scholarly journals Potential Urban Air Mobility Travel Time Savings: An Exploratory Analysis of Munich, Paris, and San Francisco

2021 ◽  
Vol 13 (4) ◽  
pp. 2217
Author(s):  
Raoul Rothfeld ◽  
Mengying Fu ◽  
Miloš Balać ◽  
Constantinos Antoniou
Keyword(s):  
San Francisco ◽  
Urban Areas ◽  
Metropolitan Region ◽  
Process Time ◽  
Base Case ◽  
Urban Air ◽  
Travel Times ◽  
Bay Area ◽  
Travel Time Savings ◽  
Distributed Propulsion

The advent of electrified, distributed propulsion in vertical take-off and landing (eVTOL) aircraft promises aerial passenger transport within, into, or out of urban areas. Urban air mobility (UAM), i.e., the on-demand concept that utilizes eVTOL aircraft, might substantially reduce travel times when compared to ground-based transportation. Trips of three, pre-existent, and calibrated agent-based transport scenarios (Munich Metropolitan Region, Île-de-France, and San Francisco Bay Area) have been routed using the UAM-extension for the multi-agent transport simulation (MATSim) to calculate congested trip travel times for each trip’s original mode—i.e., car or public transport (PT)—and UAM. The resulting travel times are compared and allow the deduction of potential UAM trip shares under varying UAM properties, such as the number of stations, total process time, and cruise flight speed. Under base-case conditions, the share of motorized trips for which UAM would reduce the travel times ranges between 3% and 13% across the three scenarios. Process times and number of stations heavily influence these potential shares, where the vast majority of UAM trips would be below 50 km in range. Compared to car usage, UAM’s (base case) travel times are estimated to be competitive beyond the range of a 50-minute car ride and are less than half as much influenced by congestion.

scholarly journals Adapting to sea level rise: Emerging governance issues in the San Francisco Bay Region

2018 ◽  
Author(s):  
Pedro J. Pinto ◽  
G. Mathias Kondolf ◽  
Pun Lok Raymond Wong
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
San Francisco ◽  
Urban Areas ◽  
Path Dependence ◽  
Large Scale ◽  
San Francisco Bay ◽  
Metropolitan Region ◽  
Environmental Benefit ◽  
Formidable Challenge

San Francisco Bay, the largest estuary on the Pacific Coast of North America, is heavily encroached by a metropolitan region with over 7 million inhabitants. Urban development and infrastructure, much of which built over landfill and at the cost of former baylands, were placed at very low elevations. Sea-level rise (SLR) poses a formidable challenge to these highly exposed urban areas and already stressed natural systems. “Green”, or ecosystem-based, adaptation is already on the way around the Bay. Large scale wetland restoration projects have already been concluded, and further action now often requires articulation with the reinforcement of flood defense structures, given the level of urban encroachment. While levee setback, or removal, would provide greater environmental benefit, the need to protect urban areas and infrastructure has led to the trial of ingenious solutions for promoting wetland resilience while upgrading the level of protection granted by levees.We analyzed the Bay’s environmental governance and planning structure, through direct observation, interviews with stakeholders, and study of planning documents and projects. We present two cases where actual implementation of SLR adaptation has led, or may lead to, the need to revise standards & practices or to make uneasy choices between conflicting public interests.Among the region’s stakeholders, there is an increasing awareness of the risks related to SLR, but the institutional arrangements are complex, and communication between the different public agencies/departments is not always as streamlined as it could be. Some agencies and departments need to adapt their procedures in order to remove institutional barriers to adaptation, but path dependence is an obstacle. There is evidence that more frank and regular communication between public actors is needed. It also emphasizes the benefits of a coordination of efforts and strategies, something that was eroded in the transition from government-led policies to a new paradigm of local-based adaptive governance.

scholarly journals Singing in a silent spring: Birds respond to a half-century soundscape reversion during the COVID-19 shutdown

Science ◽  
2020 ◽  
Vol 370 (6516) ◽  
pp. 575-579 ◽  
Author(s):  
Elizabeth P. Derryberry ◽  
Jennifer N. Phillips ◽  
Graham E. Derryberry ◽  
Michael J. Blum ◽  
David Luther
Keyword(s):  
San Francisco ◽  
Urban Areas ◽  
Motor Vehicle ◽  
Noise Pollution ◽  
Anthropogenic Pressures ◽  
Behavioral Traits ◽  
Bay Area ◽  
Survival And Reproduction ◽  
Acoustic Space ◽  
Favorable Conditions

