Sustainability

Potential Greenhouse Gas Emission Reductions from Optimizing Urban Transit Networks

Madanat, Samer
Horvath, Arpad
Mao, Chao
Cheng, Han
2016

Public transit systems with efficient designs and operating plans can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but many current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. Previous studies have demonstrated in an idealized...

Reducing Emissions through Monitoring and Predictive Modeling of Gate Operations of Idle Aircraft: A Case Study on San Francisco International Airport

Rakas, Jasenka, PhD
Achatz Antonelli, Pietro
Walia, Chanan
Rouzbahani, Parham
Gikas, George
2023

The use of airport gate electrification infrastructure in the form of ground power (GP) and preconditioned air (PCA) systems can reduce energy and maintenance costs, emissions, and health risks by limiting the use of aircraft auxiliary power unit (APU) engines at the gate. However, their benefits can only be gained when they are actually being used; otherwise, pilots keep APUs on to fulfill their aircraft’s demands for electrical power and air conditioning. GP and PCA systems require a large initial infrastructure investment to increase energy efficiency, and they are installed with the...

Environmental Justice & Transportation: A Citizen's Handbook

Cairns, Shannon
Greig, Jessica
Wachs, Martin
2003

Environmental justice is an increasingly important element of policy making in transportation. It is not specific to any mode of transportation, particular community, or single policy issue. It is fundamentally about fairness toward the disadvantaged and often addresses the exclusion of racial and ethnic minorities from decision making. The federal government has identified environmental justice as an important goal in transportation, and local and regional governments must incorporate environmental justice into transportation programs. Because ideas about justice differ between...

Enriching Sustainable Transport Decisions: Inputs from Operations Research and the Management Sciences

Wellar, Barry
Garrison, William
2009

Findings from the 2008-2009 Transport Canada project, Methodologies for Identifying and Ranking Sustainable Transport Practices in Urban Regions (Wellar, 2008d) reveal that the research methodologies, methods, and techniques from a number of disciplines apply to the process of making decisions about sustainable transport practices. Evidence in that regard is provided by: 1) the results of keyword-based literature searches; 2) the responses of municipal governments to a survey on the methodologies, methods, and techniques that are used; and 3), the commentaries of experts on the methods and...

Historical Transportation Development

Garrison, William L.
2003

The main tasks for this overview of transportation development are the provision and interpretation of information on the unfolding of the transportation systems. What have been the processes at work? What explains the similarities and differences from here to there and among systems? Big questions! But they are eased by ways systems are products of experiences, as will be seen when the paragraphs immediately following summarize early experiences. Life support systems, sustainability, and social development topics will be mentioned. After examining their immediate precursors, the...

Universal Basic Mobility Pilots in Oakland and Los Angeles: Striking a Balance Between Accessibility and Sustainability

Romero, Sandra, MCP
2024

The Universal Basic Mobility (UBM) pilots in Oakland and Los Angeles, launched in 2021, were innovative initiatives to address transportation equity and access issues in historically underserved communities. These experimental programs examined the impact of providing flexible transportation benefits to low-income residents. However, the current program designs fall short of achieving accessibility and sustainability objectives. Instead, they serve as initial steps in exploring UBM as a potential transportation equity strategy. The report explores the motivation behind local agencies...

High Accuracy Location Based Services CostBenefit Study: Final Report

Goodliss, Adam
Manasseh, Christian
Ekambaram, Venkatesan
Sengupta, Raja
Kanafani, Adib
Ramchandran, Kannan
2011

This report presents a benefit and cost study of a Cooperative High‐Accuracy LOcation (C‐HALO) service. A High Accuracy Location service should be ubiquitous and reliable as the GPS constellation. A survey of the literature on location services reveals a body of work on the benefits of a high accuracy location service. Focusing on road travel, benefits are estimated to be between $160-$320 billion dollars over slightly more than 20 years. The benefits arise from smoother traffic flow on the roads leading to reduced travel delays, and fewer accidents leading to reduced injuries and saved...

How Well Do New K-12 Public School Sites in California Incorporate Mitigation Measures Known to Reduce Vehicle Miles Traveled?

Vincent, Jeffrey M., PhD
Maves, Sydney
Thompson, Amy
2022

California law (SB 743) requires school districts to measure the impact of school construction on the production of greenhouse gas emissions (GHG) and identify feasible mitigation measures that eliminate or substantially reduce the number of vehicle miles traveled (VMT) generated. This study analyzes 301 new schools constructed between 2008-2018 with respect to four VMT mitigation measures identified by the Governor’s Office of Planning and Research (OPR) known to minimize VMT (proximity to high quality transit areas, proximity to roads with bicycle facilities, walkability scores, and...

Hydrogen Can Have a Much Lower Carbon Intensity than Fossil Fuels But This Largely Depends on How It Is Produced and Distributed

Lipman, Timothy, PhD
Horvath, Arpad, PhD
Collins, Stephanie
Kendall, Allisa, PhD
Fulton, Lewis, PhD
Busch, Pablo
2022

As interest in hydrogen as an energy carrier has increased, the various ways that hydrogen is made are being categorized as “green,” “blue,” “gray,” and other colors in relation to their environmental impact. While these categorizations are somewhat useful to indicate the environmental and climate change impacts of different production pathways, they are not especially useful for policy making or industry decisionmaking purposes because they are subjective. For example, most definitions of green pathways for hydrogen production only include electrolysis from renewable electricity sources;...

Automated Vehicle Technology Has the Potential to Smooth Traffic Flow and Reduce Greenhouse Gas Emissions

Almatrudi, Sulaiman
Parvate, Kanaad
Rothchild, Daniel
Vijay, Upadhi
Jang, Kathy
Bayen, Alexandre
2022

In an ideal world, all cars along a congested roadway would travel at the same constant average speed; however, this is hardly the case. As soon as one driver brakes, trailing cars must also brake to compensate, leading to “stop and go” traffic waves. This unnecessary braking and accelerating increases fuel consumption (and greenhouse gas emissions) by as much as 67 percent.1 Fortunately, automated vehicles (AVs) — even Level 2 AVs2 which are commercially available today — have the potential to mitigate this problem. By accelerating less than a human would, an AV with flow smoothing...