policy brief

Shared Autonomous Mobility Services Show Promise for Increasing Access to Employment in Southern California

Abstract

Workers in Southern California currently face transportation related challenges accessing employment opportunities, including but not limited to high parking costs and/or limited parking availability in dense employment and residential areas; long commute distances between residential areas and employment opportunities; and poor transit service quality in many areas. These challenges are particularly burdensome for low-income households that may not have access to a personal vehicle and/or live in job-poor neighborhoods, as having a personal vehicle may be the only viable way to get to work.

research report

Assessment of the Employment Accessibility Benefits of Shared Autonomous Mobility Services

Abstract

The goal of this study is to assess and quantify the potential employment accessibility benefits of Shared Autonomous Mobility Service (SAMS) commute modes across a large diverse metropolitan region considering heterogeneity in the working population. To meet this goal, this study employs a welfare-based (i.e. log sum-based) measure of accessibility, obtained via estimating a hierarchical work destination-commute mode choice model. The employment accessibility log sum measure incorporates the spatial distribution of worker residences and employment opportunities, the attributes of the available commute modes, and the characteristics of individual workers. This research further captures the heterogeneity of workers using latent class analysis (LCA). The latent class analysis model inputs include the socio-demographic characteristics of workers to subsequently account for different worker clusters valuing different types of employment opportunities differently. The accessibility analysis results indicate: (i) the accessibility benefit differences across latent classes are modest but young workers and low-income workers do see higher benefits than high- and middle-income workers; (ii) there are substantial spatial differences in accessibility benefits with workers living in lower density areas benefiting more than workers living in high-density areas; (iii) nearly all the accessibility benefits come from the SAMS-only mode as opposed to the SAMS+Transit mode; and (iv) the SAMS cost per mile assumption significantly impacts the magnitude of the overall employment accessibility benefits.

policy brief

A Review of Reduced and Free Transit Fare Programs in California

Abstract

Free or reduced-fare transit passes have the potential to increase transit ridership, enhance the mobility of underserved groups (e.g., low-income, seniors, and youth), and reduce the environmental footprint of transportation. Under the right conditions, these programs can also help reduce traffic congestion and motor vehicle use. Transit agencies in different parts of the world have been experimenting with free or reduced-fare transit for decades, yet there are still substantial concerns about the impacts of free or reduced-fare transit on ridership as well as on the fiscal health of transit agencies. Some of these concerns linger partly because rigorous academic studies on free and reduced-fare transit passes are still rare.

Phd Dissertation

Impacts of electric highways for heavy-duty trucks

Abstract

The incorporation of alternative fuel vehicles has been essential in reducing emissions in the transportation sector. Particularly to heavy-duty trucks, zero-emission technologies are becoming more attractive. However, batteries and fuel cells still face a long way until they became a viable solution in terms of price, autonomy, weight, and infrastructure. An interim solution is the use of an overhead catenary system, also known as eHighway. The pilot project demonstrated the feasibility of the eHighway system; however, the literature exploring this type of technology is lacking. This dissertation aims to cover this literature gap and propose a new framework to comprehensively explore the aspects of an eHighway implementation in terms of optimal placement, effects on the well-to-wheel (WTW) emissions, and impacts on the power grid. This methodology was applied to a California model using data from the California Statewide Freight Forecasting Model. First, we defined the optimal eHighway placement to maximize vehicle miles traveled in the system or minimize emissions around disadvantage communities in four different scenarios for the years of 2020 and 2040. This process shows that most eHighways would be located along the I-5 or close to ports to maximize vehicle miles traveled or in Central Valley to maximize the benefit for disadvantage communities. Second, we estimated the WTW emissions for heavy-duty trucks according to the truck’s fuel type for each of the scenarios with adoption rates from 25% to 100%. The total emissions in terms of CO2 and NOx were compared to a scenario without eHighway. All the eHighway scenarios for 2020 and 2040 reduced the total WTW heavy-duty truck emissions. The best-case scenario for 2020, with 500 miles of total eHighway length and adoption rate of 100%, reached a reduction of almost 8% in CO2 emission and over 20% of NOx. The same scenario showed a reduction of 16% in CO2 and 20% of NOx for the year 2040. Finally, we analyzed the impacts of the eHighway energy demand on the state’s power grid. We showed that some of the systems would require up to 1 MWh of daily energy from some power substations. However, due to the unavailability of public data on California’s power grid, we could not draw conclusions in terms of the ability of these substations to handle such demands. These results show the applicability of the proposed methodology for the deployment and impacts of the eHighway system. Furthermore, although there are other aspects to be considered before large-scale implementation of the eHighway system (e.g., costs), the results presented in this study support the deployment of an eHighway system in California to support the urgent need for making road freight transport more sustainable. 

