Recent itsirvine_reports items

Benefits, Challenges, and Opportunities of Different Last-Mile Delivery Strategies

Wed, 5 Aug 2026 00:00:00 +0000

As online shopping nears its third decade, it is clear that its impacts on urban goods flow are profound. Increased freight traffic and related negative externalities such as greenhouse gas emissions and local air pollution can impede sustainability goals. In response, e-retailers are exploring innovative distribution strategies to enhance last-mile delivery sustainability and efficiency. They use urban consolidation centers with light-duty vehicles like electric vans and cargo bikes, establish alternative customer pickup points, and deploy crowdsourced delivery networks. Advanced technologies that may streamline deliveries, such as autonomous delivery robots and unmanned aerial vehicles, are being tested. University of California Davis and Irvine researchers have investigated these strategies under economic viability, environmental efficiency, and social equity frameworks. Different modeling approaches were implemented to evaluate last-mile network designs and the potential for...

Pathway to a Comeback: Student Transit Passes Can Drive Ridership and Equity in Post-Pandemic California

Wed, 15 Jul 2026 00:00:00 +0000

This study investigates free and reduced fare pass programs (FRFPs) for K-12, post-secondary, and college students across California since the COVID-19 pandemic and their role in ridership recovery. A survey of 67 transit agencies, including 34 with established FRFPs, indicates that most of them maintained their FRFPs between fiscal years 2018-2019 and 2022-2023, showcasing agencies' resilience despite financial uncertainty. LA Metro's GoPass enrolled over 241,000 students and generated 1.2 million monthly boardings, inspiring similar initiatives. Post-pandemic, K-12 FRFPs saw significant expansion, improved funding, and a surge in ridership across participating agencies. These findings underscore the positive influence of fare-based incentives on student mobility and attendance.

Exploring Transportation Mode Choice and Participation in LA Metro’s “GoPass” Program Among Los Angeles Community College Students

Thu, 2 Jul 2026 00:00:00 +0000

This research evaluates LA Metro's GoPass program—a fare-free transit initiative for K-12 and community college students—through asurvey of Los Angeles Community College District (LACCD) students. We investigated students' travel preferences through a discretechoice experiment, assessed GoPass awareness and participation impacts on transit use, and analyzed spatial and seasonal ridership patterns from TAP card records. GoPass participation increased transit use by 26 percentage points for school trips and 19 percentage points for discretionary trips, with greater benefits for socioeconomically disadvantaged students. Even students aware of GoPass but not participating showed a 5.8 percentage point increase in school-related transit use. However, 39% of eligible students were unaware of the program, and car access reduced transit use probability by 37 percentage points. The discrete choice experiment revealed students valued travel time savings at $27–$54 per hour and Wi-Fi availability...

Understanding Post-Pandemic Travel Behavior Patterns and Trends in California

Thu, 2 Jul 2026 00:00:00 +0000

The COVID-19 pandemic fundamentally reshaped global mobility, forcing a departure from previous travel norms. In California, initial declines in public transit and ride-hailing were accompanied by a surge in private vehicle interest and shifts to active travel. To assess whether spatial and temporal travel patterns shifted between 2019 and 2023, this study analyzed Performance Measurement System freeway data, regional transit boarding records, and spatial econometric modeling of Streetlight Insight data. The findings reveal a near-recovery of weekday freeway volumes and stable weekend patterns, yet an uneven transit recovery that favors buses over rail and weekends over weekdays. There was significant spatial dependence in active transportation; while the primary factors influencing walking and cycling remain consistent, their relative magnitudes have shifted. Ultimately, Californians’ choices of transportation modes are different after the pandemic than they were before it. Integrating...

E-shopping meets electrified self-driving: Impacts on the Number, Size, and Locations of Warehouses & Distribution Centers

Mon, 29 Jun 2026 00:00:00 +0000

This study shows that as freight transportation costs decline due to autonomous driving technology and online shopping increases, warehousing becomes more consolidated, the number and size of distribution centers increase, drayage truck mileage is reduced but delivery truck mileage increases, leading to a net mileage increase.