Actions taken to control the coronavirus disease 2019 (COVID-19) pandemic have conspicuously reduced motor vehicle traffic, potentially alleviating auditory pressures on animals that rely on sound for survival and reproduction. Here, by comparing soundscapes and songs across the San Francisco Bay Area before and during the recent statewide shutdown, we evaluated whether a common songbird responsively exploited newly emptied acoustic space. We show that noise levels in urban areas were substantially lower during the shutdown, characteristic of traffic in the mid-1950s. We also show that birds responded by producing higher performance songs at lower amplitudes, effectively maximizing communication distance and salience. These findings illustrate that behavioral traits can change rapidly in response to newly favorable conditions, indicating an inherent resilience to long-standing anthropogenic pressures such as noise pollution.

Analysis of Freeway Improvements for Express Bus Service

2005 ◽  
Vol 1925 (1) ◽  
pp. 256-264 ◽  
Author(s):  
Christopher R. Cherry ◽  
Eric Tang ◽  
Elizabeth Deakin ◽  
Alexander Skabardonis
Keyword(s):  
San Francisco ◽  
Operations Management ◽  
Urban Areas ◽  
Traffic Simulation ◽  
Simulation Models ◽  
Bay Area ◽  
Bus Service ◽  
Preliminary Planning ◽  
Hov Lanes ◽  
Scenario Testing

In many urban areas, high-occupancy vehicle (HOV) lanes have been provided to permit carpools and express buses to bypass congestion and offer a significant travel time advantage to commuters willing to share a ride or take transit. In many locations, however, HOV lanes are incomplete because of difficulties in securing right-of-way or funding. In other locations, because existing HOV lanes are underutilized, express buses are undersubscribed, or both, questions about their value arise. In this research it is shown how a PARAMICS microscopic traffic simulation model can be used to analyze proposed HOV lanes and their effects on express bus operation along an urban freeway corridor. A PARAMICS application is developed for Interstate 580 in the San Francisco Bay Area and used to test alternative ways of providing HOV lanes. The performance of the corridor is evaluated under plausible scenarios of traffic growth. Traffic simulation models are usually used for detailed operations management. The case study shows that traffic simulation can be an effective preliminary planning and scenario testing tool for evaluating the likely performance of an infrastructure or operations improvement on express bus service.

scholarly journals Regionalization for urban air mobility application in metropolitan areas: case studies in San Francisco and New York

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Namwoo Kim ◽  
Yoonjin Yoon
Keyword(s):  
New York ◽  
San Francisco ◽  
Correspondence Analysis ◽  
Urban Space ◽  
Urban Areas ◽  
Spatial Information ◽  
Economic Feasibility ◽  
Urban Air ◽  
Target Area ◽  
Demand Prediction

In a new era of mobility where the transportation of persons or goods via flying vehicles over urban areas has garnered great interest in its application in urban space. With the anticipated utilization of sUAS in urban airspace, a multi-dimensional understanding of urban space is essential. As a first step to assess the feasibility of Urban Air Mobility (UAM) in urban areas, we conduct regionalization and correspondence analysis in highly urbanized areas – San Francisco, CA and Manhattan, NY – by incorporating population dataset and urban 3D airspace to delineate the regional boundaries. Regionalization is carried out using graph-based clustering technique called SKATER (Spatial ‘K’luster Analysis by Tree Edge Removal) to group the regions having similar characteristics and address the compound effect of both population and spatial information. By classifying the regions into five categories through correspondence analysis, the operational and economic feasibility of each region is evaluated. The results provide the region maps of each city with the most and least attractive regions for UAM application with the temporal notion, whether the clusters are daytime-intensive or nighttime-intensive areas. The outcomes have several unique information that can benefit drone delivery target area identification, landing location identification, demand prediction. Our approach can contribute to providing a useful basis for management for UAM in urban areas as well as the process of regulating airspace use.

scholarly journals Evaluation of Road Infrastructure Alternatives Through a Saving Gradient in Travel Times. Case Study: Second Connection Villamaría-Manizales, Colombia

2018 ◽  
Vol 12 (8) ◽  
pp. 103
Author(s):  
Diego Alexander Escobar ◽  
Santiago Cardona ◽  
Carlos Alberto Moncada
Keyword(s):  
Urban Areas ◽  
Social Economic ◽  
Master Plan ◽  
Travel Times ◽  
Investment Projects ◽  
Sustained Development ◽  
Geographical Barrier ◽  
Travel Time Savings ◽  
Time Savings

