Public transit systems are often accepted as energy and environmental improvements to automobile travel, however, few life cycle assessments exist to understand the effects of implementation of transit policy decisions. To better inform decision-makers, this project evaluates the decision to construct and operate public transportation systems and the expected energy and environmental benefits over continued automobile use. The public transit systems are selected based on screening criteria. Initial screening included advanced implementation (5 to 10 years so change in ridership could be observed), similar geographic regions to ensure consistency of analysis parameters, common transit agencies or authorities to ensure a consistent management culture, and modes reflecting large infrastructure investments to provide an opportunity for robust life cycle assessment of large impact components. An in-depth screening process including consideration of data availability, project age, energy consumption, infrastructure information, access and egress information, and socio-demographic characteristics was used as the second filter. The results of this selection process led to Los Angeles Metro’s Orange and Gold lines.

In this study, the life cycle assessment framework is used to evaluate energy inputs and emissions of greenhouse gases, particulate matter (10 and 2.5 microns), sulfur dioxide, nitrogen oxides, volatile organic compounds, and carbon monoxide. For the Orange line, Gold line, and competing automobile trip, an analysis system boundary that includes vehicle, infrastructure, and energy production components is specified. Life cycle energy use and emissions inventories are developed for each mode considering direct (vehicle operation), ancillary (non-vehicle operation including vehicle maintenance, infrastructure construction, infrastructure operation, etc.), and supply chain processes and services. In addition to greenhouse gas emissions, the inventories are linked to their potential for respiratory impacts and smog formation, and the time it takes to payback in the lifetime of each transit system.

Results show that for energy use and greenhouse gas emissions, the inclusion of life cycle components increases the footprint between 42% and 91% from vehicle propulsion exclusively. Conventional air emissions show much more dramatic increases highlighting the effectiveness of “tailpipe” environmental policy. Within the life cycle, vehicle operation is often small compared to other components. Particulate matter emissions increase between 270% and 5400%. Sulfur dioxide emissions increase by several orders of magnitude for the on road modes due to electricity use throughout the life cycle. NOx emissions increase between 31% and 760% due to supply chain truck and rail transport. VOC emissions increase due to infrastructure material production and placement by 420% and 1500%. CO emissions increase by between 20% and 320%. The dominating contributions from life cycle components show that the decision to build an infrastructure and operate a transportation mode in Los Angeles has impacts far outside of the city and region. Life cycle results are initially compared at each system’s average occupancy and a breakeven analysis is performed to compare the range at which modes are energy and environmentally competitive.

The results show that including a broad suite of energy and environmental indicators produces potential tradeoffs that are critical to decision makers. While the Orange and Gold line require less energy and produce fewer greenhouse gas emissions per passenger mile traveled than the automobile, this ordering is not necessarily the case for the conventional air emissions. It is possible that a policy that focuses on one pollutant may increase another, highlighting the need for a broad set of indicators and life cycle thinking when making transportation infrastructure decisions.

The goal of this working paper is to provide the methodological background for several upcoming reports and peer-reviewed journal publications. This manuscript only provides background methodology and does not show or interpret any of the results that are being generated by the research team. The methodology is consistent with the transportation LCA approach developed by the author in previous research. The discussion in this working paper provides the detailed background data and steps used by the research team for their assessment of Los Angeles Metro transit lines and a competing automobile trip.

As the number of heat waves are expected to increase significantly into the future in the U.S. Southwest, new insight is needed into how urban infrastructure can be repositioned to protect people. In the Phoenix metro area infrastructure have largely been deployed over the past half century, during a time when climate change was not a concern. Now, as the county struggles to protect people from heat, there is a need to reassess how existing and new infrastructure can be positioned to reduce health impacts while improving sustainability. Using a neighborhood in Mesa, Arizona as a case study, we assess how changes to transportation infrastructure, building infrastructure, and landscaping can reduce heat exposure. A number of strategies are considered including the optimal deployment of heat refuges, deploying less convective surface materials, and deploying more thermally preferable building materials. The suite of strategies could be considered by cities throughout the Phoenix metro area.