Zero-Emission Vehicle Transition in California’s Construction Industry

Mon, 29 Jun 2026 00:00:00 +0000

Although construction equipment generates 2% to 3% of total GHG emissions in California, the construction sector lags behind other industries for decarbonization, primarily due to the systemic challenges of delivering high-capacity electric power to temporary and remote jobsites. This study investigates the primary infrastructure, regulatory, and economic barriers to construction site electrification while exploring technological and policy solutions. Using a multi-faceted approach, we conducted a literature review, interviewed California Electric Load-Serving Entities, and analyzed emerging mobile charging technologies. Findings indicate that utility support varies by institutional model; municipal utilities often manage requests more efficiently than larger investor-owned utilities, which face complex regulatory hurdles. Key obstacles include local grid capacity limitations, long lead times and high costs for distribution upgrades, and high capital costs for electric machinery....

A Review of Pricing Strategies for Decarbonizing Transportation

Wed, 24 Jun 2026 00:00:00 +0000

California’s ability to achieve its climate and mobility goals depends on addressing the growing gap between transportation infrastructure needs and the declining effectiveness of traditional fuel tax revenues. As electric vehicle adoption rises, fuel efficiency improves, and demands for resilient, multimodal systems expand, new approaches to transportation funding and demand management are required. This paper examines a range of mobility pricing strategies—including tolling, managed lanes, congestion charges, vehicle-based fees and feebates, distance-based user charges, and parking pricing—to evaluate their potential for enhancing financial sustainability, reducing congestion, and internalizing the environmental and social costs of driving. Particular attention is given to dynamic pricing, which can flexibly manage demand for both road and parking space, and to distance-based charges that offer a more equitable and efficient alternative to fuel taxes. The analysis highlights...

Exploring Sensor Threats and Vulnerabilities in Intelligent Traffic Controllers

Thu, 11 Jun 2026 00:00:00 +0000

This study highlights that Inductive Loop Detectors (ILDs), sensors embedded into the pavement for traffic control, are concerningly vulnerable to novel cyber and physical attacks.

Co-Location of Light-Duty and Heavy-Duty Zero-Emission Vehicle Infrastructure to Promote a Resilient, Cost-Effective Fueling Network in California

Mon, 6 Apr 2026 00:00:00 +0000

This study examines whether co-locating stations for light-duty zero emission vehicles (ZEVs) with stations for heavy-duty ZEVs would increase network coverage and improve resiliency to help California achieve its targets for widespread ZEV adoption. The study separately models of siting light-and heavy-duty at the same locations vs. separate locations for (i) electric charging stations and (ii) hydrogen refueling stations. The results indicate electric charging stations in California are being used at only 13% of total capacity. Building out and optimizing the locations of light-duty electric vehicle stations will results in greater demand met and resiliency than will co-locating these at heavy-duty charging stations. On the other hand, co-location of hydrogen refueling stations for light duty vehicles at sites for heavy-duty vehicle stations may increase demand met, network resiliency, and adoption rates of light-and heavy-duty fuel cell electric vehicles. These adoption rates...

Vehicle Weight Safety Study Academic Report

Mon, 2 Mar 2026 00:00:00 +0000

The Vehicle Weight Safety Study provides supporting analysis for the California Transportation Commission’s study on therelationship between vehicle weight and road user injury and roadway degradation required by Assembly Bill (AB) 251, which was signed by the Governor in October 2023. To inform the work of the CTC, this report summarizes trends of road user injuries and fatalities in California and potential factors contributing to these trends (Chapter 2); summarizes trends in vehicle weight, size, and height for registered vehicles in California (Chapter 3); documents the landscape of policy solutions focused on vehicle size that might address California’s road user injuries and fatality challenge (Chapter 4); analyzes the impact of potential weight-based fees on consumer vehicle purchasing behavior (Chapter 5); and, analyzes the relationship between shifts in passenger vehicle weight and degradation of road infrastructure (Chapter 6).

Development of New Privacy-preserving Method for Traffic Data Collection and Analysis: The Bathtub Model Approach

Fri, 27 Feb 2026 00:00:00 +0000

Traditional data collection approaches present significant drawbacks in computational costs and limited privacy protection. This research evaluates the bathtub traffic flow model as a privacy-preserving alternative to traditional methods that require detailed network layouts and individual trip data. The study assesses the feasibility of the bathtub model through calibration and validation using Bluebikes data from Metro Boston, focusing on three key components: the unified relative space paradigm, conservation equations, and the generalized bathtub model. Results demonstrate that the unified relative space paradigm successfully integrates network trips by considering remaining trip distances, though the trip distance distribution exhibited a log-normal pattern rather than the time-independent negative exponential distribution in Vickrey's original bathtub model. Conservation equations for total trips and trip-miles traveled showed high accuracy, and the generalized bathtub model...