In the last century, the migration of people from rural to urban areas of cities has generated a set of dynamics in different sectors such as social, economic, educational that have led cities to collaborate among them, generating a constant synergy in order to obtain a sustained development in multiple aspects. In this sense, Manizales as the capital of the department of Caldas in Colombia has generated a conurbation with the nearest neighboring municipality, Villamaría reaching a combined population of 419 943. Although this synergy has taken place for several decades, these municipalities only have a place of connection, because they are separated by a geographical barrier, the Chinchiná River. This connection has had clear connection problems, due to the high flow of vehicles that move between both municipalities, so it is essential to project a second connection, to further boost mobility among its inhabitants. For this reason, in this research four (4) alternatives of connection are proposed, according to the suggestions of the Manizales 2017 Mobility Master Plan, through the calculation of the global average accessibility and the quantification of the gradient of savings generated in the average times of trip, based on the current situation of both cities. The results show which is the alternative that benefits population the most in terms of travel time savings, although three of them generate considerable savings and only one is discarded because it benefits a smaller number of inhabitants in very low percentages of savings compared to the others. The evaluation of infrastructure alternatives through the gradient of savings in travel times is useful to determine the best options in the pre-feasibility phase of investment projects in the transport area.

scholarly journals URBAN STRUCTURE OF THE SAN FRANCISCO BAY AREA IN THE CONTEXT OF FORMATION OF A NEW TYPE OF URBAN FABRIC

World Science ◽  
2018 ◽  
Vol 1 (10(38)) ◽  
pp. 4-9
Author(s):  
Andriy Pavliv
Keyword(s):  
San Francisco ◽  
Urban Areas ◽  
San Francisco Bay ◽  
San Francisco Bay Area ◽  
Rapid Development ◽  
Urban Structure ◽  
Urban Forms ◽  
Bay Area ◽  
New Type ◽  
Post Industrial

The purpose of this article is to outline the changes and phenomena within the urban planning structure of the San Francisco bay area, which can be interpreted as impulses associated with the emergence of new post-industrial urban forms. Formation of the theory of impulse modeling of an urban organism requires not only theoretical generalizations and study of the material relating to the peculiarities of the post-industrial (informational) era, but also the search for practical phenomena associated with the rapid development of certain urban areas. At the same time, such development should not be confused with the concept of polycentrism, which was formed during the period of modernism.

scholarly journals Local- and regional-scale racial and ethnic disparities in air pollution determined by long-term mobile monitoring

2021 ◽  
Vol 118 (37) ◽  
pp. e2109249118
Author(s):  
Sarah E. Chambliss ◽  
Carlos P.R. Pinon ◽  
Kyle P. Messier ◽  
Brian LaFranchi ◽  
Crystal Romeo Upperman ◽  
...  
Keyword(s):  
Air Pollution ◽  
San Francisco ◽  
Ultrafine Particles ◽  
Spatial Scales ◽  
Regional Scale ◽  
Ethnic Disparities ◽  
Metropolitan Region ◽  
Bay Area ◽  
Population Average ◽  
Black Populations

Disparity in air pollution exposure arises from variation at multiple spatial scales: along urban-to-rural gradients, between individual cities within a metropolitan region, within individual neighborhoods, and between city blocks. Here, we improve on existing capabilities to systematically compare urban variation at several scales, from hyperlocal (<100 m) to regional (>10 km), and to assess consequences for outdoor air pollution experienced by residents of different races and ethnicities, by creating a set of uniquely extensive and high-resolution observations of spatially variable pollutants: NO, NO2, black carbon (BC), and ultrafine particles (UFP). We conducted full-coverage monitoring of a wide sample of urban and suburban neighborhoods (93 km2 and 450,000 residents) in four counties of the San Francisco Bay Area using Google Street View cars equipped with the Aclima mobile platform. Comparing scales of variation across the sampled population, greater differences arise from localized pollution gradients for BC and NO (pollutants dominated by primary sources) and from regional gradients for UFP and NO2 (pollutants dominated by secondary contributions). Median concentrations of UFP, NO, and NO2 are, for Hispanic and Black populations, 8 to 30% higher than the population average; for White populations, average exposures to these pollutants are 9 to 14% lower than the population average. Systematic racial/ethnic disparities are influenced by regional concentration gradients due to sharp contrasts in demographic composition among cities and urban districts, while within-group extremes arise from local peaks. Our results illustrate how detailed and extensive fine-scale pollution observations can add new insights about differences and disparities in air pollution exposures at the population scale.

