Papers by Giovanni Circella
Transportation Research Record, Jul 2, 2022
The COVID-19 pandemic has caused huge disruption to society with, among other impacts, direct and... more The COVID-19 pandemic has caused huge disruption to society with, among other impacts, direct and indirect effects (e.g. through public health measures) on travel behavior. Since its initial outbreak, COVID-19 has manifested itself into a global pandemic. In response to extensive community spread and potential risk of infection, many state and local governments implemented stay-at-home orders along with measures for social distancing restricting non-essential travel for residents. These travel advisories imposed broad restrictions on millions of Americans resulting in drastic changes in mobility and disruptions to economic activity. In our study we use a combination of data from two previous online surveys and a current data collection conducted to evaluate the impacts of the pandemic on mobility to form a unique longitudinal panel. The use of a longitudinal panel provides us the ability to observe initial trends in travel behavior change, adoption of online shopping, active travel and use of shared mobility services. In our analysis present initial descriptive statistics from the sample to examine the changes in various components of travel behavior in the sample (N=1,274) and for each income/occupation group separately. We find substantial shifts from physical commutes to teleworking, more adoption of eshopping and home delivery services, more frequent trips by walking and biking for leisure purposes, and changes in ride-hailing use. Also, we discuss implications of these findings from the perspectives of environmental sustainability and social equity. This study concludes with suggestions of directions for effective policy and future research.
RePEc: Research Papers in Economics, Apr 1, 2020
Self-driving vehicles, as a revolution in mobility, are emerging and developing rapidly. However,... more Self-driving vehicles, as a revolution in mobility, are emerging and developing rapidly. However, public attitudes toward this new unproven technology are still uncertain. Given the significant influence of attitude toward a new technology on the intention to use it, the question arises as to why some people are in favor of this technology whereas others are not. Additionally, questions about the key attitudes influencing self-driving technology acceptance, where these attitudes come from, and how they interact with each other have not yet been addressed. This study aims to explore these research questions based on data collected from people who live or work in the West Village (WV) area of the University of California, Davis (UCD) campus after a self-driving electric shuttle was piloted in this area. structural equation modeling (SEM) was employed to explore interactions between attitude elements. The results show that affect-i.e., liking or enthusiasm for self-driving shuttles-strongly explains the acceptance of self-driving technology. A higher level of affect could be formed by strengthening an individual's trust. Additionally, trust works as an important mediator between perceived risk, usefulness, and ease of use on both affect and intention to ride self-driving vehicles. Perceived risk captured more security and functional concerns, reflecting uncertainty around current self-driving technology. The model identified important bi-directional influences between trust and affect. Significant effects of mental and physical intangibility were also shown, but each works differently on cognitive beliefs. Individuals' socio-demographic, lifestyle, and mobility characteristics also exert influences on attitude and self-driving technology acceptance.
RePEc: Research Papers in Economics, 2019
RePEc: Research Papers in Economics, Jul 1, 2021
Autonomous Vehicles Measure
Does Travel-based Multitasking Influence Commute Mode Choice? An Investigation of Northern California Commuters
Changes in activity organization and travel behavior choices in the United States
Transportation Amid Pandemics
Transportation Research Record: Journal of the Transportation Research Board
The COVID-19 pandemic has caused a huge disruption worldwide with direct and indirect effects on ... more The COVID-19 pandemic has caused a huge disruption worldwide with direct and indirect effects on travel behavior. In response to extensive community spread and potential risk of infection, during the early stage of the pandemic many state and local governments implemented non-pharmaceutical interventions that restricted non-essential travel for residents. This study evaluates the impacts of the pandemic on mobility by analyzing micro panel data ( N = 1,274) collected in the United States via online surveys in two periods, before and during the early phase of the pandemic. The panel makes it possible to observe initial trends in travel behavior change, adoption of online shopping, active travel, and use of shared mobility services. This analysis intends to document a high-level overview of the initial impacts to spur future research to dive deeper into these topics. With the analysis of the panel data, substantial shifts are found from physical commutes to teleworking, more adoption ...