Reimagining Transportation as a Social Service to Build Resilience and Support Community Power

Wed, 29 Oct 2025 00:00:00 +0000

This study develops guidance for public transit agencies in Los Angeles, California to better prepare for hazards and address challenges, including climate and safety concerns. Using a community-based participatory research methodology in partnership with the local non-profit organization Climate Resolve, we conducted three listening sessions with 26community members involved with the Boyle Heights Arts Conservatory, a community-serving resilience hub that supports residents in accessing resources both during everyday conditions and extreme events, to explore theirexperiences related to public transit and how it could be better integrated with existing social systems to increase systems’ resilience to extreme weather disruptions. Based on several recurring themes drawn from the participants’ statements, we developed a framework named Cascading Vulnerabilities, Ascending Strengths to explore the connections between infrastructure systems’ vulnerabilities and strengths. We conclude...

Maximizing the Air Quality and Environmental Justice Benefits of Zero Emission Off-Road Vehicles and Equipment in California

Wed, 29 Oct 2025 00:00:00 +0000

Diesel fuel powered off-road vehicles and equipment used in agriculture, construction, mining, and industry have significant air quality and public health impacts due to high levels of pollutant emissions. Replacing these with zero emission powertrains represents a key strategy for reducing the harmful environmental impacts. However, the air quality impacts of zero emission off-road vehicles have not been assessed. Using the CMAQ model, we find that fully converting the off-road sector to zero emission equipment can decrease annual PM2.5 up to 0.9 μg/m3 and reduce daily maximum 8-hr average (MDA8) ozone as much as 6 ppb in Southern California. Statewide, these improvements yield benefits to public health potentially ranging up to $22.0 billion annually. The results further demonstrate the ability of zero emission off-road equipment to achieve health benefits within socially and economically disadvantaged communities.

Analyzing the 2012 California Household Travel Survey using R

Wed, 24 Sep 2025 00:00:00 +0000

The 2010-12 CHTS, which resulted from a statewide, collaborative effort, enabled the collection of travel information from 42,560 Californian households. This rich dataset has helped update regional and statewide travel and will help update environmental models.

In 2014, the Institute of Transportation Studies at Irvine (ITS) and Caltrans initiated the “Enhancing the Value of the 2010-12 California Household Travel Survey (CHTS)” contract. This contract was motivated by the idea that potential value of the CHTS is not always well understood by Caltrans staff and that some Caltrans staff from the Office of Travel Forecasting and Analysis may benefit from updating their knowledge of statistical modeling to comfortably query CHTS data and to estimate some common transportation econometrics models.

This report provides numerous examples of how to perform various types of statistical analysis on the CHTS. In chapter 2, we discuss the R language and environment for statistical...

Review Current Methods for Allocating Average Weekday Mobile Source Emissions to Weekend Days

Wed, 24 Sep 2025 00:00:00 +0000

This report provides a review of the California Air Resources Board’s current method for adjusting estimated emissions from on-road motor vehicles. These estimates are a critical feature of CARB’s air quality modeling efforts, which are an important tool for maintaining and improving California’s air quality.

The central approach of the method adjusts “average weekday” emissions estimates using fac- tors derived from measurements of diurnal and day-of-week variations in multi-class vehicle ac- tivity provided by Caltrans from automated vehicle classifer (AVC) data. The diurnal factors are used to adjust the inputs to the Direct Travel Improvment Model (DTIM), which provides gridded, hourly estimates that are assumed to represent general spatio-temporal emissions patterns on an average weekday. The day-of-week factors are used to adjust the average weekday county-wide emissions estimates produced by EMFAC, CARB’s tool for estimating emissions from on-road ve- hicles. The...

What Explains Trends in Orange County Transportation Authority Bus Ridership?

Wed, 3 Sep 2025 00:00:00 +0000

This report investigates whether the implementation in 2015 of California Assembly Bill 60 (AB 60) which requires the California Department of Motor Vehicles to issue a driver's license to applicants who can prove California residency even if they are not legal US residents was responsible for subsequent declines in Orange County Transportation Authority (OCTA) bus ridership. Changing socioeconomic conditions, poor connectivity, poor service quality, and increased competition from TNCs are possible reasons behind this negative trend. Another potential cause is the implementation in 2015 of AB 60. In this context, this study examines the association between changes in OCTA bus ridership and the inception of AB 60 while controlling for differences in transit supply, socioeconomic variables, gas prices, multi-family rent, and single-family home value. To explain changes in monthly average weekday ridership, we estimated four route-level fixed-effect panel regression models different...

