Modeling Framework for Estimating Emissions in Large Urban Areas

1997 ◽  
Vol 1587 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Alexander Skabardonis
Keyword(s):  
San Francisco ◽  
Urban Areas ◽  
Travel Demand ◽  
Planning System ◽  
Area Network ◽  
Modeling Framework ◽  
Driving Mode ◽  
Bay Area ◽  
Demand Models ◽  
Vehicle Activity

A modeling framework has been developed to produce detailed emission inventories for large urban areas. Relationships were developed between the time spent in each driving mode (cruise, acceleration, deceleration, and idle) and basic link characteristics based on simulations of selected real-world surface street networks and freeway sections using the TRAF-NETSIM and INTRAS microscopic models, supplemented by field data. These relationships were then incorporated into a specially written computer program as a postprocessor to the Urban Transportation Planning System type of four-step travel demand models. The integrated model was successfully applied to the 1,120-zone Metropolitan Transportation Commission San Francisco Bay Area network to generate vehicle activity estimates.

Developing Consistent Travel Demand Model Systems as a Building Block for Cooperative Planning: Case Study of San Francisco Bay Area

1997 ◽  
Vol 1606 (1) ◽  
pp. 124-131
Author(s):  
Valerie R. Knepper
Keyword(s):  
San Francisco ◽  
Travel Demand ◽  
San Francisco Bay ◽  
San Francisco Bay Area ◽  
Model Systems ◽  
Demand Model ◽  
Bay Area ◽  
Demand Models ◽  
Cooperative Planning ◽  
Travel Demand Model

The San Francisco Bay Area is characterized by a diverse mixture of urban, suburban, and rural development patterns; multiple jurisdictions with local, state, and federal responsibilities; and a multiplicity of transportation system planners, owners, and operators. The Metropolitan Transportation Commission (MTC), the metropolitan planning organization for the region, is responsible for coordinating transportation for the nine-county region and has a sophisticated set of travel-demand models. California established county-level congestion management programs in 1990, including a requirement for travel-demand model consistency with the regional model. Coordination of the multiple travel-demand model systems that proliferated in the region thus became a significant issue. The cooperative planning approach promoted by MTC through the Bay Area Partnership, and the passage of the Intermodal Surface Transportation Efficiency Act, gave additional impetus to integrating transportation information from multiple agencies, including travel-demand model information. The development of an approach to establishing consistency between the travel-demand model systems in the San Francisco Bay Area is described, as are the immediate and subsequent strategies undertaken.

scholarly journals Continuous Time Representation and Modeling Framework for Analysis of Nonworker Activity-Travel Patterns: Tour and Episode Attributes

2003 ◽  
Vol 1831 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Rajul Misra ◽  
Chandra R. Bhat ◽  
Sivaramakrishnan Srinivasan
Keyword(s):  
San Francisco ◽  
Continuous Time ◽  
San Francisco Bay Area ◽  
Location Choice ◽  
Travel Patterns ◽  
Modeling Framework ◽  
Time Representation ◽  
Bay Area ◽  
Activity Duration ◽  
Travel Diary

A set of four econometric models is presented to examine the tour and episode-related attributes (specifically, mode choice, activity duration, travel times, and location choice) of the activity-travel patterns of non-workers, as a sequel to an earlier work by Bhat and Misra (2001), which presented a comprehensive continuous-time framework for representation and analysis of the activity-travel choices of nonworkers. Detailed descriptions of the first two components of the modeling framework related to the number and sequence of activity episodes are also presented. The proposed models using activity-travel data from the 1990 San Francisco Bay Area travel diary survey are estimated.

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.

Health Impact Assessment of Connected and Autonomous Vehicles in San Francisco, Bay Area

2020 ◽  
Vol 2674 (10) ◽  
pp. 898-916
Author(s):  
Elham Pourrahmani ◽  
Miguel Jaller ◽  
Neil Maizlish ◽  
Caroline Rodier
Keyword(s):  
Physical Activity ◽  
San Francisco ◽  
Autonomous Vehicles ◽  
Emission Reduction ◽  
Travel Demand ◽  
San Francisco Bay Area ◽  
Health Impact ◽  
Health Impacts ◽  
Bay Area ◽  
Life Years

