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.

Hemcrete is an alternative, environmentally‐friendly building material gaining adherents in Great Britain and other European countries. It is an attractive choice as a building material because it is made from a renewable resource, hemp, a hardy plant that is a close, but non‐hallucinogenic relative of marijuana. This plant is relatively easy to cultivate, requires little in the way of pesticides or fertilizers, and almost all parts can be used for various products from paper to textiles to food.

Hemcrete is made from a mixture of lime, water, and the fibrous outer portion of the hemp plant called the “hurd” or “shive”. When mixed, it is worked and placed much like conventional concrete ‐ hence the name. However, that is where the similarities with concrete end. Hemcrete is not comparable to concrete on a strength basis, and is better described as an alternative insulation product. When built into walls of sufficient thickness, Hemcrete offers high thermal efficiency, and has strong claims to being carbon negative. The purpose of this study
was to evaluate this claim of carbon negativity, and to compare these environmentally friendly qualities against conventional fiberglass batt insulation.

Our model was constructed using two identically sized “walls” measuring eight feet square by one foot in depth, one insulated using Hemcrete, and the other using fiberglass. Our study focused on three areas: water usage, cost, and carbon dioxide emissions. We chose water
usage because we wanted to determine the feasibility of using Hemcrete in the Phoenix metropolitan region where water is a troubled resource. Secondly, we wished to evaluate the claim on carbon negativity, so CO2 equivalents throughout the production process were measured. Finally, we wished to know whether Hemcrete could compete on a cost basis with more conventional insulation methods, so we also built in a price comparison.

Since the cultivation of hemp is currently unlawful in the United States, this study can help determine whether these restrictions should be relaxed in order to allow the construction of buildings insulated with Hemcrete.