conference paper

Public Transit Use in Pandemic Year 2022: Which Groups Changed Usage?

Proceedings, 104th Annual Meeting of the Transportation Research Board

Publication Date

January 1, 2025

Abstract

The outbreak of the COVID-19 pandemic and its subsequent travel restrictions imposed significant impacts on many aspects of our lives and infrastructures, including an unprecedented decrease in public transit service and ridership. Little is known about specific changes in transit use during the pandemic compared to before using national-level data. In this context, we characterized transit users who changed their public transit use and identified the underlying socio-demographics, location, and trip characteristics that affect these changes using data from the recently published 2022 National Household Travel Survey (NHTS). A logistic regression model developed suggests that those with a higher tendency to reduce transit use after the pandemic were females, unemployed, highly educated, teleworkers, driving license holders, couples without children, those forced to reduce travel due to conditions or disability, and those living in denser areas. In addition, users from low-income households showed greater reductions in transit use than those from high-income families. Transit agencies and planning organizations can use the findings of this study to identify transit users based on revealed changes in transit use after the pandemic to formulate appropriate operational and management strategies to address emerging public transit needs.

Suggested Citation
Rezwana Rafiq and Michael G. McNally (2025) “Public Transit Use in Pandemic Year 2022: Which Groups Changed Usage?”, in Proceedings, 104th Annual Meeting of the Transportation Research Board. Washington, D.C..

MS Thesis

Impacts of Accidents on the Analysis of Measures to Reduce Vehicular Emissions

Publication Date

January 1, 2015

Author(s)

Abstract

The Long Beach Freeway Corridor Improvement Project was started to address concerns regarding increasing air pollutant emissions and traffic congestion, which are partly due to increases in truck volumes and high accident rates. In addition to these efforts, a non-profit organization called PierPass was created in 2005 by the marine terminal operators at the ports of Los Angeles and Long Beach. The PierPass program aimed to alleviate congestion, security and air quality issues experienced by the ports and freeways by incentivizing freight movements during off-peak hours. This paper explores whether it is important to model accidents when analyzing the environmental benefits of policies designed to reduce air pollution from trucks with an application to PierPass. A microscopic traffic simulation model of the freeway network containing the I-710 freeway was utilized to simulate truck accidents under uniquely identified scenarios based on frequent conditions. Then, vehicular emissions for seven common air pollutants were calculated and compared to a no-accident scenario to quantify the effects of accidents on pollutant emission. Results showed that the introduction of incidents slightly increased the average vehicular speeds and slightly decreased the total amount of emissions; however, the effect of incidents may be more pronounced on a network that is not already known to be heavily congested.

Suggested Citation
Karen Sujata (2015) Impacts of Accidents on the Analysis of Measures to Reduce Vehicular Emissions. MS Thesis. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991022552269704701.

MS Thesis

Applying Smart Grid technologies to the secondary distribution system / by Renee Gail Cinar.

Publication Date

January 1, 2014

Author(s)

Abstract

Today’s aging electric delivery infrastructure is undergoing an extreme makeover. The current system has inefficiencies, is congested and unable to meet future power reliability, quality, sustainability (e.g., more renewable power) and security needs. The massive effort to modernize the nation’s electricity delivery system is collectively known as the “Smart Grid.” Transition to a smarter grid will occur over time. This research addresses one area of electric power system modernization, namely the impacts that high penetrations of distributed energy resources (DER), such as solar and batteries, and plug-in electric vehicles (PEVs) could have on the distribution system by (1) evaluating the effect of introducing large amounts of DER and PEV charging on a secondary distribution circuit and (2) developing, applying and evaluating smart grid management scenarios which can reduce consumer electricity costs and flatten residential load profiles. The improved load profiles presented herein demonstrate that traditional residential load profiles can be purposefully reshaped when rooftop solar, energy storage, and plug-in electric vehicles are introduced into the circuit. Through various battery charging and discharging scenarios and controlled electric vehicle charging, residential loads can be reduced to almost zero, flattened, or behave as a distributed generator. By allowing excess solar generation to flow back onto the grid or dispatching batteries during peak load times, the load profile of an individual home or secondary distribution transformer can be altered in a manner that benefits the distribution grid.