policy brief

Travel Varies Greatly Between Voluntary Versus Involuntary Carless Households in California

Abstract

In spite of the critical importance of mobility for quality of life and economic well-being, the travel behavior of households without motor vehicles has received insufficient attention even though “carlessness” may bethe most vivid expression of mobility disadvantage in our car-centric society. Approximately 10.6 million (9 %) of U.S. households do not own a motor vehicle (car, pickup, van, SUV, or motorbike), including over one million in California. These “carless” households form two groups: (1) involuntarily carless households who are forced to live without cars, and (2) voluntarily carless households who chose to do so. Since one of the strategic goals of federal transportation policy is “to increase transportation choices and access to transportation services for all” it is essential to understand the travel behavior of households who are unable to own a motor vehicle. Indeed, many involuntarily carless households are experiencing economic hardship, disabilities, racial and age discrimination, or cultural barriers. Understanding the travel pattern of voluntarily carless households is also necessary to formulate policies aimed at decreasing vehicle use. Reducing personal vehicle use would help relieve congestion, decrease road accidents, improve air quality, cut emissions of greenhouse gases, and improve the health of people who switch to more active modes, such as walking and biking.

research report

A Review of Reduced and Free Transit Fare Programs in California

Abstract

To gain a better understanding of the current use and performance of free and reduced-fare transit pass programs, researchers at UC Irvine surveyed California transit agencies with a focus on members of the California Transit Association (CTA) during November and December 2019. Fifty-nine agencies, representing a broad cross-section of California transit operators, responded. Three-quarters of respondents offered one or more free or reduced-fare transit pass programs in fiscal year 2018-19. While most respondents stated that free or reduced-fare transit passes increase ridership, many had concerns about the effect on their agency’s farebox recovery ratio, and to some extent on the fiscal health of their agency, though almost half of the respondents did not know the actual impacts. Those agencies offering student pass programs funded by student fees or employee programs funded by employers did not report any negative impact on ridership or on farebox recovery ratios. This confirms that free or reduced-fare transit pass programs structured like insurance programs (where a large group of potential transit riders—such as all students at a college or all employees in a large firm—periodically pays a lump sum to a transit agency while only a subset of that group actually uses transit) can be good for both riders and transit agencies. Free or reduced fare pass programs have an important role to play in transportation policy in California, but we should not ask too much for these programs. To achieve their full potential, they should be integrated into comprehensive policies to achieve California’s social and environmental goals.

policy brief

General Plan Content Related to Transportation and Land Use Varies Significantly Across Cities in Orange County

Abstract

California cities and counties are required to prepare general plans, which serve as long-range planning documents for future growth. General plans do not necessarily focus on a specific investment project or regulatory action that shapes development patterns directly but rather play an important role in informing stakeholders (e.g., landowners, developers, planners, elected officials) and supporting their decision making. The state provides guidelines and requirements for general plans. However, the content and structure of general plans vary markedly across cities. Some cities simply list goals and policies, while other cities provide detailed information using various forms of written and visual presentation. An increasing number of studies have examined to what extent plans are implemented and under what circumstances they are implemented successfully. However, little is known about the informational content of general plans and how the structural characteristics of general plans can either facilitate or hinder the use of the plan itself.