This paper presents the potential human health impacts from connected and autonomous vehicles (CAVs) in the San Francisco, Bay Area, U.S. The study concentrates on impacts derived from CAVs’ outcomes on travel demand, safety, and environmental emissions. The paper combines travel modeling practices, critical literature review, and the authors’ expert inference, to quantify the human health impacts using the Integrated Transport and Health Impacts Model (ITHIM). Specifically, ITHIM estimates impact considering changes in travel demand, level of physical activity, emissions, and safety features. This study estimates a 10% increase in car travel mileage and an 11% decrease in walk/bike trip mode share at the presence of CAVs; a 70%–90% crash reduction because of safer CAVs; and significant emission reduction by several CAV-enabled mechanisms such as eco-driving (over 30% CO2 emission reduction) and engine performance adjustment (over 20% CO2 emission reduction). The health impact assessments show significant opportunities for road traffic injury reductions (annual saving of more than 300 deaths and 14,000 life years). However, reduced physical activity because of the mode shift to the car could cause negative health outcomes (increased annual deaths and disability-adjusted life years (DALYs) by more than 30–60 and 700–900, respectively). A set of (active transport [AT] and vehicle electrification) scenarios were developed that could mitigate the potential health-related risks and evaluated their effectiveness. The results show enormous benefits from 50% increased travel-related physical activity which offset the CAV health drawbacks and generates additional benefits by preventing premature deaths and saving life years.

Defining the conservation potential for San Francisco's 28 wholesale customers

2005 ◽  
Vol 5 (3-4) ◽  
pp. 189-196
Author(s):  
E. Levin ◽  
M. Carlin ◽  
W.O. Maddaus ◽  
N. Sandkulla
Keyword(s):  
San Francisco ◽  
Water Conservation ◽  
Water Demand ◽  
The United States ◽  
Benefit Cost Analysis ◽  
Bay Area ◽  
Conservation Measures ◽  
Demand Models ◽  
The Individual ◽  
Benefit Cost

This paper documents the methodology and results of a comprehensive water demand and conservation study conducted in 2003 and 2004 under the direction of the San Francisco Public Utilities Commission (SFPUC) in conjunction with its 28 wholesale customers. These customers are represented by the Bay Area Water Supply and Conservation Agency (BAWSCA). The SFPUC supplies water to about 1.6 million people within the San Francisco Bay Area plus about 700,000 within the City of San Francisco itself. A detailed benefit-cost analysis was conducted using the Demand Side Management Least-Cost Planning Decision Support System (DSS) model for 32 conservation measures using the individual customers' DSS model. Thirty-year water savings, benefit–cost ratios, and the cost of water saved were computed for each measure. Based on compiling the results from the individual customer demand models, it was found that the current plumbing and appliance codes would reduce overall 2030 water demand by 7.8% and that packages of additional water conservation measures could reduce demands by an additional 2–6%, depending upon the level of conservation implemented. Overall, the study represents one of the largest water demand and conservation evaluation projects undertaken in the United States.

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 Validation of MCMC-Based Travel Simulation Framework Using Mobile Phone Data

2021 ◽  
Vol 2 ◽  
Author(s):  
Suxia Gong ◽  
Ismaïl Saadi ◽  
Jacques Teller ◽  
Mario Cools
Keyword(s):  
Mobile Phone ◽  
Travel Demand ◽  
Mobile Phone Data ◽  
Simulation Framework ◽  
Modeling Framework ◽  
Practical Applications ◽  
Mobility Data ◽  
Demand Models ◽  
The Difference ◽  
Using Data

An essential step in agent-based travel demand models is the characterization of the population, including transport-related attributes. This study looks deep into various mobility data in the province of Liège, Belgium. Based on the data stemming from the 2010 Belgian HTS, that is, BELDAM, a Markov chain Monte Carlo (MCMC) sampling method combined with a cross-validation process is used to generate sociodemographic attributes and trip-based variables. Besides, representative micro-samples are calibrated using data about the population structure. As a critical part of travel demand modeling for practical applications in the real-world context, validation using various data sources can contribute to the modeling framework in different ways. The innovation in this study lies in the comparison of outputs of MCMC with mobile phone data. The difference between modeled and observed trip length distributions is studied to validate the simulation framework. The proposed framework infers trips with multiple attributes while preserving the traveler’s sociodemographics. We show that the framework effectively captures the behavioral complexity of travel choices. Moreover, we demonstrate mobile phone data’s potential to contribute to the reliability of travel demand models.

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.

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