Recent itsirvine items

California Travel Post-Pandemic Has Changed: Are Our Policies Keeping Up?

Tue, 19 May 2026 00:00:00 +0000

The COVID-19 pandemic fundamentally changed how Californians travel, work, and shop. While overall travel levels have largely recovered, the rise of remote work, online shopping, and more flexible schedules have reshaped when, why, and how people travel. Yet many transportation policies and planning tools still rely on outdated assumptions about travel behavior, creating a growing mismatch between policy and reality, with implications for infrastructure planning, congestion, air pollutant emissions, and more. To better understand these changes, we analyzed travel data from 2019 and 2023 across four primary travel modes–driving, public transit, walking, and bicycling. To examine changes in driving and transit, we used data from sites around the state for driving and transit use, in additionto data from the Southern California Association of Governments (SCAG) region to analyze walking and biking.

California’s SB 375 Falls Short in Streamlining Transit-Oriented Development, But this Could be Fixed

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

In California and many other states, new development projects must undergo an environmental impact analysis as part of the approval process. In California, this happens through the California Environmental Quality Act (CEQA).

While CEQA is designed to ensure thoughtful consideration of environmental effects, it can also invite litigation that can delay or derail projects, even for projects that may benefit the environment, such as transit-oriented development (TOD). TOD aims to reduce vehicle miles traveled (VMT) and its associated impacts, such as greenhouse gas emissions (GHGs), by locating housing, jobs, and amenities near high-frequency public transit. But when environmental review requirements delay or discourage TOD, the result can be to push development to less accessible areas, leading to more driving, more emissions, and fewer housing options—

undermining the very goals CEQA was meant to protect.

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...

Making Workplace Charging Work: What Employees Value in Managed and Bidirectional Programs

Thu, 26 Mar 2026 00:00:00 +0000

California’s climate goals increasingly depend on shifting electric vehicle (EV) charging to midday, when clean, low-cost solar energy is most abundant. Doing so could help utilities avoid having to curtail solar energy and prevent reliability-driven infrastructure upgrades that would raise rates for all customers. Workplace charging programs are well positioned to support this shift, as many vehicles remain parked during daylight hours. However, workplace charging presents a cost dilemma. Since home charging is typically less expensive, employees may be reluctant to use workplace chargers unless prices are heavily discounted—yet offering free or low-cost charging extends the time it takes for employers to recoup infrastructure investments.

Planning Light-and Heavy-Duty ZEV Infrastructure for a More Resilient Fueling Network in California

Thu, 26 Mar 2026 00:00:00 +0000

Building a large, reliable, equitable network in a short time presents challenges of scale, reliability, and resiliency. One possible way to address these challenges is to combine light-and heavy-duty vehicle charging and fueling infrastructure, given the overlap of these vehicles’ travel patterns and of the respective charging and fueling technologies used. We investigated how this strategy could support robust charging and refueling networks for projected ZEV growth. To that end, we developed a “conservative” and an “optimistic” scenario to simulate charging and hydrogen fueling station deployment across California for 2025, 2035, and 2045.

Impacts of LA Metro’s K-14 Fareless Transit Initiative on Youth Travel Behavior

Mon, 9 Mar 2026 00:00:00 +0000

In October 2021, the Los Angeles Count Metropolitan Transportation Authority (LA Metro), in collaboration with other regional transit operators and multiple school districts across the county, launched the GoPass pilot program to offer free transit passes to K-14 students, which became permanent in early 2024. Students in a high school district in the Greater Los Angeles area were surveyed to determine the reasons students decided to participate in GoPass and how the students subjectively valued their travel preference. Students were less likely to participate in the GoPass program if they had the use of a car for trips to school but more likely if they had the option to take transit for trips leaving school. Student demographics did not play a large role in whether they participated in GoPass. Students highly value cars and trip amenities, such as onboard Wi-Fi. They subjectively value reduced travel time at $71/hour, similar to other studies among adults, but valued reduced...

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...

What Should Agencies Measure to Decide If Microtransit Is Working?

Fri, 30 Jan 2026 00:00:00 +0000

California state agencies, public transit agencies, and cities have invested in dozens of microtransit pilot programs, often with the stated goals of improving access, filling gaps in fixed-route public transit service, and serving communities that are difficult to reach by traditional bus or rail. As microtransit services mature, agencies increasingly face decisions about whether to expand, modify, or discontinue microtransit services—and how to allocate scarce operating funds across competing transit priorities.Despite growing investment, there is no consistent approach to measuring whether microtransit services are delivering meaningful benefits relative to their costs, or whether those benefits are equitably distributed. Without clear and well-balanced performance metrics, agencies risk drawing the wrong conclusions about success or failure.