Analysis of the Georgia Add-On to the 2016–2017 National Household Travel Survey
Georgia. Department of Transportation. Office of Performance-Based Management & Research, Aug 1, 2021
Investigating Demographic and Multitasking Sources of Systematic Heterogeneity with Respect to the Impact of Travel Time on Commute Mode Choice
Transportation Research Board 98th Annual MeetingTransportation Research Board, 2019
BeltLine Bicyclist Facility Preferences and Effects on Increasing Trips
Georgia. Department of Transportation. Office of Performance-Based Management & Research, Mar 1, 2019
2019Final, Dec 2016 \\u2013 April 2019PDFTech ReportFHWA-GA-19-1638PI#: 0015304Before and after s... more 2019Final, Dec 2016 \\u2013 April 2019PDFTech ReportFHWA-GA-19-1638PI#: 0015304Before and after studiesBicycle facilitiesBicycle travelComfortConsumer preferencesSafetyBicycle infrastructureAtlanta BeltLineMultiuse TrailProtected Bicycle LanesQuasi-experimental DesignPanel SurveyUnited StatesGeorgiaGeorgia. Department of Transportation. Office of Performance-Based Management & ResearchWatkins, Kari E.Circella, GiovanniMokhtarian, Patricia L.Clark, CalvinPassmore, ReidGeorgia Institute of Technology. School of Civil and Environmental EngineeringGeorgia. Department of Transportation. Office of ResearchUS Transportation CollectionThe objectives of this study were to investigate perceptions of users and potential users of bicycle infrastructure and to investigate the impact of multi-use paths on bicycle trips. Data were collected through a before-and-after survey in 2017 and 2018 (wave 1 N=1,335, wave 2 N=713) of residents near the Eastside Atlanta BeltLine extension and the Westside Atlanta BeltLine trail, along with residents in neighboring control communities of Grant Park and South Atlanta. Survey data was analyzed using statistical models such as analysis of variance, ordinary least squared regression, and segmented models. The analyses indicate positive perceptions of comfort and safety along with willingness to try biking on facilities with a greater degree of separation from traffic. Although results suggest that those residing near the BeltLine projects perceived a greater degree of neighborhood improvements for both biking and walking, there does not appear to be any statistically significant difference between the BeltLine and control communities in terms of actual changes in frequency of bicycling. The findings of this research suggest that although the BeltLine has had a positive impact on perceptions of the bikeability of the neighborhood it is not enough to spur substantial changes in behavior.78
The Impact of Emerging Technologies and Trends on Travel Demand in Georgia
Georgia Institute of Technology, Oct 1, 2019
2019PDFTech ReportKim, Sung HooMokhtarian, Patricia L.Circella, GiovanniGeorgia Tech Research Cor... more 2019PDFTech ReportKim, Sung HooMokhtarian, Patricia L.Circella, GiovanniGeorgia Tech Research CorporationGeorgia Institute of Technology, Office of Performance-Based Management and ResearchGeorgia. Department of Transportation. Office of Performance-Based Management & ResearchUnited States. Department of Transportation. University Transportation Centers (UTC) ProgramUnited States. Department of Transportation. Federal Highway AdministrationGeorgia Institute of TechnologyGeorgiaUnited StatesImpactsTechnological innovationsTravel demandAttitudesAutonomous vehiclesRidesharingTelecommutingTransportation planningTravel behaviorCar ownership (Railroads)FHWA-GA-19-16310015283, 69A3551747116.FinalThis study aims to enhance understanding of the impact of new and emerging technologies on travel behavior/demand for the state of Georgia, and, thus, potentially contribute to improving transportation planning and demand forecasting for Georgia residents. In this project, the research team designed and implemented a wide-ranging travel survey that explores people\u2019s opinions about travel-related issues, together with how they use new mobility technologies and services, and travel in general. The study employed two sampling frames: (1) address-based stratified randomly sampled households, and (2) Georgia residents who participated in the 2017 National Household Travel Survey (NHTS) and agreed to be contacted for further surveys. The data were collected across about six months. The study explores five main themes: general travel behaviors, commute and work patterns, general opinions and attitudes, new and emerging technologies and services, and future transportation, with a specific focus on autonomous vehicles. Some findings include: despite the low levels of current ownership of alternative-fuel vehicles (2.2% of primary vehicles are hybrid/electric), respondents exhibit considerable interest in having such vehicles (59%); more than 5% \u201ccommute\u201d by working at home, compared to 3% who use transit; overall, ridehailing services seem to have more substitution effects than complementarity and generation effects, including both car-for-car substitution and net reductions in the use of active transportation and public transit modes; and half of respondents (51%) said they are likely or very likely to own a self-driving car, whereas 27% and 12% are likely or very likely to use a driverless taxi alone/with others and with strangers, respectively. Based on results, the study provides some policy implications.112
What Affects Millennials’ Mobility? Part I: Investigating the Environmental Concerns, Lifestyles, Mobility-Related Attitudes and Adoption of Technology of Young Adults in California
Recent research has highlighted significant modifications in travel demand, suggesting a “VMT Pea... more Recent research has highlighted significant modifications in travel demand, suggesting a “VMT Peak”, and a peak in car ownership among young adults in California and the rest of the United States. In order to investigate this topic, and the motivations behind these trends, this study will undertake a detailed investigation of travel behavior and the propensity to purchase a car among young adults (aged 18-30) in California. Through the assistance of a commercial vendor, the authors will develop a representative sample of the population of young adults in California, and administer an online survey developed as part of the project. The research will explore the impact of a range of factors, including personal attitudes and preferences (e.g. about travel, the adoption of technology, the adoption of alternative-fuel vehicles, social, economic and environmental issues), lifestyles, the urban form, the individual’s living arrangements, the influence of peers and online social networks. T...
Research Papers in Economics, 2021
Author(s): Matson, Grant; McElroy, Sean; Circella, Giovanni; Lee, Yongsung | Abstract: The onset ... more Author(s): Matson, Grant; McElroy, Sean; Circella, Giovanni; Lee, Yongsung | Abstract: The onset of the COVID-19 pandemic caused massive travel disruptions across the country.nMany people nationwide shifted to telework following stay-at-home orders, while those providing essential operations and services continued to travel to work. The pandemic’s impacts on travel behavior have complex environmental and equity implications. Telecommuting can be a means of decreasing vehicle miles traveled and greenhouse gas emissions associated with commuter travel and can reduce congestion during peak times. However, not all jobs can be performed from home. Policymakers and regulators who are considering policies to encourage telecommuting to achieve greenhouse gas reduction goals need to consider potential inequities that may arise or be intensified by these policies.Researchers at the University of California, Davis examined the impacts of the COVID-19 pandemic on telecommuting patterns among va...
What Drives the Gap? Decomposing Differences between Millennials and Generation X in Transportation-Related Attitudes
Investigating the Satisfaction with Travel Amounts: A Comparison of Commuters and Non-commuters in California
Does Travel-based Multitasking Influence Commute Mode Choice? An Investigation of Northern California Commuters
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Papers by Giovanni Circella