The Influence of Housing Characteristics on Complex Travel Behavior

Status

In Progress

Project Timeline

January 1, 2020 - December 31, 2020

Principal Investigator

Campus(es)

UC Irvine

Project Summary

UPDATED ABSTRACT: Recent California policy discussions suggest that the travel impacts resulting from strategies for housing growth are not well understood, in part because metropolitan growth has always occurred according to local zoning and land use plans. Fundamental alterations of local planning guidelines, in turn, have unknown transportation impacts. This project reviewed and synthesized policy and academic literature on housing-and-transportation linkages. The project team then applied a process developed in related research to categorize tour-based travel patterns and related these to household characteristics. The project team established connections between household tour behavior and residential variables, which were used to classify types of travelers. The focus of this research was on users of public transit and ride hailing services.

The Causes and Consequences of Local Growth Control: A Transportation Perspective

Status

Complete

Project Timeline

October 8, 2019 - October 7, 2020

Principal Investigator

Campus(es)

UC Irvine

Project Summary

This project will synthesize two sets of studies concerning the causes and consequences of local growth control focusing on implications for transportation and the unique context of each study. The first set of studies addresses the determinants of local growth controls and the circumstances under which a locality is likely to adopt relatively restrictive land use regulations. This body of work includes municipality-level analyses of the determinants of growth control and investigations of voting patterns on growth control measures and relevant issues. The second body of research to be reviewed is related to how limited housing supply (due to growth control and/or other regulatory barriers) affects household residential location and travel patterns. This body of work covers empirical research on the impact of inelastic housing supply on population distribution and resultant transportation outcomes as well as studies on broader transportation challenges that arise due to regulatory barriers to housing development and forces behind them.

Understanding the Impact of Housing Costs in California on Commute Length in Terms of Travel Time and Distance

Status

Complete

Project Timeline

October 6, 2019 - October 5, 2020

Principal Investigator

Campus(es)

UC Irvine

Project Summary

Concerns about the environmental impacts of transportation have turned reducing vehicle-miles traveled (VMT) into a policy priority. One way to decrease VMT is to reduce the length of commuting trips. Unfortunately, the average U.S. commute keeps getting longer. Prior research has investigated the determinants of commuting, but few have analyzed the linkage between housing costs and the length of commuting. This problem is especially salient in California given the state’s perennial housing shortage and the high costs of housing, which have forced many lower- and middle-class households to move inland in search of more affordable housing at the cost of longer commutes. Most of those commuting trips are by car. This project investigates these linkages using Generalized Structural Equation Modeling and analyzing 2012 CHTS data for Los Angeles County – the most populous county in the U.S. The model, which jointly explains commuting distance and time, accounts for residential self-selection and car use endogeneity, while controlling for household characteristics and land use around residences and workplaces. Better understanding the determinants of commuting is critical to inform housing and transportation policy, improve the health of commuters, reduce air pollution, and achieve climate goals.

Accessibility, Affordability, and the Allocation of Housing Targets to California’s Local Governments

Status

Complete

Project Timeline

October 4, 2019 - October 3, 2020

Principal Investigator

Project Team

Campus(es)

UC Irvine

Project Summary

California’s Housing Element law requires the allocation of housing targets to local governments. These targets should align with long-range regional strategies to concentrate growth in transit rich areas, but little evidence exists about the effectiveness of housing allocation schemes for achieving accessibility and affordability. Indeed, there is some evidence that – to date – the law has not served these goals effectively. In 2018 California Senate Bill (SB) 828 significantly amended the Housing Element law, conferring additional authority on the California Department of Housing & Community Development (HCD) to determine housing targets. Moreover, SB 50 (introduced in 2019) proposes to require HCD to identify “jobs-rich” areas, in which local governments would be required to allow relatively dense residential development. SB 50 proposes to also raise the minimum allowable density for residential development in areas close to transit stops. State legislators and administrators have very little information to evaluate the current housing target allocation process or its interaction with the regulatory scheme contemplated by SB 50. This project would fill that gap, providing guidance for linking housing and transportation policy. This project will provide decision support for state legislators and administrators by: 1) comparing California’s housing target allocation and implementation methods to methods currently used in other states, as well as methods described in the scholarly literature; 2) comparing the possible effects of different allocation and implementation methods on job accessibility at different levels of housing affordability; and 3) identifying ways that future legislation and implementation could promote the goals of the Housing Element law related to accessibility.

Spatial Modeling of Future Light- and Heavy-Duty Vehicle Travel and Refueling Patterns in California

Status

Complete

Project Timeline

November 1, 2019 - October 31, 2020

Principal Investigator

Project Summary

There is a strong need to better understand what future fuel demand patterns and infrastructure requirements for zero-emission vehicles (ZEVs) may be in California over the next 20 years. This includes understanding the numbers of vehicles, travel patterns, refueling patterns, refueling station needs, and the implications for the energy system within California. Fuel station location and size decisions will depend on this information, as will planning for electric power, renewable natural gas, and other energy systems.This project will develop a spatial model of light- and heavy-duty vehicle travel in California to explore this issue. The study will start with two existing spatial tools: the ITS-Davis-developed prototype truck travel model, and the natural gas truck demand model. The study will conduct a first order estimation of types of refueling infrastructure locations, and how light- and heavy-duty vehicle infrastructure may or may not be co-located. Concurrently, the study will update and enhance the capabilities of the spatial and demand modeling tools to create a single tool to endogenously project the numbers of vehicles, travel patterns, and locations of refueling infrastructure. The modeling tool could also be used to evaluate geo-fencing strategies, by incorporating emissions-sensitive area information into the model.