Peak Pricing and Transfer Discounts Can Make Microtransit More Efficient

Wed, 7 Jan 2026 00:00:00 +0000

Microtransit offers flexible, on-demand rides that can fill gaps in public transit networks, especially for people who do not have access to a car and live in an area where fixed-route service is limited. However, operating these services is expensive. For example, LA Metro once reported a taxpayer subsidy of $43 per microtransit ride, and another California transit agency reported even higher costs. Additionally, because transit agencies offer low-cost, flat fares, demand for microtransit often exceeds service capacity during peak hours, leading to long wait times and unfulfilled trip requests.

Understanding How Caregivers Travel Can Help Strengthen Families and Inform More Equitable Transportation Policies

Fri, 19 Dec 2025 00:00:00 +0000

In communities like California’s Antelope Valley, caregivers (especially single parents, parents of children with disabilities, and those with limited financial or social support) face significant mobility barriers. Sparse and unreliable public transit, long travel times, and the high cost of driving make it difficult to access healthcare, work, and community resources. These barriers can worsen caregiver exhaustion, distress, and social isolation and contribute to missed healthcare and family support appointments.

Balancing Noise, Energy, and Time: Designing Advanced Air Mobility Operations for Urban Integration

Fri, 19 Dec 2025 00:00:00 +0000

As large cities face increasing urbanization and traffic congestion, Advanced Air Mobility (AAM) has emerged as a potential solution to inner and inter-city transportation challenges. Leveraging recent advancements in electrification, distributed rotors, and other aviation technologies, AAM aims to provide scheduled and on-demand passenger and cargo flights as a part of multimodal transportation networks. These flights are expected to operate at higher densities, lower altitudes, and in closer proximity to urban areas than legacy transport aircraft operations of the National Airspace System (NAS).

Free and Reduced Transit Fare Programs in California Increased After COVID-19–But Can it Last?

Thu, 11 Dec 2025 00:00:00 +0000

Free and reduced transit fare programs can boost transit ridership and benefit low-income individuals, students, seniors, and those with disabilities though financial sustainability is typically a concern. During the COVID-19 pandemic, transit agencies across California faced dramatic ridership declines and began expanding these programs—particularly for students—as a strategy to rebuild demand. Yet, little is known about how widespread free and reduced transit fare programs have become, what impacts they are having on ridership, and how agencies are funding them. To help address these questions, we surveyed California transit agencies in 2019 and 2024 and interviewed selected agencies to better understand how these programs are working in practice.

LA County’s GoPass Program Helped Build Transit Ridership While Enhancing Student Outcomes

Tue, 9 Dec 2025 00:00:00 +0000

In fall 2021, the Los Angeles County Metropolitan Transportation Authority (LA Metro) launched GoPass, which gives students from kindergarten through community college (K–14) at participating schools unlimited free rides on buses and trains. LA Metro designed the program to rebuild ridership, improve transportation access for disadvantaged communities, encourage life-long transit use, and lay the groundwork for seamless electronic payment for younger riders. By winter 2023, more than 241,000 students were enrolled, generating over 1.2 million monthly boardings–making GoPass the largest fareless program for students in the U.S.

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.

Switching to Zero Emission Off-Road Vehicles and Equipment Has Significant Air Quality and Environmental Justice Benefits in California

Tue, 28 Oct 2025 00:00:00 +0000

Off-road vehicles and equipment (e.g., forklifts, tractors, dirt bikes) are a major source of air pollution in California due to their heavy reliance on diesel engines, which emit high levels of nitrogen oxides (NOx), fine particulate matter (PM2.5), and other emissions. These pollutants cause a range of health impacts, including respiratory diseases like asthma, increased cancer risk, premature death, and other ailments, and disproportionately affect low-income communities located near highways, freight hubs, ports, and industrial areas.

Resilience Hubs are a Community Resilience Strategy That Should be Better Integrated Into Los Angeles’ Public Transit System

Wed, 22 Oct 2025 00:00:00 +0000

This research was motivated by the need to better understand how the hazard preparedness and resilience strategies of California’s public transportation system can be improved through integration with social and safety infrastructure. The study focuses on a specific type of social infrastructure called ‘Resilience Hubs’, which are community-operated and community-serving facilities that support residents in accessing resources and support during both everyday conditions and extreme events. Considering the potential of these hubs to enhance resilience and safety for historically marginalized individuals, public sectordecision makers must understand the function and impact of Resilience Hubs and ensure access to them.