Between the Forest and the Trees: Community Strategies to Transform Roadways in California’s San Joaquin Valley

Mon, 25 Aug 2025 00:00:00 +0000

Expanding participation of historically disenfranchised groups within decision-making processes is an important strategy to increase equity within transportation planning but traditional engagement practices (e.g., public meetings, focus groups) have historically done little to address the needs of disadvantaged communities. This study evaluates the opportunities and barriers to using a community steering committee participation model within transportation planning to advance equity and environmental justice. It utilizes interview and case study analysis to examine the experiences of residents and community leaders in prioritizing community-identified strategies to mitigate roadway hazards in three AB 617 communities in California’s San Joaquin Valley – Stockton, South Central Fresno, and Arvin/Lamont. It investigates the role resident and CBO members played in the prioritization, approval, and implementation of three strategies to transform roadways and mitigate air pollution,...

Job Access, Agency Cost, and VMT Impacts of Offering Microtransit alongside Fixed-route Transit

Fri, 18 Apr 2025 00:00:00 +0000

Public transit ridership has declined in major US cities over the past decade. Integrating traditional fixed-route transit with flexible microtransit has been proposed to enhance ridership, mobility, accessibility, and sustainability. This project surveyed California transit agencies on their microtransit services to identify challenges to integrating them with fixed-route services. An agent-based model combining the two modes of transit was developed to evaluate different operational designs. FleetPy, an open-source simulation tool, modeled microtransit dynamics. The study examined design impacts, such as fixed route headways and microtransit fleet size, in downtown San Diego and Lemon Grove, California. Results showed that while microtransit reduces fixed-route ridership and requires higher subsidies, it significantly boosts job accessibility.

Assessing the Charging-as-a-Service (CaaS) Model for EV Charging Deployment in California

Thu, 10 Apr 2025 00:00:00 +0000

Charging-as-a-Service (CaaS) is an innovative electric vehicle (EV) charging station model that allows customers access to EV chargers through a contract with a provider responsible for design, deployment, operations, and maintenance. Little is known about the motivations and experiences of stakeholders involved in CaaS operations, including providers, electric utilities, and customers. A grey literature review identified CaaS services, provider-described benefits, and utility-provided CaaS and charging services. Then, we conducted semi-structured interviews with 13 stakeholders to identify critical themes on interactions between stakeholders and the perceptions, challenges, and opportunities of the CaaS business model in addressing charging station needs in California. CaaS may have structural benefits to customer-owned chargers and could improve charger reliability, provide scalable solutions, and reduce customer fatigue with EV charging deployment. However, CaaS faces the same...

Modeling and Analyzing Cost Overruns, Delays, and Cancellations in Senate Bill 1 Projects

Thu, 12 Dec 2024 00:00:00 +0000

In 2017, California passed Senate Bill 1 (SB1) to bolster transportation infrastructure funding. Using data primarily from the California Department of Transportation (Caltrans)’s official SB1 progress reports, we analyze the severity of cost overruns, delays, and cancellations across SB1 Transportation Projects. Although events such as the COVID-19 pandemic likely caused some of these negative outcomes, our statistical models show consistent patterns of overruns associated with fiscal periods, programs, and geographic locations. Our results indicate that the common 20% contingency is generally insufficient, indicating the need for better risk estimation in project planning. We also suggest amplifying data transparency on project performance and re-evaluating project selection criteria to avoid rewarding underestimation of project costs and duration and penalizing accurate estimation.

Assessing the Potential for Densification and VMT Reduction in Areas Without Rail Transit Access

Mon, 21 Oct 2024 00:00:00 +0000

While transportation infrastructure and efficiency should inform where to build more housing, little is known about how housing allocation and development processes can be coordinated more systematically with transportation. To date, transportation-housing coordination has often relied on the densification of areas near rail transit stations, putting heavy burdens on these locations and their residents. Much less attention has been paid to how densification can be achieved in a more equitable manner by encompassing other sites. This report directs attention to non-rail locations, specifically low vehicle miles traveled (VMT) areas and bus corridors, and examines the challenges that can arise in promoting densification more broadly. It shows that data uncertainties can make it challenging to identify low VMT locations and that prioritizing only low VMT locations for residential development may have limited effectiveness in expanding housing opportunities in high opportunity areas....