Phd Dissertation

Interactions between knowledge and practitioner communities: engagement to enhance urban social-ecological resilience

Abstract

My research focuses on the processes through which partners interact to integrate and cultivate nature in cities in order to promote healthy communities and social-ecological systems. This scholarship is timely and important given the scale of environmental change humans living in cities are driving globally. Cities both contribute to and experience changes such as increased flooding and higher temperatures, with vulnerable populations bearing the brunt of these impacts, while also having less access to the benefits that nature can provide. Cities are also highly networked places with the potential to be leaders in piloting and leveraging solutions to the world’s most pressing social-ecological challenges. Utilizing an interpretive methodology, I spent one year with a university center for urban resilience in Los Angeles, attending meetings and carrying out over 40 semi-structured interviews conducted with practitioner and knowledge community participants in the region. My dissertation explains how universities navigate their relationships with partners focusing on legitimacy, inclusion and the fluidity between the two concepts. Recommendations are provided on how to bridge legitimacy and inclusion to strategically benefit policy and planning partnership efforts. This dissertation also shows how partner narratives of urban nature are dynamic, shifting over time and diverse across space and groups. Recommendations are provided on how narratives can be a tool to better understand partner perspectives, identify synergies and divergences among narratives, and develop more inclusive policy and planning processes. This dissertation also evaluates a university led urban environmental stewardship mapping and assessment project (LA STEW-MAP), including better understanding practitioner perspectives. Recommendations are provided on how the LA STEW-MAP process can be improved to operationalize a social-ecological systems approach and as a community engagement tool.

policy brief

Electrified Buses Provide Life Cycle Environmental Benefits but Need Cost Reductions and Policy Support for Near-Term Adoption

Abstract

In December 2018, the California Air Resources Board (CARB) approved the Innovative Clean Transit regulation, which is designed to transition the state to all-electric bus fleets by 2040. To comply with this first-of its-kind regulation, transit agencies have two alternatives: battery electric buses (BEBs) and hydrogen fuel cell electric buses (FCEBs). These options vary in energy requirements, overall effectiveness in reducing different emission types, associated life cycle costs (including disposal of the bus), and ability to meet operating needs of transit agencies. To support transit agencies and decision makers transition to cleaner bus technologies, researchers at UC Irvine developed a life cycle-based analysis (LCA) tool to estimate the potential costs and benefits of switching to BEBs and FCEBs compared to conventional buses. The LCA tool was tested on the Orange County Transportation Authority (OCTA) to better understand the environmental impacts and cost constraints.

Phd Dissertation

Analysis of complex travel behavior a tour-based approach

Publication Date

November 21, 2019

Author(s)

Abstract

Complex travel behavior places travel in a broader context than in the conventional trip-based approach. The activity-based approach provides an analysis framework that positions travel decisions as dependent on a collection of activities that form an agenda for participation and, therefore, cannot be properly analyzed on individual trip basis. The basic units of analysis for activity-based approaches are tours, which can be defined as sequences of trips and activities that begin and end at the same location. In this dissertation, I apply a tour-based approach to analyze complex travel behavior from three perspectives: sustainability, technology, and economics. First, I examine the complex travel behavior of workers, who utilize a sustainable transport option, namely public transit. I identify dominant patterns of work tours and analyze factors affecting tour choice using Structural Equation Modeling (SEM). The results obtained by using the 2017 National Household Travel Survey dataset suggest that 80 percent of work tours consist of seven dominant tours and that tour choice is influenced by a set of socio-demographic, built environment, and activity-travel characteristics. Second, the complex travel behavior of people who use technology-enabled ride-hailing services, such as Uber/Lyft, is explored. In particular, I identify heterogeneous groups of ride-hailing users by using Latent Class Analysis, analyze the activity-travel patterns of each of these groups, and discuss the ramifications of that behavior to policy directives. Lastly, I explore the travel behavior of workers, again in terms of tours, when they are exposed to an economic downturn, the 2007-2009 recession. I apply multi-group SEM to analyze changes in tour choice during the recession (2009) compared to pre- (2006) and post-recession (2012) years. Using American Time Use Survey data, this study shows that activity-travel relationships and their role in tour choices differed significantly in the recession year. The results of this study provide insights into potential changes in worker’s travel demand during a recession, which would contribute to building better pattern choice sets in tour-based models. The common thread throughout this dissertation is the development of a framework for analyzing complex travel behavior under disruptive changes due to environment, technology, and economics forces.