Chester is leading research efforts to develop an understanding of how urban systems have been deployed, frameworks for assessing their energy and environmental impacts, and strategies for transitioning infrastructure systems for twenty-first century needs. His goal is to develop the science for understanding how embedded infrastructure design enables the emergent behaviors that we often consider to be unsustainable, and for analyzing and breaking path dependencies that will aid in transitioning to lower energy and environmental impact futures. His graduate work through 2008 largely focused on transportation infrastructure and since then he has focused more broadly on the interface of infrastructure and urbanization processes. Approximately half of his work is focused on the assessment of transportation systems and the other half land use, water, and energy systems, including their interdependencies. He has begun studying the role that infrastructure plays in contributing to extreme heat events in the US Southwest. His long-term research goals are to advance our understanding of how urban infrastructure design should balance the life-cycle benefits and costs of integrated systems with sensitivity to social-equity, economic growth, and future climate-constraints.
Exposure to heat is a growing public health concern in many cities across the globe. In the US, Southwest cities have experienced increasing numbers of heat waves in the past few decades, and global climate models project significant increases in both the duration and intensity of these extreme events. Facing these challenges, very little is known about how people are exposed to heat during their day-to-day activities as they interact with urban infrastructure. To understand exposure, factors including the types of homes people live in (and whether they have and use air conditioning), their mobility choices, the quality of the infrastructure (e.g., shading, landscaping, and material choice), their work situation (e.g., air conditioned office versus outdoor worker), and their activity profiles must be considered. A systematic framework that any city can use to understand how people are exposed to heat and proactively mitigate risk is needed.
To create insight into how people are exposed to heat, this work will develop an Urban Activity Heat Simulation (UAHS) platform that will join (1) a model of residential and workplace exposure, (2) travel simulations for automobile use, public transit, and biking/walking, (3) urban infrastructure characteristics, (4) high-resolution urban climate data, and (5) a model of exposure thresholds. UAHS will be developed using Phoenix, Arizona and Los Angeles, California as case studies. Heat performance models for buildings will be combined with surveys of home and work activities to assess how people experience heat indoors. Using national and regional travel surveys combined with detailed travel models, simulations of how people move throughout cities will be developed. Downscaled climate models will be used to estimate present and future outdoor conditions in both cities. Information on infrastructure including materials, landscaping, and shading will also be used to develop estimates of outdoor exposure. Combining simulated exposures with health records will provide new insight into dangerous heat exposure profiles. The platform will be validated with in situ monitoring. UAHS will be developed with the goal of enabling any city to build upon the platform for their unique population and infrastructure.
We are developing frameworks for integrating infrastructure analysis, life cycle assessment, and behavioral analysis for coupled transportation and land use assessment. As cities consider strategies for reducing the energy and environmental intensity of urban activities, new methods are needed for coupling infrastructure investments with behavioral changes. We are joining life cycle assessment with behavioral assessment to understand how the investment in new transit infrastructure or neighborhood redevelopment results in upfront cost and environmental impacts (e.g., in the construction of a building or light rail system) but long run economic and environmental benefits from activity changes (such as less automobile travel and lower household energy use). Using new transit systems in Phoenix and Los Angeles as case studies, we have developed an integrated transportation and land use life cycle assessment (ITLU-LCA) framework.
Infrastructure design and decisions can significantly impact the behaviors and activities in cities. The hard infrastructure systems that dominate land use and supply critical services are the result of decades, sometimes centuries, of decisions. While these systems have been the foundation on which tremendous growth and value has taken place, as we become more aware of the environmental and social consequences of cities, a better understanding is needed of how we can redesign these systems for twenty-first century goals. Using Phoenix and Los Angeles as case studies, we have developed historical growth models for roadways, parking and buildings. We connect this growth with information on how the infrastructure was used and identify patterns in the relationship between infrastructure and behavior to help cities rethinking future infrastructure investment.
Frameworks for the environmental life cycle assessment of transportation systems have become critically important as new vehicle technologies and alternative energy pathways develop. Traditionally, impacts from transportation systems have been associated with the operational effects of vehicles. As our knowledge of the complexity of transportation systems grows and policies and decisions take hold to reduce the impacts of mobility, broader thinking is needed for transportation services. We have developed a life cycle assessment framework for transportation services that includes infrastructure (construction, operation, and maintenance), vehicles (manufacturing and maintenance), energy production, and supply chain effects, in addition to propulsion. We have used this framework to assess a variety of systems and policies and show how life cycle thinking can provide unique information to a multitude of stakeholders.