Risk Assessment for Security Threats and Vulnerabilities of Autonomous Vehicles

Fri, 10 May 2024 00:00:00 +0000

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 our 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 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....

Transport Pricing Policies and Emerging Mobility Innovations

Wed, 21 Feb 2024 00:00:00 +0000

Transportation pricing policies aim to manage vehicular demand for parking, dense urban areas, roadways, and highway lanes. Although pricing policies take various forms, most were designed in a world before the sharing economy and ride-sourcing companies. Hence, the efficacy of existing pricing policies in a world with shared mobility services requires further consideration. Moreover, future pricing policies designed to handle private vehicles and shared ride-sourcing vehicles must consider the behavior of both sets of travelers and vehicle fleets. This study develops a conceptual framework to support systems level analysis of pricing policies for a world with private and shared vehicle usage. It qualitatively analyzes the impact of shared vehicles on the effectiveness of various pricing policies, while also considering the role of vehicle-to-infrastructure technology. This conceptual framework will support future research that uses activity-based travel demand and dynamic network...

Telecommuting and the Open Future

Sat, 6 Jan 2024 00:00:00 +0000

The COVID-19 pandemic has generated renewed interest in how telecommuting can alter the workings of our cities and regions, but there is little guidance on how to align planning practice with the new reality. This report synthesizes the research on telecommuting and its consequences to help planners better understand what effects may occur from the proliferation of telecommuting and what lessons can be drawn from research findings. Emphasis is on the broad relevance of telecommuting to many domains of planning, including housing, land use, community development, and inclusive place-making, while attention is paid to changes in travel demand, vehicle miles traveled (VMT), and greenhouse gas emissions. The research suggests that telecommuting can occur in a variety of ways, and its impacts are largely dependent not only on the type/schedule of telecommuting but on the built environment, transit accessibility, and other amenities/opportunities the location provides. The varying impacts...

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

Mon, 11 Dec 2023 00:00:00 +0000

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 CVs allows us to implement optimized traffic management strategies optimizing the efficiency of transportation infrastructure resources. In this study, we introduce a novel Integrated Corridor Management (ICM) methodology, which integrates underutilized Park-And-Ride (PAR) facilities into the global optimization strategy. To achieve this, we use 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, we develop a model that assesses potential delays experienced by vehicles in the corridor. Based on this model, we employ a novel centralized deep reinforcement learning (DRL)...

Reducing Degradation in High-Occupancy Lanes

Fri, 8 Dec 2023 00:00:00 +0000

Reducing Degradation in High-Occupancy Lanes

Reducing Congestion by Using Integrated Corridor Management Technology to Divert Vehicles to Park-and-Ride Facilities

Fri, 15 Sep 2023 00:00:00 +0000

Connected Vehicles (CV) technology offers significant potential for managing traffic congestion and improving mobility along transportation corridors. This report presents a novel approach using integrated corridor management (ICM) technology to divert CVs to underutilized park-and-ride facilities where drivers can park their vehicle and access public transportation. Using vehicle-to-infrastructure (V2I) communication protocols, the system collects data on downstream traffic and sends messages regarding available park-and-ride options to upstream traffic. A deep reinforcement learning (DRL) program controls the messaging, with the objective of maximizing traffic throughput and minimizing CO2 emissions and travel time. The ICM strategy is simulated on a realistic model of Interstate 5 using Veins simulation software. The results show marginal improvement in throughput, freeway travel time, and CO2 emissions, but increased travel delay for drivers choosing to divert to a park-and-ride...

Improved California Truck Traffic Census Reporting and Spatial Activity Measurement

Tue, 29 Aug 2023 00:00:00 +0000

The Federal Highway Administration (FHWA) vehicle classification scheme is designed to serve various transportation operational and planning needs. Many transportation agencies rely on Weigh-In-Motion and automatic vehicle classification sites to collect vehicle classification count data. However, these systems are not widely deployed due to high installation and operations costs. One cost-effective approach investigated by researchers has been the use of single inductive loop sensors as an alternative to obtain FHWA vehicle classification data. However, most models do not accurately classify under-represented classes, even though many of these minority classes pose disproportionally adverse impacts on pavement infrastructure and the environment. As a consequence, previous models have not been able to adequately classify under-represented classes, and the overall performance of the models are often masked by excellent classification accuracy of the majority classes, such as passenger...

