blog

What Happened to Stockton's First Asian Enclaves?: How the City’s Chinatown, Japantown, and Little Manila Were Razed in the Name of "Progress"

Areas of Expertise

Safety, Public Health, & Mobility Justice Travel Behavior, Land Use, & the Built Environment

research report

Risk Assessment for Security Threats and Vulnerabilities of Autonomous Vehicles

Publication Date

April 1, 2024

Author(s)

Trishna Chakraborty, Alfred Chen

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data Safety, Public Health, & Mobility Justice

Abstract

Autonomous vehicles (AVs) heavily rely on machine learning-based perception models to accurately interpret their surroundings. However, these crucial perception components are vulnerable to a range of malicious attacks. Even though individual attacks can be highly successful, the actual security risks such attacks can pose to daily life are unclear. Various factors, such as lack of stealthiness, cost-effectiveness, and ease of deployment, can deter potential attackers from employing certain attacks, thereby reducing the actual risk. This research report presents the first quantitative risk assessment for physical adversarial attacks on AVs. The specific focus is on attacks on an AV’s perception components due to their highly critical function and representation in existing research. The report defines the daily-life risk as the likelihood that a given type of attack will be employed in real life and the authors develop a problem-specific risk scoring system and accompanying metrics. The report provides an initial evaluation of the proposed risk assessment method for all the reported attacks on AVs from 2017 to 2023, and quantitatively ranks the daily-life risks posed by each of eight different categories of attacks and find three attacks with the highest risks: 2D printed images, 2D patches, and coated camouflage stickers, which deserve more focused attention for potential future mitigation strategy development and policy making.

policy brief

Pathways to Autonomy: Supporting Youth Independent Mobility in Westlake, Los Angeles

Publication Date

October 23, 2023

Author(s)

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Each day, youth in Los Angeles venture out on their own to move to and from home, school, and after-school activities. Their travels represent important pathways to autonomy, agency, and urban citizenship, which a city can support with safe, pleasant paths that offer reassuring familiarity and opportunities for socializing.

research report

Fuel Portfolio Scenario Modeling (FPSM) of 2030 and 2035 Low Carbon Fuel Standard Targets in California

Publication Date

November 1, 2023

Author(s)

Colin Murphy, Jin Wook Ro, Qian Wang

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

The Low Carbon Fuel Standard (LCFS) plays a critical role in California’s efforts to reduce greenhouse gas (GHG) and air pollutant emissions from transportation. The LCFS incentivizes the use of fuels with lower life cycle greenhouse gas emissions by using a credit market mechanism to provide incentives for low-carbon fuels, using revenue generated by charges applied to high-carbon ones. Maintaining an approximate balance between LCFS credit and deficit supplies helps support a stable LCFS credit price and the broader transition to low-carbon transportation. The Fuel Portfolio Scenario Model, presented here, evaluates bottom-up fuel supply and LCFS compliance to inform LCFS policy decisions. The research team considered two key fuel demand scenarios: (1) the Low Carbon Transportation scenario, reflecting the expected transition to low-carbon transportation in California over the next 15 years, and (2) the Driving to Zero scenario, featuring a significantly higher consumption of petroleum gasoline. In both scenarios, 2030 LCFS targets around 30% resulting in a near-balance between credits and deficits, with some banked credits remaining. Several additional scenarios were modeled to explore the impact of target trajectory timing, alternate post-2030 targets, greater biofuel use, and other parameters. This fuel portfolio scenario modeling work can meaningfully inform policy development.

research report

Pathways to Autonomy: Supporting Youth Independent Mobility in Westlake, Los Angeles

Publication Date

October 23, 2023

Author(s)

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

In this study, the research paper uses the concept of “sidewalk ecologies” to highlight the complex interaction between spatially situated social and material features of sidewalks that influence youth mobility. The research team uses a range of interdisciplinary strategies, emphasizing youth-centered research methods and mapping to capture a rich portrait of the independent travel experiences, perceptions, and ideas of youth, in their own voices. This research was conducted in partnership with Heart of Los Angeles (HOLA), a community-based organization in Westlake that provides after-school programming to thousands of neighborhood youths, and yielded important findings.

published journal article

Evaluating Road Resilience to Wildfires: Case Studies of Camp and Carr Fires

Publication Date

August 31, 2023

Author(s)

Somayeh Nassiri, Ali A. Butt, Ali Zarei, Changmo Kim, Rongzong Wu, Jeremy Lea

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience

Abstract

Between 2017 and 2018, California experienced four devastating fires, including the Camp and Carr Fires. After fires, road infrastructure is crucial for safe removal of hazardous materials and waste to landfills and recycling facilities. Despite the critical role of pavements in this process, there has been little quantitative evaluation of the potential damage to pavements from truck traffic for debris removal. To address this knowledge gap, data on truck trip numbers and debris tonnage following the Camp and Carr Fires were used to calculate changes in equivalent single axle loads and traffic index over the pavement’s design life (the age at which reconstruction would be considered). Simulations were conducted on existing pavement structures to assess potential additional damage based on increased traffic indices. Pavement structural design simulations showed that out of the nine studied highways, one exhibited a reduction in cracking life of about two years from debris removal operations. However, fatigue cracking was significantly accelerated for Skyway, the major road in the Town of Paradise, failing 14.3 years before its design life. A methodology similar to the one presented in this study can be adopted in debris management planning to strategically avoid vulnerable pavements and minimize damage to the highway network.

research report

Evaluating Road Resilience to Wildfires: Case Studies of Camp and Carr Fires

Publication Date

December 1, 2023

Author(s)