Using a “Bathtub Model” to Analyze Travel Can Protect Privacy While Providing Valuable Insights

Tue, 14 Oct 2025 00:00:00 +0000

Transportation agencies increasingly rely on detailed trip data to analyze traffic patterns and plan infrastructure improvements. However, traditional data collection methods require extensive personal information about travelers’ origins, destinations, and routes, raising serious privacy concerns. Current “big data” approaches can track individual movements with alarming precision, often without explicit consent. As privacy regulations tighten and public concerns grow, transportation planners need alternative methods that balance analytical needs with privacy protection.To address this challenge, we evaluated the “bathtub model” as a privacy-preserving alternative to traditional traffic data collection methods. This simple, network-level approach treats all trips in a region as part of one system. Instead of tracking each person’s path, a bathtub model represents trips by how much distance they have left to travel. This lets us analyze network performance while protecting privacy.

The Missing Link in Automated Vehicle Safety: Projected Braking and Realistic Driving Behavior

Tue, 14 Oct 2025 00:00:00 +0000

As more automated vehicles (AVs) gradually appear on our roads, they must be able to safely interact with human drivers as well as existing infrastructure designed with human drivers in mind. Current car-following computer models—which determine how AVs adjust their speed and position relative to other vehicles—often struggle to replicate human drivingpatterns. This deficiency could lead to unpredictable AV behavior, potentially increasing crash risks, disrupting traffic flow, and creating problems at traffic lights and intersections designed for human drivers. If AVs brake much earlier or later than humans, drivers may be caught in ‘dilemma zones’ — unable to safely stop or proceed through the intersection. To address these challenges, we conducted a comprehensive analysis of existing car-following models and developed a novel multi-phase projection-based model that ensures safety while exhibiting human-like driving characteristics. This model is called ‘projection-based’ because...

Capacity Building is Key for Accelerating Open-loop Payments Adoption Among Transit Agencies

Tue, 30 Sep 2025 00:00:00 +0000

Open-loop payments systems allow riders to pay fares using general-purpose payment methods like credit cards, debit cards, or mobile wallets (Apple Pay, Google Pay), rather than being limited to a single transit agency’s own payment system. Broad adoption of open-loop payments offers major benefits for public transit, including lower costs, greater convenience for riders, and improved operational efficiency. The California Integrated Travel Project (Cal-ITP) has helped pave the way for transit agencies interested in this technology by providing resources, guidance, and hands-on support. Cal-ITP works directly with transit agencies to address known challenges and identify solutions to emerging barriers. Understanding how agencies decide whether to adopt open-loop and other technologies is key to ensuring the effectiveness of programs like Cal-ITP. To explore this, we surveyed transit agencies in California to identify the factors that influence adoption of open-loop payments.

Evaluating Equity in Transportation and Hazard Preparedness Plans: A Multi-Level Governance Approach

Mon, 29 Sep 2025 00:00:00 +0000

Environmental justice (EJ) principles are essential for addressing inequities in transportation and hazard preparedness; however, they are often applied in a fragmented manner. Historically, urban planning in the United States has created racial and economic divisions, particularly through policies like redlining and freeway construction that displaced communities of color. These practices have systematically and disproportionately exposed marginalized groups to environmental harms. The EJ movement has advocated for addressing these disparities through equity-focused policies. However, the integration of EJ principles into plans remains incomplete, with prior studies focusing on individual plans or jurisdictions, failing to consider broader governance systems and the need for equity to bridge multiple plan types.

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...

Leveraging Robotaxis to Support Transit Riders in Emergencies

Tue, 9 Sep 2025 00:00:00 +0000

Transportation systems are vulnerable to disruptive events. Rail transit systems are particularly vulnerable because their vehicles operate on fixed tracks, making it difficult for them to safely and efficiently bypass each other or disrupted sections of the rail network.To improve the resilience of transit systems in the future, we explored the use of shared automated vehicles (SAVs), also called robo-taxis, to pick up stranded passengers and deliver them to their homes or other drop-off locations, such as an unaffected transit stop. For example, transit agencies could have a contract with one or more SAV fleet operators that would allocate a certain number or percentage of their vehicles to provide transportation between stations in the transit network. The transit agency would pay a recurring fee (e.g., quarterly or annually) to ensure access to SAVs during a disruption. The transit agency will agree to pay the SAV fleet provider based on either (i) the number of travelers...