New Methods for Monitoring Spatial Truck Travel Patterns in California Using Existing Detector Infrastructure

Wed, 5 Oct 2022 00:00:00 +0000

This study developed a methodology to accurately estimate network-wide truck flows by leveraging existing point detection infrastructure, namely inductive loop detectors. The tracking model identifies individual trucks at detector locations using advanced inductive signatures and matches vehicle pairs at detector locations, using an extended form of the Bayesian classification model to estimate matching and non-matching probabilities of the vehicle pairs Several vehicle feature selection and weighting methods including Self Organizing Map and K-means clustering were applied to better identify individual vehicles from signature data. It was shown that the proposed extensive feature processing enhanced vehicle identification performance even among vehicle pools sharing similar physical configurations. The developed model was tested along an approximately 5.5-mile freeway segment on I-5 and CA-78 in San Diego, California where only 67 percent of the total trucks were observed at...

Factors Affecting Development Decisions and Construction Delay of Housing in Transit-Accessible and Jobs-Rich Areas in California

Mon, 18 Jul 2022 00:00:00 +0000

Recent state legislation addresses California’s housing affordability crisis by encouraging new development in transitaccessible and/or jobs-rich areas. But policymakers lack key information about the effects of laws and plans on developers’ decisions about whether and where to build housing, and factors contributing to delays in receiving government development approvals in target areas. Drawing on a unique dataset detailing all residential projects of five units or more that were approved from 2014 through 2017 in selected California jurisdictions, this project analyzes how project attributes and transportation-related factors affected infill housing construction. We find that in cities with extensive transit infrastructure, new projects were generally located in parts of the city with high proximity to transit, but that proximity to rail stops or high frequency bus stops was not associated with extreme delays in project approval compared to all projects in general. The only...

California Hydrogen Infrastructure and ZEV Adoption Towards a Carbon Free Grid in 2045

Mon, 11 Jul 2022 00:00:00 +0000

The transportation sector is a major source of California’s greenhouse gas emissions, contributing 41% of the state total[1]. California policy is moving rapidly toward Zero Emission battery electric vehicles (BEV) and hydrogen fuel cell vehicles (FCV). Governor Newsom has issued an executive order that all new in-state sales of passenger vehicles should be Zero Emission Vehicles (ZEV) by 2035. Further, the California Air Resources Board has approved rulemaking requiring that more than half of trucks sold in the state must be zero-emissions by 2035, and all of them by 2045 [1a].California has the ambitious goal of achieving a 60% renewable electricity grid by 2030 and 100% carbon free grid by 2045. High penetration of variable renewable energy (VRE) requires seasonal storage to match supply and demand and hydrogen could be a possible candidate for this purpose [1b]. The author has developed the CALZEEV energy-economic model to study possible roles for hydrogen in a VRE intensive...

Life Cycle Assessment of Environmental and Economic Impacts of Deploying Alternative Urban Bus Powertrain Technologies in the South Coast Air Basin

Fri, 6 May 2022 00:00:00 +0000

To aid in addressing issues of air quality and greenhouse gas (GHG) emissions in the South Coast Air Basin, local transit agencies are considering a shift to battery electric buses (BEBs) and hydrogen fuel cell electric buses (FCEBs). Each of these options vary in their overall effectiveness in reducing different emission types over their life cycle, associated life cycle costs, ability to meet operational needs of transit agencies, and life cycle environmental footprint. This project carried out a life cycle-based analysis and comparison of the GHG emissions, criteria pollutant emissions, and other environmental externalities associated with BEBs and FCEBs, taking into account their ability to meet operational constraints of the Orange County Transportation Authority. From an environmental footprint perspective, this study found the following. First, both FCEBs and long-range BEBs have comparable impacts for global warming potential and particulate matter formation but when the...

Evaluation of the Air Quality and Greenhouse Gas Benefits of an Advanced Low‐NOx Compressed Natural Gas (CNG) Engine in Medium and Heavy‐Duty Vehicles in California

Thu, 28 Apr 2022 00:00:00 +0000

The goal of this research is to assess the greenhouse gas (GHG) emissions and air quality (AQ) impacts of transitions to advanced low‐NOx Compressed Natural Gas (CNG) engines in medium-duty vehicle (MDV) and heavy-duty vehicle (HDV) applications in California with a particular emphasis on renewable natural gas (RNG) as a fueling pathway. To evaluate regional AQ impacts in 2035, pollutant emissions from all end-use sectors are projected from current levels and spatially and temporally resolved. Scenarios are constructed beginning with both a conservative (Base Case) and more optimistic (SIP) case regarding advanced vehicle technology and fuels integration to provide spanning of potential impacts. To capture the impact of seasonal dynamics on pollutant formation and fate, two modeling periods are conducted including a winter and summer episode. To estimate the potential GHG impacts of transitions to advanced CNG engines in HDV and MDV, scenarios are evaluated under various assumptions...

