1,721,018 research outputs found
Current and Future Post-fire Debris Flow Risk and Roadway Vulnerability in California
No full textThe data are project results for current and future post-fire debris flow assessment of the state of California. The project model was developed largely in 2019-2020 using current and future fire and precipitation data from CalAdapt, USGS watershed geography and geologic characteristics, and roadway data, all publicly available. The work was initially published by UCLA as a technical report (2020) and later refined and published as a journal article (2023)
San Francisco Bay Area Parking Space Inventory
No full textThe San Francisco Bay Area is one of the most progressive transportation regions in the deployment of high-capacity transit and the use of policies to encourage active transportation. Yet, there remains a dearth of knowledge on the abundance and location of parking infrastructure. The extent and location of parking supply, including on-street and off-street spaces, are estimated for the nine-county Bay Area by creating a federated database that joins land use, transportation, parcel, building, and parking code layers to estimate the number and characteristics of parking spaces at the census block scale. This bottom-up parking space inventory results in an estimated 15 million parking spaces in the region: 8.6 million on-street and 6.4 million off-street. Residential parking dominates the share of supply at 70%, followed by commercial at 9.4%. Space density is greatest in downtown San Francisco, Oakland, and San Jose—largely attributed to high-rise structures. On-street parking is dominant in the North Bay, commanding 78% of total parking in Napa, 75% in Solano, 68% in Sonoma, and 67% in Marin County. Parking area constitutes 7.9% of the total incorporated area. Notably, when compared to other southwest cities (Phoenix Metropolitan Area and Los Angeles County), the Bay Area parking supply appears better utilized considering spaces per person, per car, and per job. The density and quantity of parking spaces in the Bay Area are critical insights toward developing targeted policies that encourage active mobility and support affordable housing
Los Angeles County Parking Space Infrastructure Inventory
No full textReplication data for the 2015 article "Parking Infrastructure: A Constraint on or Opportunity for Urban Redevelopment? A Study of Los Angeles County Parking Supply and Growth." We estimate how parking has grown in Los Angeles County from 1950 to 2010. We find that since 1975 the ratio of residential offstreet parking spaces to automobiles in Los Angeles County is close to 1.0 and the greatest density of parking spaces is in the urban core while most new growth in parking occurs outside of the core. 14% of incorporated land in Los Angeles County is committed to parking. Uncertainty in our space inventory is attributed to our building growth model, onstreet space length, and the assumption that parking spaces were created as per the requirements
Phoenix Metro Parking Space Infrastructure Inventory
No full textA parking inventory for metropolitan Phoenix, Arizona, USA is developed by cross-referencing geospatial cadastral and roadway data with minimum parking requirements. Historical growth of parking is also estimated by linking year of property development to required off-street and nearby on-street parking spaces. As of 2017, we estimate that there were 12.2 million parking spaces in the metropolitan region with 4.04 million inhabitants, 2.86 million registered personal vehicles, and 1.84 million jobs. Growth of parking in metro Phoenix has also been significant; since 1960, 10.9 million spaces have been added to the region compared to a population growth of 3.41 million, vehicle fleet growth of 2.63 million, and employment growth of 1.56 million jobs. Since the 2008 recession, parking growth in metro Phoenix has significantly slowed, but continued urban growth combined with substantial minimum parking requirements may promote more parking infrastructure than is needed
Methodology for the Environmental Life-cycle Assessment of Los Angeles Metro’s Orange Bus Rapid Transit and Gold Light Rail Transit Lines
Full text linkabstract: 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
Data Compendium: Vulnerability of California electricity system assets to wildfires and post-wildfire debris flows
No full textThe data are project results for current and future wildfire and post-fire debris flow threat to electrical infrastructure in California. The project assessed conditions using current and future fire data from Cal-Adapt, and current and future wildfire and post-fire debris flow threat from Li and Chester (doi: 10.1088/2634-4505/acb3f5), which are publicly available. Transmission line, substation, and power generation threats were assed. The work was completed in 2024 and published as a journal article in 2025
Environmental Life Cycle Assessment of San Francisco Bay Area Muni Light Rail and Rapid Transit with Wholesale and Renewable Electricity
Full text linkabstract: Results are available at www.transportationlca.org
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): http://dx.doi.org/10.1088/1748-9326/4/2/02400
Human and Organizational Factors that Contributed to the US-Canadian August 2003 Electricity Grid Blackout
Full text linkabstract: The US-Canadian electricity grid is a network of providers and users that operate almost completely independently of one another. In August of 2003, First Energy’s (FE) Harding-Chamberlain transmission line near Akron, Ohio went offline starting a series of cascading failures that eventually led to 8 US states and 1 Canadian province totaling nearly 50 million people without power. The failure of transmission lines are common occurrences relating to the inability to exactly predict the electricity demand at any time (as will be discussed later in this document). The inability to properly monitor and react across multiple organizations to the downed line was the true failure that led to the blackout. This outage not only left homes and businesses without power but paralyzed critical public services such as transportation networks and hospitals. The estimated cost of the outage is between 4 and 6 billion US dollars
Metropolitan-scale Building Infrastructure Environmental Life Cycle Assessment: Los Angeles’ Embedded Impacts
Full text linkabstract: Building energy assessment often focuses on the use of electricity and natural gas during the use phase of a structure while ignoring the energy investments necessary to construct the facility. This research develops a methodology for quantifying the “embedded” energy and greenhouse gases (GHG) in the building infrastructure of an entire metropolitan region. “Embedded” energy and GHGs refer to the energy necessary to manufacture materials and construct the infrastructure. Using these methods, a case study is developed for Los Angeles County
High-speed Rail, Aircraft and Automobile Environmental Futures in California
No full textabstract: California high-speed rail will add a new long-distance transportation service and has the potential to reduce greenhouse gas emissions and damages to human health and the environment. A life-cycle assessment is performed and results reported for the California corridor in the 2030 to 2050 time period. Several future infrastructure and operating characteristics are evaluated to determine the critical characteristics that should be focused on when designing, constructing, and operating the system. This research provides results for and discussions of the possible futures of California long-distance transportation service with a focus on a multi-modal system that includes high-speed rail.This working paper has been superseded by the author's Environmental Research Letters (ERL) publication, available at http://dx.doi.org/10.1088/1748-9326/7/3/034012. The working paper PDF is no longer available and interested readers should instead access the ERL manuscript
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