Travel Demand Modeling Methodology Recommendations for the Link21 Program

Status

Complete

Project Timeline

June 1, 2019 - May 31, 2020

Principal Investigator

Project Summary

The three revolutions in transportation—shared mobility, electrification and vehicle automation—will fundamentally change the way individuals live, work, socialize, and travel in cities. Travel-related uncertainty and future travel demand are just two key challenges decision-makers face in the decision to build long-term plans for massive transportation projects, such as the proposed second rail crossing in the San Francisco Bay Area (i.e. a second tunnel or bridge dedicated to rail transportation, in addition to the current TransBay BART tunnel), and whether to also include intercity rail in this crossing. This proposed infrastructure will require massive levels of funding and many years to complete, making the exploration of how mobility will change in the meantime critical to assisting in the planning of this proposed infrastructure project. The research team will support the Capitol Corridor Joint Power Authority (CCJPA) with evaluating current travel patterns in the Northern California mega-region, with a focus on the San Francisco Bay Area as an origin and/or destination, including current trip patterns, directionality, mode share, and impacts on traffic congestion. In particular, the researchers will assist the CCJPA with an assessment of the current market for transportation to/from the region, and the extent to which this market is currently served by the existing public transportation options vs. fulfilled by the use of private vehicles on the highway network. The team will review existing documents from planning agencies in the region, future travel demand forecasts, and assessments from other sources (e.g., universities, metropolitan planning organizations, etc.), to collect the available information on current travel patterns and future travel demand in the area, and to identify opportunities and limitations for learning from these document in regard to evaluating future transportation patterns in the Northern California mega-region. The project will inform the CCJPA and decision-makers on current travel patterns in the region of study (baseline conditions), and will inform the use (and limitations to the use) of available approaches and modeling tools to explore future travel patterns—e.g., in a scenario planning approach—as well as related uncertainties in future years when transformative changes via the three transportation revolutions are also in play. Hence, the project will help to make more informed decisions on the expected returns of the proposed infrastructure project—and the eventual inclusion of intercity rail—at a time when the transportation sector is experiencing profound transformation with changing lifestyles and travel patterns due to the introduction of new technologies and mobility services.

Understanding the Relationship Between Aging, Residential Location, and Travel among Different Senior Cohorts

Status

Complete

Project Timeline

July 1, 2019 - June 30, 2020

Principal Investigator

Martin Wachs

Project Summary

California is growing faster and aging more rapidly than America as a whole. California’s population aged 60 years and over is expected to grow more than three times as fast as the total population. Older adults age in place – increasingly in suburban areas where access to transit and pedestrian-friendly neighborhoods is limited. Data from the 2017 National Household Travel Survey show that people over age 65 made 86 percent of their trips by automobile; 66 percent as drivers. As they age, however, many older adults limit their driving and ultimately lose the ability to drive altogether, affecting their quality of life in old age. Prior studies of travel patterns and residential location of the elderly rely on “cross sectional” data from censuses and surveys – comparing different population groups to one another at a single point in time. This limits our understanding of changes in behavior over time because elderly people in coming decades will differ substantially from today’s older population. Older populations in the future will exhibit residential and travel patterns reflecting choices they made when they were younger and may not resemble patterns typical of today’s elderly. Cohorts of adults who will grow old in coming decades, however, are already alive and their behavior can be observed. This study will compare relationships among aging, residential location, and travel among past, current, and soon-to-be elderly people and explore which differences are due to the aging process and which are due to life style differences among cohorts that were established when they were younger. Using the Health and Retirement Survey, a rich data set rarely used to study transportation and travel, the research team will test (1) whether recent cohorts of older adults – those about to enter old age – have greater access to transportation (driving and proximity to transit) than older cohorts (2) the factors associated with driving cessation and moves to transit-rich neighborhoods, and (3) relationships between limited access to transportation and quality-of-life outcome measures (e.g. employment, physical activity, out-of-home activity participation, and life satisfaction). Original methodological contributions will be made along with insights of importance to policymakers who address the needs of our rapidly aging population.

