Browsing by Subject "Greenhouse gases"

Now showing 1 - 6 of 6
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    Dedicated transit lanes help attract riders, reduce carbon emissions
    (Center for Transportation Studies, University of Minnesota, 2024-06) Center for Transportation Studies
    This research brief summarizes report CTS 23-09, The Value of Dedicated Right of Way (ROW) to Transit Ridership and Carbon Emissions, that examined the influence of four types of ROW on transit ridership and emissions.
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    Evaluating on-farm sampling strategies and corresponding gas emission estimation methods for livestock and poultry barns
    (2022-08) Soriano, Noelle Cielito
    The need for gas emission research is driven by multiple stakeholders to address avariety of concerns and priorities that stem from environmental, human, and animal impacts of gas emissions from barns. In this work, I first provide background on the mechanism of gas emission from these systems and an overview of emission estimation strategies in the literature. This is followed by a presentation of two thesis projects, which demonstrate outcomes and challenges related to different emission estimation strategies. In the first project, I investigate airflow patterns and estimate ammonia (NH3) and carbon dioxide (CO2) emissions using a multi-airspace model for a naturally ventilated deep-pit cattle barn, with discrete gas concentration data. The second project uses a mass balance approach to estimate volatile solids (VS) losses and NH3 emissions from a naturally ventilated poultry barn based on material flows in and out of a barn. Each estimation strategy is evaluated based on the practicality of the sampling approach in specific housing styles, and whether emission estimates are comparable to current emission estimation methods for each system. Findings from these two projects show that, ultimately, there will always be limitations to the various available emission estimation strategies, particularly related to in-barn sample collection. Understanding the appropriate application of each of these approaches is important when selecting an emission estimation approach that will allow researchers to obtain representative emission estimates from a variety of livestock and poultry systems.
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    Reducing greenhouse gas emissions from transportation and land use: Lessons from West Coast states
    (Journal of Transport and Land Use, 2018) Lewis, Rebecca; Zako, Robert; Biddle, Alexis; Isbell, Rory
    Planners and policymakers in the United States increasingly recognize climate change as a critical challenge. Because the transportation sector accounts for one-third of all greenhouse gas emissions (GHGs) linked to climate change, some states—including California, Oregon, and Washington—have passed legislation to reduce GHGs from transportation. Much of the work to date has focused on modeling impacts and evaluating performance of different strategies. Instead, this paper focuses on policy adoption and implementation. This re-search relies on document analysis and stakeholder interviews to ex-amine state efforts to reduce GHGs by examining goals, plans, actions, and results. While these states have all established statutory goals to reduce GHGs, planning, implementation, and monitoring vary across states. California and Oregon rely on state- and metropolitan-level planning, while Washington relies on a state approach. California has enacted funding programs to implement strategies to achieve reductions and worked to reduce regulatory barriers to compact development. All states monitor levels of GHGs, but the impact of plans is often unexamined. Though West Coast states have taken initial steps to enact goals and require scenario plans, states must provide funding or regulatory relief while improving monitoring in order to achieve ambitious goals to reduce GHGs from transportation.
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    Reducing Greenhouse Gas Emissions From Transportation Sources in Minnesota
    (University of Minnesota Center for Transportation Studies, 2008-06) Boies, Adam; Kittelson, David B.; Watts, Winthrop J.; Lucke, Jan; McGinnis, Laurie; Marshall, Julian; Patterson, Tyler; Nussbaum, Peter; Wilson, Elizabeth
    The 2007 Minnesota Next Generation Energy Act established goals for reducing statewide greenhouse gas (GHG) emissions by 15% by 2015, 30% by 2025, and 80% by 2050, relative to 2005 levels. This report investigates strategies for meeting those reductions in Minnesota?s transportation sector, which produces approximately 24% of total state GHG emissions. The study focuses on three types of emission-reduction strategies: those that improve vehicle fuel economy, those that reduce the number of vehicle-miles traveled, and others that decrease the carbon content of fuel. The researchers used a quantitative model to test the effectiveness of specific strategies for GHG emission reduction from transportation in Minnesota. Modeled scenario outcomes depend strongly on input assumptions, and lead us to the following three main conclusions. 1. Meeting state goals will require all three types of policies. For example, Minnesota could adopt a GHG emissions standard, a low-carbon fuel standard, and comprehensive transit and Smart Growth policies. 2. Technologies are available today to substantially improve fuel economy and vehicle GHG emissions. Requiring these technologies could save Minnesota consumers money and better insulate them from oil price volatility. 3. Changes in vehicle-miles traveled (VMT) have a strong impact on whether the goals can be met, and increases in VMT can offset GHG reductions. Overall, the research indicates that the goals can be met, but achieving them requires consistent and concerted action beginning immediately.
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    A Smaller Carbon Footprint: Research Suggests Combining Strategies to Meet Legislative Goals in the Transportation Sector
    (University of Minnesota Center for Transportation Studies, 2008-06) Boies, Adam; Kittelson, David B.; Watts, Winthrop J.; Lucke, Jan; McGinnis, Laurie; Marshall, Julian; Nussbaum, Peter; Wilson, Elizabeth
    The 2007 Minnesota Next Generation Energy Act established goals for reducing statewide greenhouse gas (GHG) emissions by 15% by 2015, 30% by 2025, and 80% by 2050, relative to 2005 levels. This document summarizes a longer report which investigates strategies for meeting those reductions in Minnesota's transportation sector, which produces approximately 24% of total state GHG emissions.
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    The Value of Dedicated Right of Way (ROW) to Transit Ridership and Carbon Emissions
    (Center for Transportation Studies, University of Minnesota, 2023-12) Cao, Jason; Tao, Tao; Johnson, Isak; Huang, Hannah
    Transit agencies have adopted various types of right of way (ROW) for transit routes, including mixed traffic, semi-exclusive ROW, exclusive ROW, and grade separation, but few empirical studies have quantified their impacts on ridership and carbon emissions. Using data collected from transit agencies in the US, this research aimed to examine the impacts of dedicated ROW. We applied the gradient boosting decision tree method to estimate the nonlinear relationships between yearly route-level transit ridership and five types of independent variables, with a focus on ROW. The results showed that ROW contributes 18% of the power to predicting transit ridership, which is the largest among all the independent variables. Upgrading from mixed traffic to semi-exclusive ROW could boost ridership by 70,000, on average. A further upgrade to an exclusive ROW could add 3.68 million passengers. Moreover, the number of stops, transit route commence year, population density, signal priority, number of park-and-ride facilities, headway, network density, and route length all have non-trivial contributions to predicting ridership. Upgrading the operating environment could substantially reduce carbon emissions, up to 6.37 million pounds of CO2e. Overall, elevating ROW levels could notably enhance transit ridership and reduce carbon emissions, locating transit routes in the areas with adequate population density and network density could improve their performance, deploying signal priority and improving transit frequency also help, and increasing the share of electric buses could further decrease carbon emissions.