Suggested Citation
Renee Gail Cinar (2014) Applying Smart Grid technologies to the secondary distribution system / by Renee Gail Cinar.. MS Thesis. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/u4evf/cdi_proquest_journals_1640768890.

Phd Dissertation

Essays on the competitive dynamics of innovation and product quality / Michael Stefan Mills.

Publication Date

January 1, 2014

Author(s)

Abstract

Firms compete through means other than pricing and advertising. In particular, firms compete through manipulating the quality of their products. In the pharmaceutical industry, firms compete by innovating to create a better quality medicine. The first chapter examines pharmaceutical firms’ strategic response to innovate. The comparison of words used in job advertisements to words used in the International Classification of Diseases are analyzed to measure the amount of innovative activity a firm conducts in a given disease category. From this novel dataset, the results indicate that a firm increases its innovative activity due to its competitors’ increase in innovative action. The second chapter extends a model with vertically differentiated products to include a “brand” firm’s incentive to market a medium quality product (pseudo-generic) to compete with their original high quality product and a competitor’s low quality product. Under certain assumptions of consumer heterogeneity, an incumbent firm will market a pseudo-generic only when it can deter the entry of multiple competitors. The third chapter looks at quality competition in the airline industry by analyzing the changes in the total flight frequency for a city-pair due to the merger of two airlines. The results suggest that a merger can decrease flight frequency by as much as 97 flights per month on some routes. The decreases in flight frequency are almost entirely due to the merger removing a competitor (one of the merging partners) from the route. Consequently, the total change in frequency on most routes is less severe or insignificant all together

Suggested Citation
Michael Stefan Mills (2014) Essays on the competitive dynamics of innovation and product quality / Michael Stefan Mills.. PhD Dissertation. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991001203329704701.

policy brief

The Missing Link in Automated Vehicle Safety: Projected Braking and Realistic Driving Behavior

Abstract

As more automated vehicles (AVs) gradually appear on our roads, they must be able to safely interact with human drivers as well as existing infrastructure designed with human drivers in mind. Current car-following computer models—which determine how AVs adjust their speed and position relative to other vehicles—often struggle to replicate human driving patterns. This deficiency could lead to unpredictable AV behavior, potentially increasing crash risks, disrupting traffic flow, and creating problems at traffic lights and intersections designed for human drivers. If AVs brake much earlier or later than humans, drivers may be caught in ‘dilemma zones’ — unable to safely stop or proceed through the intersection. To address these challenges, the research team conducted a comprehensive analysis of existing car-following models and developed a novel multi-phase projection-based model that ensures safety while exhibiting human-like driving characteristics.

Suggested Citation
Wen-Long Jin (2025) The Missing Link in Automated Vehicle Safety: Projected Braking and Realistic Driving Behavior. Policy Brief UC-ITS-2022-39. UC ITS / ITS-Irvine. Available at: https://doi.org/10.7922/g2j101j6 (Accessed: November 3, 2025).

MS Thesis

The Political Process of Regional Transportation Finance: A study of regional coordination in the polycentric and politically fragmented San Francisco Bay Area

Publication Date

January 1, 2011

Author(s)

Abstract

Over the last 20 years, transportation finance in California has become increasingly balkanized. State and federal gas tax rates have not kept up with inflation, and, increasingly, counties have raised their own sales taxes to improve local transportation facilities, resulting in more county-level decisions and less regional coordination. Yet current literature indicates that regional transportation planning is a necessary element in reducing VMT and our carbon footprint. Looking at a unique instance where the 26 transit operator San Francisco Bay Area was able to develop a single transportation financing plan funded by a $1 increase in bridge tolls, this paper seeks to learn how a regional funding proposal can happen in a polycentric and politically fragmented region such as the Bay Area. Using a combination of interviews and archival research, this paper discusses the multi-stage process through which the proposal passed; makes conclusions as to what was necessary for its success; and makes recommendations as to how feasible it would be for other regions to consider similar regional funding methods. It expands the concept of the political entrepreneur to the multi-state process of passing a regional transportation finance measure, and concludes that the current county sales tax law is not sufficient to accommodate regional transportation funding proposals, without direct legislative approval and the strong initiative of an entrepreneur. Absent a change in state law, regional measures are likely to be infrequent—dependent on a political entrepreneur to take the initiative needed to pass them.