Accessibility, Affordability, and the Allocation of Housing Targets to California’s Local Governments

Thu, 8 Apr 2021 00:00:00 +0000

California’s Housing Element law establishes processes for determining regional housing needs and allocating these housing needs to cities and counties in the form of numerical targets. This study assesses whether the state's housing allocation process achieves the state’s goals of promoting housing development in areas accessible to transit, jobs, and socioeconomic opportunities. Our first analysis compares the mechanism that the Southern California Association of Governments (SCAG) uses to allocate housing units to local governments with two simpler alternatives. For all three allocation mechanisms, we assess whether the resulting allocations align with the goal of promoting housing development in areas with high social mobility and near transit and jobs. We find that SCAG’s allocation method may be unnecessarily complex, and that simpler allocation methods – which are less susceptible to technical difficulties and political wrangling – could achieve the state’s policy objectives...

Resiliency Impacts of Plug-in Electric Vehicles in a Smart Grid

Mon, 8 Feb 2021 00:00:00 +0000

This project assesses the impact of plug-in electric vehicles (PEVs) on the resiliency of the electricity distribution system by: (1) Assessing the use of PEVs as a resiliency resource during grid outages (Mobility Services+), (2) Assessing and simulating the impact of PEVs on the distribution infrastructure during normal operations, and (3) Determining the local environmental impact of clustering PEVs. A previously developed model of a smart grid consisting of two distribution circuits and a distribution substation was modified to enable the use of PEVs in vehicle-to-home (V2H) and vehicle-to-grid (V2G) configurations. Scenarios were simulated in which PEVs were used to serve critical loads in a home or community shelters, and a model was developed to assess the feasibility of using PEVs in grid restoration, which determined the inrush current of the substation transformer to determine the required power and energy for startup. The use of clustered PEVs and scattered PEVs in...

The Causes and Consequences of Local Growth Control: A Transportation Perspective

Thu, 5 Nov 2020 00:00:00 +0000

In California, there has been a growing concern about housing unaffordability and its negative consequences, but it has remained unclear how transportation is related to this issue. This report synthesizes the literature on the causes and consequences of local growth control which has been viewed as one of the most significant barriers to expanding housing supply and thus managing travel demand more effectively. Emphasis is on what insights can be gained from the literature and what further research is needed to better understand how transportation influences and is influenced by growth control actions.

Transportation Plans: Their Informational Content and Use Patterns in Southern California

Thu, 10 Sep 2020 00:00:00 +0000

While a large amount of effort has been devoted to making and updating local transportation plans, little is known about the informational contents of these plans and their use patterns. This project attempted to identify key informational contents of Californian cities’ transportation plans and to investigate how the plan contents can be used by various stakeholders through (i) a plan content analysis of a sample of general plans (recently adopted by eight municipalities in Orange County, California) and (ii) a plan use survey and follow-up analysis of survey responses. All plans analyzed were found to convey a variety of information about their visions, goals, policies, and implementation strategies, but the plan content analysis revealed substantial variation in the way cities composed their general plans and integrated them with other plans/players. Compared to land use elements, circulation elements tended to focus more on their connections with other agencies (external consistency)...

Assessment of the Employment Accessibility Benefits of Shared Autonomous Mobility Services

Thu, 28 May 2020 00:00:00 +0000

The goal of this study is to assess and quantify the potential employment accessibility benefits of Shared Autonomous Mobility Service (SAMS) commute modes across a large diverse metropolitan region considering heterogeneity in the working population. To meet this goal, this study employs a welfare-based (i.e. logsum-based) measure of accessibility, obtained via estimating a hierarchical work destination-commute mode choice model. The employment accessibility logsum measure incorporates the spatial distribution of worker residences and employment opportunities, the attributes of the available commute modes, and the characteristics of individual workers. This research further captures heterogeneity of workers using latent class analysis (LCA). The LCA model inputs include the socio-demographic characteristics of workers to subsequently account for different worker clusters valuing different types of employment opportunities differently. The accessibility analysis results indicate:...