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,...

Opportunities and Challenges to Using Community Steering Committees to Advance Community-Identified Strategies and Transportation Equity

Tue, 19 Aug 2025 00:00:00 +0000

Disparities in exposure to roadway hazards (e.g., pollution, noise) remain stubbornly persistent due to structural inequalities embedded in the built environment. Research has consistently documented racial/ethnic and socioeconomic disparities in traffic exposures nationwide, including heightened exposure to heavy-duty truck traffic, a significant source of noise and pollution. Such disparities also exist in the provision of sidewalks, bike lanes, and street trees, which can help mitigate roadway dust, noise, and pollution and can increase pedestrian safety, encourage walking and cycling, and provide health benefits.

Charging-as-a-Service is anInnovative Business Model that Could Help with California’s Vehicle Electrification Goals

Fri, 25 Apr 2025 00:00:00 +0000

Access to electric vehicle (EV) charging infrastructure is critical to advancing California’s EV adoption goals. The California Energy Commission has projected the state needs “nearly 1.2 million” chargers by 2030 “to meet the fueling demands of 7.5 million passenger plug-in electric vehicles.” Currently, California has about 152,000 publicly available EV chargers. Innovative asset ownership models, like charging-as-a-service (CaaS), could help overcome some of the barriers to deploying and maintaining charging infrastructure. For example, CaaS providers could procure, install, maintain, and replace charging equipment for subscription customers. To better understand how CaaS solutions could expand EV use and charging access, we conducted semi-structured interviews with 13 CaaS companies, electric utilities, and customers to identify the perceptions, challenges, and opportunities of the CaaS business model in addressing charging station needs in California.

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...

New Insights from Satellite Data Show the Impact Trucks are Having on Communities in Southern California

Fri, 14 Mar 2025 00:00:00 +0000

The rapid growth in freight transportation, particularly heavy-duty trucks, poses significant environmental and public health challenges for communities near major ports and freeways. In areas such as those near the Port of Los Angeles and the I-710 corridor, communities are exposed to elevated levels of air pollution, noise pollution, and associated health risks. Traditional traffic data collection methods primarily concentrate on gathering traffic volume data for freeway segments or smaller areas, often overlooking heavy-duty vehicles across roadway networks and in local communities. To better understand the environmental impact and spatial distribution of heavy-duty truck traffic, we employed a deep learning approach to analyze satellite imagery and publicly accessible spatial data. This approach allowed us to identify and categorize heavy-duty trucks and shipping containers along critical freight routes and analyze impacts on adjacentcommunities.

A Review of Reduced and Free Transit Fare Programs in California

Wed, 5 Mar 2025 00:00:00 +0000

Free or reduced-fare transit passes have the potential to increase transit ridership, enhance the mobility of underserved groups (e.g., low-income, seniors, and youth), and reduce the environmental footprint of transportation. Under the right conditions, these programs can also help reduce traffic congestion and motor vehicle use. Transit agencies in different parts of the world have been experimenting with free or reduced-fare transit for decades, yet there are still substantial concerns about the impacts of free or reduced-fare transit on ridership as well as on the fiscal health of transit agencies. Some of these concernslinger partly because rigorous academic studies on free and reduced-fare transit passes are still rare.

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

Fri, 14 Feb 2025 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...

What are the Public Health and Environmental Implications of Drayage Truck Electrification Targets in California?

Wed, 5 Feb 2025 00:00:00 +0000

To better understand the implications of transitioning drayage trucks to zero-emission, we analyzed the health impacts and GHG freeway emissions from diesel-powered drayage trucks and the benefits of replacing them with zero-emission trucks, accounting for current and expected air quality regulations. Our study area stretched between the San Pedro Bay and the Inland Empire, home to large warehouse complexes. We focused on two years: 2012 (when pre-2007 drayage trucks were phased out in the Clean Air Action Plan), and 2035 (the deadline in Executive Order N-79-20). Our analyses incorporated projections of the size and composition of the vehicle fleets from data collected by the California Air Resources Board (CARB), estimates of future emission factors from the U.S. Environmental Protection Agency that account for projected technology improvements, and projected increases in cargo demand at the ports in 2035 compared to 2012.