Suggested Citation
David Philip Weinreich (2011) The Political Process of Regional Transportation Finance: A study of regional coordination in the polycentric and politically fragmented San Francisco Bay Area. MA Thesis. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/u4evf/cdi_proquest_journals_874289517.

MS Thesis

Study of the impacts of variable speed limits on travel time, fuel consumption and emissions in a lane drop scenario / by Alejandro Bayas Fernández.

Publication Date

January 1, 2009
Suggested Citation
Alejandro. Bayas Fernández (2009) Study of the impacts of variable speed limits on travel time, fuel consumption and emissions in a lane drop scenario / by Alejandro Bayas Fernández.. MS Thesis. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991023601869704701.

Phd Dissertation

An Empirical Study of Alternative Fuel Vehicle Choice by Commercial Fleets: Lessons in Transportation Choices, and Public Agencies' Organization

Abstract

The concern about air pollution has led government agencies to design and implement mandates to replace some commercial fleets’ gasoline vehicles with Alternative Fuel Vehicles (AFVs). In Part One of this dissertation, I investigate the diffusion of AFV’s in the commercial sector. Commercial fleets are frequently the first target of government regulation because policy agencies can target a large number of vehicles while regulating fewer establishments relative to the household sector. Using stated preference survey data from over 2000 commercial and local government fleets in California, I estimate multinomial logit and nested logit models of fuel choice that predict the probability of choosing each type of AFV. Given certain assumptions about vehicle technology, these models predict that starting in year 2010, almost 17% of new vehicle purchases by the commercial and local government fleets will be electric, about 20% will be compressed natural gas, and almost 21% will be methanol vehicles. I find that fuel choice probabilities differ depending on the market structure. Public agencies seem to be more AFV friendly than private firms. Important factors in fleet vehicle choice are the degree of familiarity of the firm’s staff with the AFV operation, the size of the establishment, government regulations, and the availability of the refueling infrastructure. In Part Two, I review hypotheses about the determinants of local government agencies’ efficiency and use the stated preference survey data to test these hypotheses. Public choice models predict systematic differences among government agencies regarding their cost considerations and sensitivity to environmental issues. The empirical evidence identifies two factors that affect government agencies’ performance. The first factor is jurisdiction: an agency that has a more rigid boundary, such as a city or a county, seems to operate more efficiently than an agency that has more flexible geographic boundaries, as is the case with the special districts. The second factor is direct citizen voting: an agency director who is subject to re-election seems to coordinate a more efficient agency operation than one that is appointed to the job as a career position.

Suggested Citation
Soheila Crane (1996) An Empirical Study of Alternative Fuel Vehicle Choice by Commercial Fleets: Lessons in Transportation Choices, and Public Agencies' Organization. PhD Dissertation. UC Irvine. Available at: https://escholarship.org/uc/item/8pt2j499.

conference paper

Freight transportation contracting under uncertainty

Proceedings of the 88th annual meeting of the transportation research board

Publication Date

January 1, 2009

Abstract

Uncertainties in transportation capacity and costs pose a significant challenge for both shippers and carriers in the trucking industry. One way to hedge these uncertainties is to use concepts from the theory of Real Options to craft derivative contracts, which the authors call truckload options in this paper. In its simplest form, a truckload call (put) option gives its holder the right to buy (sell) truckload services on a specific route, at a predetermined price on a predetermined date. The holder decides if a truckload option should be exercised depending on information available when the option expires. Truckload options are not yet available, however, so the purpose of this paper is to develop a truckload options pricing model and to show the usefulness of truckload options to both shippers and carriers. Since the price of a truckload option depends on the spot price of a truckload, the authors first model the dynamics of spot rates using a common stochastic process. Unlike financial markets where high frequency data are available, spot prices for trucking services are not public and the authors can only observe some monthly statistics. This complicates slightly the estimation of necessary parameters, which the authors obtain via two independent methods (variogram analysis and maximum likelihood), before developing a truckload options pricing formula. A numerical example based on real data shows that truckload options would be quite valuable to the trucking industry.

Suggested Citation
Mei-Ting Tsai, Jean-Daniel Saphores and Amelia Regan (2009) “Freight transportation contracting under uncertainty”, in Proceedings of the 88th annual meeting of the transportation research board, p. 14p.