Urban Design at the Intersection of Transportation, Climate Change, Ecology, and Social Justice

Status

In Progress

Project Timeline

August 1, 2019 - June 30, 2020

Principal Investigator

Project Summary

In February 2019, the U.S. Congress announced a resolution for the Green New Deal (GND), a set of policies to drive renewable energy and the low-carbon economy and eradicate poverty while protecting against climate change. Transportation infrastructure was a prominent part of the original 1930s New Deal, including projects such as highways and bridges. Transportation is now a critical part of any broad effort to reduce greenhouse gas (GHG) emissions. To what extent do we understand the potential of the GND to remake the way we move through cities and regions? This project takes on transportation and urban climate futures by focusing on social and ecological questions of transportation infrastructure prompted by the GND and how to design for them. Questions about what to do with infrastructure are caught between rubrics of efficiency, environmental sustainability, and social impact. Given the climate change and social justice imperatives of the GND, how do planners, city managers, and community groups understand and make decisions about long-term, large-cost transportation infrastructure in ways that are environmentally and socially transformative? This research addresses this question by focusing on the intersection of urban design, environmental ethnography, and transportation planning, furthering understanding of contested social and environmental conditions of the present, investigating the possible bounds of desired outcomes of the future.

From Traffic Impact Analysis to Accessibility Impact Analysis: Developing and Testing a Next Generation Development Impact Analysis Tool

Status

Complete

Project Timeline

July 1, 2019 - June 30, 2020

Principal Investigator

Campus(es)

UCLA

Project Summary

For decades evaluation of the benefits and costs of new development or redevelopment in urban areas has centered on the effects of development on nearby traffic flows. To address the traffic flow focus of traffic impact analyses, SB 743 directed the Governor’s Office of Planning and Research (OPR) to develop alternative criteria for measuring the impact of projects. In response, OPR proposed using vehicle miles traveled (VMT) as the most appropriate metric to evaluate a project’s transportation impacts. While most observers agree that a new focus on VMT offers a more holistic picture of transportation impact than focusing on automobile delay as measured by Level of Service (LOS), the new analytical model still centers on adjacent road networks largely distinct from how the proposed development might be expected to benefit cities generally, and agglomerations of activities specifically. A large and growing body of research argues against focusing on mobility (whether to improve the driving experience traditionally or to discourage driving more recently) in favor of focusing on access to destinations when evaluating the role of transportation systems in urban systems. These works by eminent transportation scholars suggest that the move in California from LOS to VMT is a step in the right direction, but not the last step. A more complete and practical accessibility impact analysis tool is needed to better understand the effects of development on urban systems. This research project builds on a series of recent projects and papers by the author and his current and former students on shifting from mobility-focused to access-focused in evaluating the causes and (especially) consequences of traffic congestion on the functioning of cities and their economic agglomerations. This work has turned traffic impact analysis on its head by considering how the spatial arrangement of destinations makes it easier or harder to access them — regardless of the traffic speeds on adjacent roadways.

The Impact of COVID-19 on the Mobility Needs of an Aging Population in Contra Costa County

Status

Complete

Project Timeline

July 1, 2019 - September 30, 2020

Principal Investigator

David Ragland

Project Summary

Meeting the mobility needs of an aging population is a critical challenge facing California. The number of residents age 60 and above will grow to 13.9 million by 2050, representing over 25% of the state’s population, and the number of residents age 85 and above is expected to increase by over 70% between 2010 and 2030. Many older adults, who have been auto dependent, will reduce or stop driving for medical and non-medical reasons, substantially reducing mobility and activity. These limitations increase among low-income older adults and in neighborhoods where mobility options are limited. Transportation agencies are developing plans to expand mobility options beyond driving to address the needs of disabled and older adults. The Coordinated Public Transit–Human Services Transportation Plan (2018), adopted by the Metropolitan Transportation Commission (MTC), prioritizes cost efficient mobility options for seniors, people with disabilities, veterans, and people with low incomes. Contra Costa County (CCC) is implementing an Accessible Transportation Strategic (ATS) Plan, which supports a similar strategy. The problem and challenge with these plans are to provide information for appropriate and efficient implementation. The Contra Costa Transportation Authority (CCTA) is embarking on several major programs to enhance mobility for all residents, including older adults and disabled persons. Travel options and quality of life for older adults can be greatly enhanced if efforts are made to develop innovative mobility solutions beyond use of private vehicles, including (a), making transit improvements based on need, (b) encouraging rideshare services to accommodate those with disabilities, (c) offering resources for people at risk for missing important activities due to lack of transportation or mobility loss, (d) identifying and focusing on mobility challenged geographic areas and demographic groups, and (e) helping older adults to age in place. A previous study conducted by SafeTREC in 2017/18 on older adult mobility in CCC addressed these topics. The research team will work with the CCTA to use research findings from this previous work, in conjunction with a follow-up survey, to inform implementation of the ATS plan and other plans with similar goals. Major steps in the project are: (i) convene a work group of CCTA, MTC, and community stakeholders and others doing research and practice in this area that will provide input on the deliverables; (ii) synthesize the results of the CCC Older Adult Mobility Survey and ATS plan to help design the proposed follow-up survey (80% of 500 participants in the 2017-18 survey age 55+ agreed to follow-up); (iii)develop a toolkit that translates methods and findings from the 2017/18 project and the current 2019/20 project; and (iv) communicate findings to stakeholders.