Somayeh Nassiri, Ali A. Butt, Ali Zarei, Changmo Kim, Rongzong Wu, Jeremy Lea

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience

Abstract

Between 2017 and 2018, California experienced four devastating fires, including the Camp and Carr Fires. After fires, road infrastructure is crucial for safe removal of hazardous materials and waste to landfills and recycling facilities. Despite the critical role of pavements in this process, there has been little quantitative evaluation of the potential damage to pavements fromtruck traffic for debris removal. To address this knowledge gap, data on truck trip numbers and debris tonnage following the Camp and Carr Fires were used to calculate changes in equivalent single axle loads and traffic index over the pavement’s design life(the age at which reconstruction would be considered). Simulations were conducted on existing pavement structures to assess potential additional damage based on increased traffic indices. Pavement structural design simulations showed that out of the nine studied highways, one exhibited a reduction in cracking life of about two years from debris removal operations. However, fatigue cracking was significantly accelerated for Skyway, the major road in the Town of Paradise, failing 14.3 years before its design life. A methodology similar to the one presented in this study can be adopted in debris management planning to strategically avoid vulnerable pavements and minimize damage to the highway network

research report

Effects of Road Collisions on the Travel Behavior of Vulnerable Groups: Expert Interview Findings

Publication Date

April 1, 2024

Author(s)

Jesus Barajas, Prashanth Venkataram, Md. Musfiqur Rahman Bhuiya

Areas of Expertise

Safety, Public Health, & Mobility Justice Travel Behavior, Land Use, & the Built Environment

Abstract

The research team interviewed eight subject-matter experts in California in 2023 to understand how travel behavior and priorities may change in response to direct experience with road collisions. Experts represented a variety of perspectives, including medical doctors, advocates for active transportation safety, and advocates for people with disabilities. Their diverse specialties enabled us to capture a variety of concerns without triggering emotionally sensitive areas for people who have directly experienced road collisions. These experts identified common themes, including mental stress from the prospect of returning to driving—especially on freeways, lesser incidence of long-term changes in travel modes after experiencing a collision, dependence on others for rides in private vehicles, and changing routes or times of day of travel when traveling independently. These experts also explained how people’s mode choices are also affected by general concerns about collisions in the news more than by specific personal experiences with near misses. Interview subjects’ spoke of more specific concerns as well. These included but were not limited to, bicyclists using sidewalks instead of bike lanes when both are present, feeling stigmatized from using public transit or paratransit after experiencing a collision, and concerns with motorists treating bicyclists badly. These initial interviews clarify areas of focus and methodology for future qualitative and quantitative studies on the intersection of transportation safety and travel behavior change, particularly as they involve people who have directly experienced road collisions.

published journal article

Emissions of Electric Vehicles in California’s Transition to Carbon Neutrality

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

California has many activities targeting specific sectors to mitigate climate change. This study models several scenarios of future electric vehicle emissions in the state and explores untapped policy opportunities for interactions between sectors, specifically between the transportation and electricity grid. As electric vehicles become more prevalent, their impact on the electricity grid is directly related to the aggregate patterns of vehicle charging—even without vehicle-to-grid services, shifting of charging patterns can be a potentially important resource to alleviate issues such as renewable intermittency. This study involved the creation of a model to predict the potential emissions benefits of managed vs. unmanaged charging. The study finds that the lion’s share of emissions reduction in the light-duty transportation sector in California comes from electrification, with a cumulative 1 billion tons of CO2 reduction through 2045. This figure represents a decrease of about 4 tons CO2/capita/year from the average operation of Californian passenger vehicles in 2020 to about 40 kg CO2/capita/year in 2045. Decarbonization of the current grid leads to an additional savings of 125 million tons of CO2 over the same time period. As the state moves towards these objectives through existing (and potential future) policies, additional policies to exploit synergies between transportation electrification and grid decarbonization could reduce cumulative emissions by another 10 million tons of CO2.

research report

An Integrated Corridor Management for Connected Vehicles and Park and Ride Structures using Deep Reinforcement Learning

Publication Date

August 16, 2023

Author(s)

Mohamad Habib Fakih, Mohammad Abdullah Al Faruque, Mohanad Odema, Tyler Zhang, Yasmin Moghaddas

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Intelligent Transportation Systems, Emerging Technologies, & Big Data

Abstract

The upcoming Connected Vehicles (CV) technology shows great promise in effectively managing traffic congestion and enhancing mobility for users along transportation corridors. Data analysis powered by sensors in Connected Vehicles allows us to implement optimized traffic management strategies optimizing the efficiency of transportation infrastructure resources. In this study, the research team introduces a novel Integrated Corridor Management (ICM) methodology, which integrates underutilized Park-And-Ride (PAR) facilities into the global optimization strategy. To achieve this, the team uses vehicle-to-infrastructure (V2I) communication protocols, namely basic safety messages (BSM) and traveler information messages (TIM) to help gather downstream traffic information and share park and ride advisories with upstream traffic, respectively. Next, the team develops a model that assesses potential delays experienced by vehicles in the corridor. Based on this model, the research team employs a novel centralized deep reinforcement learning (DRL) solution to control the timing and content of these messages. The ultimate goal is to maximize throughput, minimize carbon emissions, and reduce travel time effectively. To evaluate the Integrated Corridor Management strategy, the paper includes simulations on a realistic model of Interstate 5 using the Veins simulation software. The deep reinforcement learning agent converges to a strategy that marginally improves throughput, travel speed, and freeway travel time, at the cost of a slightly higher carbon footprint.