Charging Infrastructure Decisions by Heavy-duty Vehicle Fleet Operators: An Exploratory Analysis

Sat, 25 Jan 2025 00:00:00 +0000

Insufficient charging/fueling infrastructure poses a major challenge to achieving U.S. policy goals for transitioning the heavy-duty vehicle (HDV) sector to zero-emission vehicles. Addressing the infrastructure needs of HDV fleet operators, who are key demand-side stakeholders, is crucial for developing effective solutions and strategies. This study investigates these needs through a fleet survey of California’s drayage sector, focusing on battery electric trucks. Key aspects examined include preferences for charging locations, access types, charging duration, time-of-day for charging, and innovative solutions like Truck-as-a-Service. Analyzing responses from 53 companies with varying fleet sizes, annual revenues, and operational characteristics, the study employed a comprehensive exploratory approach, utilizing descriptive analysis, thematic analysis, and hypothesis testing. Findings reveal that while most fleets preferred on-site...

A Choice Experiment Survey of Drayage Fleet Operator Preferences for Zero-Emission Trucks

Sat, 25 Jan 2025 00:00:00 +0000

Many U.S. states are supporting the transition of the heavy-duty vehicle (HDV) sector to zero-emission vehicles (ZEVs), with California leading the way through its policy and regulatory initiatives. Within various HDV fleet segments, California’s drayage fleets face stringent targets, requiring all vehicles newly registered in the Truck Regulation Upload, Compliance, and Reporting System to be ZEVs starting January 2024, and all drayage trucks in operation to be zero-emission by 2035. Understanding fleet operator behavior and perspectives is crucial for achieving these goals; however, it remains a critical knowledge gap. This study investigates the preferences and influencing factors for ZEVs among drayage fleet operators in California. We conducted a stated preference choice experiment survey, developed based on previous qualitative studies and literature reviews. With participation from 71 fleets of various sizes and alternative fuel...

What Matters Most to Drayage Companies When Considering a Zero-Emission Truck: Insights from Small and Large Fleet Operators

Wed, 22 Jan 2025 00:00:00 +0000

Drayage trucks (i.e., heavy-duty trucks that move containers and bulk freight between ports and rail facilities, distribution centers, and other nearby locations) are a critical part of port operations, however, they also adversely affect air quality. In California, drayage fleets are facing strict regulatory pressure under the Advanced Clean Fleets (ACF) regulations. Starting in January 2024, all newly registered drayage trucks in the CARB Online System must be zeroemission vehicles (ZEVs), so either a battery electric truck (BET) or hydrogen fuel cell electric truck (HFCET). By 2035, every drayage truck operating in California must be zeroemission.

Robo-Taxis Are Likely to Increase Job Accessibility, Especially Among Low-Income Households

Wed, 15 Jan 2025 00:00:00 +0000

After years of research and development, companies are now operating fully driverless shared-use automated vehicle-enabled mobility services (SAMS) or “robo-taxis“ in Arizona and California. SAMS offer several potential benefits to travelers and society including reducing vehicle ownership, parking demand, congestion, crashes, energy consumption, and emissions, as well as increasing roadway capacity, mobility, and accessibility. Moreover, previous research by our team found that SAMS can provide significant job accessibility benefits to workers in California. To better understand the equity implications of the job accessibility benefits from SAMS, we analyzed the distribution of SAMS benefits across different segments of the population (e.g., low- vs. high-income, young vs. old).

Navigating the Shift: Critical Insights of California Fleet Operators into Zero-Emission Technologies

Wed, 15 Jan 2025 00:00:00 +0000

California is committed to transitioning heavy-duty vehicles (HDVs) from diesel to zero-emission vehicles (ZEVs) like battery electric vehicles (BEVs) or hydrogen fuel cell electric vehicles (HFCEVs) by 2045, and in certain cases much sooner. Achieving this goal requires substantial efforts from various sectors, including vehicle manufacturers, infrastructure developers, and governments. It is particularly important to understand the perspectives of HDV fleet operators, as their viewpoints and willingness to adopt ZEVs will be critical to California’s success in this transition. To better understand the perspective of fleet operators, we conducted in-depth interviews with 18 California HDV fleet operators, across various sectors and fleet sizes, on the viability of zero-emission fuels and vehicles over the next 10 to 20 years and the main motivators for, and barriers to, procuring ZEVs.

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.

