandl, Michael Hyland, Klaus Bogenberger, Hani Mahmassani
Suggested Citation
Florian Dandl, Michael Hyland, Klaus Bogenberger and Hani S. Mahmassani (2019) “Evaluating the impact of spatio-temporal demand forecast aggregation on the operational performance of shared autonomous mobility fleets”, Transportation, 46(6), pp. 1975–1996. Available at: 10.1007/s11116-019-10007-9.

working paper

Companionship and Altruism in Daily Activity Time Allocation and Travel by Men and Women in the Same Households

Publication Date

January 1, 2007

Author(s)

Konstadinos Goulias

Abstract

In this paper, using data from 366 households we study human interaction within and outside the household. In the analysis altruism and companionship between men and women are explored using path analysis to identify gender-roles and mutual influences. Men and women have very different templates of time allocation characterized by lack of symmetry in relationships between men and women. Although women’s time allocation has some influence on men’s time allocation, it may function as a constraint only when women engage in activities for a considerable amount of time in a day. In contrast, men’s influence is significant and substantial at any level of time allocation. Regarding the relationship between altruism and companionship, men appear to be “rationing” their time and allocate time either to relatives or to others. Women appear to be more fully engaged with relatives and with others (presumably functioning as the social network hubs of the household). Finally, travel is not emerging as a cause but as an outcome supporting once again the practice in activity-based models of considering travel demand as derived from the need to participate in activities. It should also be noted that travel is a very small fraction of the total daily time allocation and does not function as a constraint in budgeting time for activities with and for relatives and other persons. A clear hierarchy also emerges from the path model developed here with blocks of variables determining other blocks of variables in a sequence.