Environmental LCA of Passenger Transportation Modes in the United States
Extensive infrastructures and supply chains support transportation services in the US and these systems produce significant environmental effects in the life cycle of passenger modes. We develop a framework for assessing infrastructure, vehicles, energy production, and supply chains, in addition to vehicle propulsion, for typical United States modes (autos, buses, heavy rail, light rail, and aircraft).
Regional Transportation LCA
We extend the aforementioned framework to major metropolitan areas in the United States to assess the regionalized life cycle effects of passenger transportation services. Using travel surveys and local infrastructure data, the life cycle energy use and air emissions of cities can be estimated.
Long-distance Transportation: High-speed Rail and Future Auto and Air Travel
Intercity passenger travel is dominated by automobile and air modes and the introduction of high-speed rail creates an opportunity for reducing long-distance transportation environmental impacts. The deployment of new long-distance transportation modes such as high-speed rail may require significant infrastructure investment which results in environmental impacts. Over time, however, the adoption of these new modes produces an opportunity for significantly reducing the environmental impacts of long-distance travel. Using the life cycle assessment framework, the deployment of high-speed rail in California is assessed against future improvements in aircraft engine performance and emerging automobile technologies.
Across the United States there is strong interest in high-capacity transit investment and the planning for new transit modes is often positioned to help meet energy reduction and environmental goals. Urban high-capacity transit systems provide opportunities for shifting travelers from automobiles, can induce demand for biking and walking, and can create opportunities for land use redevelopment. In cities across the United States including Boston, Chicago, New York, Phoenix, Los Angeles, and San Francisco, we are developing life cycle assessment methods for assessing the long-term effects of public transit investment.
Electric and Hybrid Vehicles
The life cycle impacts of electric vehicles is dependent on several critical factors (including battery size, battery energy density, charging mix, and technology use behavior) and the monetization of changes in damages from air pollution across the life cycle offers an opportunity to evaluate emerging technologies in a consistent impact assessment framework. With researchers at Carnegie Mellon University, we develop such a framework and use it to identify the confluence of technological characteristics that are needed to produce a reduction of public health, climate change, and oil displacement costs from electric vehicles.
The vulnerability to heat of urban populations is a combination of social and built environment (infrastructure) factors. To date, heat vulnerability research has largely been focused on social factors (including age, chronic disease, poverty level, and English proficiency, among others) and few studies have considered how infrastructure enables or restricts access to cooling. New methods are needed for i) categorizing and quantifying the significance of infrastructure systems in providing protection from heat, and ii) joining social and infrastructure vulnerability to heat indices into a single framework that will allow city agencies to prioritize investments. Through a joint National Science Foundation sponsored research project we are developing such a framework through collaboration with public health, medical, social science, urban planning, and energy policy researchers at the University of California, Los Angeles.
Freight activities are a major portion of a region's energy use and environmental impacts, are central to economic activity, and have unique characteristics (long-distance, long vehicle lifetimes, and intra-region behavior) that, in sum, require unique strategies for reducing impacts.
Life Cycle Assessment of Goods Movement in California
An energy consumption and air emissions life cycle assessment that includes vehicle (manufacturing and maintenance), infrastructure (construction, operation, and rehabilitation), and energy production, in addition to propulsion, is developed for truck, rail, and ocean going vessel travel associated with California. The project was sponsored by the California Air Resources Board's through their T-6 Measure to reduce freight emissions for the state's Assembly Bill 32 greenhouse gas goals. The potential for mode shifting and alternative vehicles and fuels is considered and a California freight life cycle assessment framework is developed.
Prioritizing Strategies for Reducing Vehicle Emissions at the Mariposa Point of Entry
The Mariposa Point of Entry at the Arizona-Mexico border is a critical infrastructure for inspecting passenger and freight vehicles. While there have been major infrastructure upgrades, there remains significant opportunities for reducing air emissions at the port. Infrastructure, technology, and logistical strategies are developed for passenger and freight vehicles to reduce emissions as part of a US Environmental Protection Agency grant.
Cities are complex systems that take in resources, produce desirable and undesirable products, accumulate resources, and output waste. The interdependencies of infrastructure systems and growing city supply chains raises important questions about the sustainability of metropolitan regions. Urban Metabolism is a systems-oriented framework for assessing the flows of resources in to and out of cities. Through several projects (including the assessment of the water-energy nexus in Arizona, transportation energy use in Phoenix, and resource use in Los Angeles), we are creating new methods for analyzing resource use and its impacts, at high spatial and temporal resolutions, using emerging rich datasets from cities.