As average temperatures and occurrences of extreme heat events increase in the Southwest, the water infrastructure that was designed to operate under historical temperature ranges may become increasingly vulnerable to component and operational failures. For each major component along the life cycle of water in an urban water infrastructural system, potential failure events and their semi-quantitative probabilities of occurrence were estimated from interview responses of water industry professionals. These failure events were used to populate event trees to determine the potential pathways to cascading failures in the system. The probabilities of the cascading failure scenarios under future conditions were then calculated and compared to the probabilities of scenarios under current conditions to assess the increased vulnerability of the system. We find that extreme heat events can increase the vulnerability of water systems significantly and that there are ways for water infrastructure managers to proactively mitigate these vulnerabilities before problems occur.

The Food-Energy-Water (FEW) nexus is the interaction and the interdependence of the food, energy and water systems. These interdependencies exist in all parts of the world yet little knowledge exists of the complexity within these interdependent systems. Using Arizona as a case study, systems-oriented frameworks are examined for their value in revealing the complexity of FEW nexus. Industrial Symbiosis, Life Cycle Assessment (LCA) and Urban Metabolism are examined. The Industrial Symbiosis presents the system as purely a technical one and looks only at technology and hard infrastructure.

The LCA framework takes a reductionist approach and tries to make the system manageable by setting boundary conditions. This allows the frameworks to analyze the soft infrastructure as well as the hard infrastructure. The LCA framework also helps determine potential impact. Urban Metabolism analyzes the interactions between the different infrastructures within the confines of the region and retains the complexity of the system. It is concluded that a combination of the frameworks may provide the most insight in revealing the complexity of nexus and guiding decision makers towards improving sustainability and resilience.

In the economic crisis Detroit has been enduring for many decades, a unique crisis has emerged with the provision of water that is normally not seen in the developed world. The oversized, deteriorating, and underfunded water provision system has been steadily accruing debt for the water utility since population began to decrease in the 1950s. As a result, the utility has instated rate increases and aggressive water shut off policies for non-paying residents. Residents have consequentially claimed that their human right to water has been breeched.

In this report, I analyze possible solutions to the water crisis from both the water utility and resident perspectives. Since all utility management solutions have very serious limitations on either side of the argument, I have chosen a set of technologies to consider as a part of an impact mitigation plan that can provide alternative sources of water for the people who no longer can rely on municipal water. I additionally propose an adaptive management plan to evaluate the effects of using these technologies in the long-term. The monitoring of the effects of technological mitigations might also help determine if sustainability (efficiency and equity) could be an attainable long-term solution to Detroit’s water crisis.

Results are available here. 

The environmental life cycle assessment of electric rail public transit modes requires an assessment of electricity generation mixes. The provision of electricity to a region does not usually adhere to geopolitical boundaries. Electricity is governed based on lowest cost marginal dispatch and reliability principles. Additionally, there are times when a public transit agency may purchase wholesale electricity from a particular service provider. Such is the case with electric rail modes in the San Francisco Bay Area.

An environmental life cycle assessment of San Francisco Bay Area public transit systems was developed by Chester and Horvath (2009) and includes vehicle manufacturing/maintenance, infrastructure construction/operation/maintenance, energy production, and supply chains, in addition to vehicle propulsion. For electric rail modes, vehicle propulsion was based on an average electricity mix for the region. Since 2009, new electricity contract information and renewable electricity goals have been established. As such, updated life cycle results should be produced.

Using recent wholesale electricity mix and renewable electricity goal data from the transit agencies, updated electricity precombustion, generation, transmission, and distribution environmental impacts of vehicle propulsion are estimated. In summary, SFMTA Muni light rail is currently purchasing 100% hydro electricity from the Hetch Hetchy region of California and the Bay Area Rapid Transit (BART) system is purchasing 22% natural gas, 9% coal, 2% nuclear, 66% hydro, and 1% other renewables from the Pacific Northwest . Furthermore, the BART system has set a goal of 20% renewables by 2016. Using the GREET1 2012 electricity pathway, a life cycle assessment of wholesale and renewable electricity generation for these systems is calculated.

Chester and Horvath (2009)