policy brief

E-commerce is Reshaping the Warehousing Landscape – and it May Impact Disadvantaged Communities

Abstract

Prior to the last decade, the logistics industry trended towards the development of mega-warehouse facilities in suburban settings far from core markets, creating a phenomenon known as logistics sprawl. This trend is particularly prominent in Southern California (Figure 1). Since the 2008-2009 economic crisis, however, the trend has shifted. The rise of e-commerce may have influenced supply chain decisions to locate warehouses and distribution centers closer to denser urban areas to enable faster deliveries to consumers. The changes in size and spatial distribution of warehouses and distribution centers as well as the environmental and equity implications of these changes are not fully understood. As warehouses and distribution centers locate in denser urban areas, they may introduce additional diesel truck traffic into disadvantaged and low-income communities.To gain a better understanding of how the spatial distribution and size of freight facilities are changing and the implications of these changes for disadvantaged and low-income communities, researchers at the University of California, Davis analyzed aggregate data about the number of warehouses and distribution centers and disaggregate real estate data of purchases and leases during the last three decades in California. They also analyzed the relationship between freight facilities and communities of concern using the California Environmental Protection Agency’s CalEnviroScreen 3.0 tool. The research focused on the San Diego, Los Angeles, San Francisco, San Joaquin Valley, and Sacramento regions. Key findings from the research are presented in this brief.

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.

research report

Travel Behavior Changes Among Users of Partially Automated Vehicles

Abstract

Partially automated battery electric vehicles (BEVs) are being sold to and used by consumers. Estimates indicate that as of the end of 2019, there were over 700,000 Partially Automated Tesla Vehicles—the subject of this study—on the roads globally. Despite this, little research has been done to understand how they may be changing travel behavior. In this study, qualitative interviews with 36 users of Tesla battery electric vehicles with Autopilot were conducted. The goal of this was to understand how Autopilot is used, user experiences of the system, and whether the system has any impact on drivers’ travel behavior. The focus of the last of these aims was to determine whether Autopilot could cause or was causing an increase in vehicle miles traveled (VMT) among the study participants. Results from the interviews showed that partial automation leads to consumers traveling by car more and being more willing to drive in congested traffic. These changes are due to increased comfort, reduced stress, and increased relaxation due to the partial automation system, and because of the lower running costs of a BEV. The results also point to a need for further research of partially automated vehicles that are already on the market, as 11 of 17 reasons for increased vehicle miles traveled that have been identified in modeling studies of fully automated vehicles (not yet commercially available) applied to users of Autopilot.

research report

Learning to Collaborate: Lessons Learned from Governance Processes Addressing the Impacts of Sea Level Rise on Transportation Corridors Across California

Abstract

This study was designed to identify lessons learned from experiences of multi-stakeholder collaboration in governance processes focused on adaptation to sea level rise for specific transportation corridors/assets across different areas of California. Four transportation assets in California were selected as case studies: State Route 37 in the Bay Area; the Cardiff Beach Living Shorelines Project and the LOSSAN railroad at Del Mar in San Diego County; and the Port of Long Beach in Los Angeles County. The study methods included attendance of policy meetings; document analysis; and interviews of staff at (local, regional, and state) government bodies, transportation agencies, climate collaboratives, etc. The study identified three major governance challenges shared among these cases: (1) stakeholder involvement or collaboration with ‘unusual’ partners; (2) jurisdictional fragmentation; and (3) lack of funding. The lessons learned to address these challenges were: (a) include a wide range of stakeholders early on in the project; (b) identify an intermediary or facilitator with relevant knowledge and social capital with the stakeholders; (c) establish a forum for negotiations and information exchange; (d) draft a memorandum of understanding with the rules of collaboration; (e) appoint a project manager to tie all the project parts and stakeholders together and sustain engagement; (f) structure the collaboration in tiers from technical/operational to executive/political; (g) explore options to make any given project a multi-benefit project; (h) advocate for a multi-year stream of funding rather than a lump sum; (i) leverage collaboration for funding and highlight, to potential funders, the collaborative element as a means to increase the efficiency of their investment. Issues to consider when deriving lessons from other jurisdictions were: differences in capacity, or available resources and staff; the numbers of actors involved; pre-existing positive collaborative relationships between the actors; exposure of transportation assets to sea-level rise; existing vulnerabilities of the corridor/asset; and the economic relevance of the corridor/asset.

research report

Research Synthesis for the California Zero Traffic Fatalities Task Force

Publication Date

April 1, 2020

Author(s)

Bingchu Chen, Brian D. Taylor, Dillon Fitch-Polse, Katherine Chen, Offer Grembek, Salvador Grover, Sonia Anthoine, Yu Hong Hwang

Abstract

This research synthesis consists of a set of white papers that jointly provide a review of research on the current practicefor setting speed limits and future opportunities to improve roadway safety. This synthesis was developed to inform thework of the Zero Traffic Fatalities Task Force, which was formed in 2019 by the California State Transportation Agencyin response to California Assembly Bill 2363 (Friedman). The statutory goal of the Task Force is to develop a structured,coordinated process for early engagement of all parties to develop policies to reduce traffic fatalities to zero. Thisreport addresses the following critical issues related to the work of the Task Force: (i) the relationship between trafficspeed and safety; (ii) lack of empirical justification for continuing to use the 85th percentile rule; (iii) why we need toreconsider current speed limit setting practices; (iv) promising alternatives to current methods of setting speed limits;and (v) improving road designs to increase road user safety.

research report

Transportation, Quality of Life, and Older Adults

Abstract

Driving rates decline with age as vision, health, and cognitive ability cause some older adults to give up driving. Many older adults first gradually limit their driving as they age and later cease driving. Using data from the Health and Retirement Study (HRS), which surveys 22,000 older Americans every two years, the research team modeled the extent to which older drivers limit and stop driving. The data are longitudinal, allowing analysis of changes in driving and residential location as well as cohort effects that could not be studied using standard, cross-sectional survey data that only allow comparisons of different people at one point in time. The analysis shows that decisions to limit and eventually stop driving vary in statistically significant ways with sex, age, and health conditions. These relationships also differ by birth cohort. More recent cohorts are less likely to stop and limit driving than older ones. To analyze the relationship between residential location and driving behavior, the team linked the HRS data to census-tract-level data from the US Census and a categorization of community types. The research team found that residential density and other features of urban built environments are associated with changes in driving and vehicle ownership. HRS survey participants showed a greater propensity to reduce or give up driving if they resided in denser, more diverse, transit-oriented neighborhoods. People who prefer non-automotive modes of transportation may have been more likely than others to self-select into walkable and transit-rich areas. The findings should inform California’s strategic planning for aging and its community development policies. In addition to informing planning for the next generation of older Californians, this study demonstrated the utility of longitudinal information and models for the understanding of older populations and their travel.