Evaluating the Impacts of Start-Up and Clearance Behaviors in a Signalized Network: A Network Fundamental Diagram Approach

Sun, 29 Dec 2019 00:00:00 +0000

Numerical simulations have shown that the network fundamental diagram (NFD) of a signalized network is significantly affected by the green ratio. An analytical approximation of the NFD has been derived from the link transmission model. However, the consistency between these approaches has not been established, and the impacts of other factors are still unrevealed. This research evalutes the impacts of start-up and clearance behaviors in a signalized network from a network fundamental diagram approach. Microscopic simulations based on Newell’s car-following model are used for testing the bounded acceleration (start-up) and aggressiveness (clearance) effects on the shape of the NFD in a signalized ring road. This new approach is shown to be consistent with theoretical results from the link transmission model, when the acceleration is unbounded and vehicles have the most aggressive clearance behaviors. This consistency validates both approaches; but the link transmission model cannot...

Policy and Literature Review on the Effect Millennials Have on Vehicle Miles Traveled, Greenhouse Gas Emissions, and the Built Environment

Mon, 25 Nov 2019 00:00:00 +0000

Vehicle travel has reduced substantially across all demographics in the 2000’s, but millennials or young adults born from 1985-2000 stand out as the group that has reduced vehicle travel the most. This reduction of travel among millennials is known as the millennial effect. This policy and literature review discusses insights from recent policy reports and literature regarding the millennial effect and identifies the prominent themes and gaps in our knowledge. The first section reviews existing research on the millennial effect on vehicle miles traveled (VMT). The second section discusses the influence of the built environment on the travel and activities of the millennial generation. The third section highlights scenarios describing the millennials effect’s potential magnitude and identifies topics for consideration in future scenario planning efforts. The final section discusses the uncertainty that exists regarding the future behavior of millennials and their influence on VMT...

An Analysis of Travel Characteristics of Carless Households in California

Fri, 1 Nov 2019 00:00:00 +0000

In spite of their substantial number in the U.S., our understanding of the travel behavior of households who do not own motor vehicles (labeled “carless” herein) is sketchy. The goal of this paper is to start filling this gap for California. We perform parametric and non-parametric tests to analyze trip data from the 2012 California Household Travel Survey (CHTS) after classifying carless households as voluntarily carless, involuntarily carless, or unclassifiable based on a CHTS question that inquires why a carless household does not own any motor vehicle. We find substantial differences between our different categories of carless households. Compared to their voluntarily carless peers, involuntarily carless households travel less frequently, their trips are longer and they take more time, partly because their environment is not as well adapted to their needs. They also walk/bike less, depend more on transit, and when they travel by motor vehicle, occupancy is typically higher....

The Effect of Trucks Dispatch Decisions on Pavement Damage and Other Externalities

Tue, 29 Oct 2019 00:00:00 +0000

External costs of freight trucks include air pollution, highway damage, and congestion. While diesel taxes reduce both the pollution and congestion externalities, we show that they worsen highway damage. We investigate the impact of fuel prices on cargo shipments using weight-in-motion data from New York and California. We obtained sensor readings on over 1.4 billion vehicle events. These data allow us to track daily changes in the weight and number of trucks at specific locations. We explain the average daily weight differential between New York and California as a function of the diesel price differential using unexpected weather as an instrument. We find that when fuel prices increase 10 percent, fuel use by heavy trucks declines 3.1 percent and average truck weight increases 3.2 percent. While total truck traffic decreases by around 1 percent, on net there is 19.6 percent more road damage. The dispatch effect changes the welfare comparison of using fuel taxes versus efficiency...

A Literature Review: Improving How Active Transportation Demand is Modeled and Evaluated

Tue, 29 Oct 2019 00:00:00 +0000

Local transportation agencies typically rely on traditional travel demand forecasting models that focus on highway and roadway improvements to optimize vehicular traffic. These models are not equipped to evaluate active transportation strategies which align with current State of California policies such as reducing vehicle miles traveled to cut greenhouse gas emissions and fostering active transportation modes. In this context, ITS at UC Irvine (ITS Irvine) was invited by Orange County Transportation Authority (OCTA) to propose, develop, and apply an approach to better model active transportation. This report represents the first phase of this work, which is a review of the recent literature on how to model demand for active transportation and an examination of OCTAM’s (OCTA’s own regional travel demand model) Active Transportation (AT) modeling tool to evaluate its potential for modification or incorporation into a new active transportation model. The following observations/suggestions...