scholarly journals Open-Source Food: Nutrition, Toxicology, and Availability of Wild Edible Greens in the East Bay

2018 ◽  
Author(s):  
Philip B. Stark ◽  
Daphne Miller ◽  
Thomas J. Carlson ◽  
Kristen Rasmussen de Vasquez
Keyword(s):  
Heavy Metals ◽  
San Francisco ◽  
Urban Areas ◽  
Tap Water ◽  
Leafy Greens ◽  
Bay Area ◽  
Lead And Cadmium ◽  
Nutrient Density ◽  
Mixed Use ◽  
East Bay

AbstractSignificanceForaged leafy greens are consumed around the globe, including in urban areas, and may play a larger role when food is scarce or expensive. It is thus important to assess the safety and nutritional value of wild greens foraged in urban environments.MethodsField observations, soil tests, and nutritional and toxicology tests on plant tissue were conducted for three sites, each roughly 9 square blocks, in disadvantaged neighborhoods in the East San Francisco Bay Area in 2014–2015. The sites included mixed-use areas and areas with high vehicle traffic.ResultsEdible wild greens were abundant, even during record droughts. Soil at some survey sites had elevated concentrations of lead and cadmium, but tissue tests suggest that rinsed greens of the tested species are safe to eat. Daily consumption of standard servings comprise less than the EPA reference doses of lead, cadmium, and other heavy metals. Pesticides, glyphosate, and PCBs were below detection limits.The nutrient density of 6 abundant species compared favorably to that of the most nutritious domesticated leafy greens.ConclusionsWild edible greens harvested in industrial, mixed-use, and high-traffic urban areas in the San Francisco East Bay area are abundant and highly nutritious. Even grown in soils with elevated levels of heavy metals, tested species were safe to eat after rinsing in tap water. This does not mean that all edible greens growing in contaminated soil are safe to eat—tests on more species, in more locations, and over a broader range of soil chemistry are needed to determine what is generally safe and what is not. But it does suggest that wild greens could contribute to nutrition, food security, and sustainability in urban ecosystems. Current laws, regulations, and public-health guidance that forbid or discourage foraging on public lands, including urban areas, should be revisited.

scholarly journals Local and Regional-Scale Racial and Ethnic Disparities in Air Pollution Determined by Long-Term Mobile Monitoring

2021 ◽  
Author(s):  
Sarah Chambliss ◽  
Carlos Pinon ◽  
Kyle Messier ◽  
Brian LaFranchi ◽  
Crystal Upperman ◽  
...  
Keyword(s):  
Air Pollution ◽  
San Francisco ◽  
Ultrafine Particles ◽  
Spatial Scales ◽  
Regional Scale ◽  
Ethnic Disparities ◽  
Metropolitan Region ◽  
Bay Area ◽  
Population Average ◽  
Black Populations

<p>Disparity in air pollution exposure arises from variation at multiple spatial scales: along urban-to-rural gradients, between individual cities within a metropolitan region, within individual neighborhoods, and between city blocks. Here, we improve on existing capabilities to systematically compare urban variation at several scales, from hyperlocal (<100m) to regional (>10km), and to assess consequences for the outdoor air pollution experienced by residents of different races and ethnicities, by creating a set of uniquely extensive and high-resolution observations of spatially-variable pollutants: NO, NO<sub>2</sub>, black carbon (BC), and ultrafine particles (UFP). We conducted full coverage monitoring of a wide sample of urban and suburban neighborhoods (93 km<sup>2</sup>, 450,000 residents) in four counties of the San Francisco Bay Area using Google Street View cars. Comparing scales of variation across the sampled population, greater differences arise from localized pollution gradients for BC and NO (pollutants dominated by primary sources) and from regional gradients for UFP and NO<sub>2</sub> (pollutants dominated by secondary contributions). Median concentrations of UFP, NO, and NO<sub>2</sub> are, for Hispanic and Black populations, 8%-30% higher than the population average; for white populations, average exposures to the same pollutants are 9%-14% lower than the population average. Systematic racial/ethnic disparities are strongly affected by regional differences in background concentrations due to sharp contrasts in demographic composition among cities and urban districts, while within-group extremes arise from local peaks. Our results illustrate how detailed and extensive fine-scale pollution observations can add new insights about differences and disparities in air pollution exposures at the population scale. </p>

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