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Open Access Publications from the University of California


The Sustainable Freight Research Center is part of the STEPS+ Consortium at the UC Davis Institute of Transportation Studies (ITS-Davis).

Sustainable Freight Research Center

There are 3 publications in this collection, published between 2018 and 2020.
Research Reports (3)

Development of a Freight System Conceptualization and Impact Assessment (Fre‐SCANDIA) Framework

The freight system is a key component of California’s economy, but it is also a critical contributor to a number of externalities. Different public agencies, private sector stakeholders, and academia engaged in the development of the California Sustainable Freight Action Plan (CSFAP). This plan put forward a number of improvement strategies/policies. However, the freight system is so complex and multifaceted, with a great number of stakeholders, and freight operational patterns, that evaluating or assessing the potential impacts of such strategies/policies is a difficult task. To shed some light, this project develops a freight system conceptualization and impact assessment framework of the freight movements in the State. In doing this, the framework assesses the impact of commodity flows from different freight industry sectors along supply chains within, originating at, or with a destination in the state of California.

The conceptual framework analyzes the freight flows in supply chains, and the type of freight activity movements and modes. The framework uses a Life Cycle Assessment (LCA) Methodology. The framework could be extended to support multidimensional cost/benefit appraisals for both direct benefits (e.g., delays, costs, accidents, maintenance) and social benefits to non-users which include impacts on regional and national economies as well as environmental and health impacts. This report discusses the main components of the conceptual framework based on a comprehensive review of existing methodologies. The implementation is limited to the Life Cycle Impact Assessment (LCIA) following the Environmental Protection Agency’s Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI).

The report describes the results from the LCIA implementation for a number of case studies. Specifically, the work estimated the impacts of moving a ton of cargo over a mile for various industry categories and commodity types. These results show the relative difference across industries and commodities and could serve to identify freight efficiency improvement measures in the state of California.

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Analytical Modeling Framework to Assess the Economic and Environmental Impacts of Residential Deliveries, and Evaluate Sustainable Last-Mile Strategies

In the last decade, e‐commerce has grown substantially, increasing business‐to‐business, business‐to‐consumer, and consumer‐to‐consumer transactions. While this has brought prosperity for the e-retailers, the ever-increasing consumer demand has brought more trucks to the residential areas, bringing along externalities such as congestion, air and noise pollution, and energy consumption. To cope with this, different logistics strategies such as the introduction of micro-hubs, alternative delivery points, and use of cargo bikes and zero emission vehicles for the last mile have been introduced and, in some cases, implemented as well. This project, hence, aims to develop an analytical framework to model urban last mile delivery. In particular, this study will build upon the previously developed econometric behavior models that capture e-commerce demand. Then, based on continuous approximation techniques, the authors will model the last-mile delivery operations. And finally, using the cost-based sustainability assessment model (developed in this study), the authors will estimate the economic and environmental impacts of residential deliveries under different city logistics strategies.

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Fostering the Use of Zero and Near Zero Emission Vehicles in Freight Operations

California is in the midst of improving its freight system. For example, the California Sustainable Freight Action Plan (CSFAP) established the goal of reaching a 25% increase in freight efficiency, the use of 100,000 zero emission vehicles and equipment (and maximize the number of near zero emission vehicles) in the system, and improving economic competitiveness. Although there are multiple strategies and approaches to help achieve these goals, this study focuses on analyzing the factors to foster the adoption of zero and near-zero emission vehicles. For example, the use of monetary and non-monetary incentives to elucidate behavioral changes (e.g., fleet purchase decisions). This study considered compressed (renewable) natural gas (CNG/RNG), hybrid electric (HE), battery electric (BE) and fuel-cell hydrogen (H2) vehicles. The research team collected information through a web-based stated preference survey sent (in two waves) to fleets and carrier companies to gather data about their economics, and their vehicle purchase preferences. However, the response rate was very small which limited the type of analyses conducted with the data. Alternatively, the study team developed a multi-criteria decision-making tool using a Spherical Fuzzy Analytical Hierarchy Process based on experts’ knowledge. The approach considered the variability in the technical and operational characteristics, market readiness, and other factors related to these technologies. The model helped provides insights about the most appropriate options for different uses (e.g., last mile, long-haul distribution). Specifically, the authors evaluate the alternatives using five criteria: economic; business, incentives & market-related; environmental & regulatory; infrastructure; and safety & vehicle performance factors. The analyses also consider twenty-one sub-criteria, e.g., total cost of ownership, payback period, brand image, financial & non-financial incentives, and public/private fueling/ charging infrastructure availability.

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