A Review of SB 1 Project Performance: Cost Overruns, Schedule Delays, and Cancellations

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

The Road Repair and Accountability Act of 2017 (Senate Bill 1 or SB 1) aims to improve and enhance California’s transportation infrastructure. Like many infrastructure programs, however, there are concerns with project cost overruns, delays, and cancellations, as these can undermine program goals and negatively impact quality of life in California. To better understand SB 1 program performance thus far, we analyzed quarterly Caltrans SB 1 project reports between 2018 and 2023 to provide insights into project costs, delays, and cancellations.

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....

What Challenges Can Arise from Coordinating Housing Development with Transportation?

Tue, 1 Oct 2024 00:00:00 +0000

More systematic coordination between transportation and housing development is increasingly recognized as a promising strategy for creating more sustainable communities. In California, the importance of transportation-housing coordination is reflected in recent legislative efforts to address the state’s long-standing housing affordability crisis. One approach is to encourage higher density affordable housing developments near transit or in similarly transportation-efficient areas, such as locations with low vehicle miles traveled (VMT). However, little is known about how transportation access should be considered in guiding housing development, what challenges can arise from coordinating housing development with transportation, and what the state can do to better deal with these challenges and achieve more equitable residential densification.

Decline of Rail Transit Requires New Strategies

Fri, 13 Sep 2024 00:00:00 +0000

During the pandemic, California’s four major rail systems— Bay Area Rapid Transit (BART), San Diego Metropolitan Transit System (MTS), Sacramento Regional Transit (SacRT), and Los Angeles County Metropolitan Transportation Authority (LA Metro)—experienced an average ridership decline of 72 percent between 2019 and 2021. BART had the greatest decrease (87 percent) and MTS the lowest (47 percent). However, ridership changes varied significantly across individual stations, with stations located in the central business district or at the end of lines having the highest ridership losses. Land use, development density, and the pedestrian environment are strongly associated with station-level transit ridership. We examined how these characteristics affect transit ridership pre- and post-COVID and how they differ across station types based on longitudinal data collected between 2019 and 2021 for 242 rail stations belonging to BART, MTS, SacRT, and LA Metro.

Did Extending Driver Licenses to Individuals Without Legal Presence Affect Transit Ridership in Orange County?

Wed, 11 Sep 2024 00:00:00 +0000

In this study, we examine if observed line-level changes in OCTA bus boardings could be partly attributed to AB 60, while controlling for differences in transit supply, socioeconomic variables, gas prices, and the built environment. Using fixed effects panel data models, we analyzed monthly boardings on different OCTA route classifications—local, community, Express, and station link routes—one year before (2014) and two years after (2015 and 2016) AB 60’s implementation.

A New Approach to Calculating Dynamic Pricing of High-Occupancy-Toll (HOT) Lanes Can Improve the Performance of Travel Corridors

Wed, 11 Sep 2024 00:00:00 +0000

There are two operational objectives for optimizing the operation of HOT lanes: (i) maintain free-flow conditions on HOT lanes and (ii) move as many vehicles as possible through HOT lanes to minimize the travel corridor’s total delay. Meeting these objectives will help guarantee trip time reliability of both HOVs and paying SOVs and minimize congestion on general purpose (GP) lanes. The key factor in achieving these objectives is the price charged to SOVs, which determines the percentage of SOVs choosing to use the HOT lanes. This in turn requires operators to adjust the toll fee in response to changing levels of traffic congestion. However, achieving these goals efficiently is contingent upon dynamic pricing strategies where tolls are adjusted in real time in response to traffic levels to maximize the total throughput while preventing queuing on the HOT lanes.

An L.A. Story: Higher Housing Costs Lengthen Commuting

Fri, 6 Sep 2024 00:00:00 +0000

Concerns about the environmental impacts of transportation have made reducing vehicle miles traveled (VMT) a policy priority. One way to decrease VMT is to decrease the length of commuting trips, and to get commuters out of their private vehicles. Unfortunately, the average one-way commute keeps getting longer in the U.S., increasing from 25.1 to 27.6 minutes between 2005 and 2019. The percentage of work trips made by private vehicle has also soared, jumping from 66.9 percent in 1960 to 84.8 percent in 2019. As commuting typically occurs during traffic peaks, it is a major contributor to congestion and air pollution.

Grocery Shopping in California and Covid-19: Transportation, Environmental Justice, and Policy Implications

Fri, 6 Sep 2024 00:00:00 +0000

The COVID-19 pandemic upended many aspects of our lives, including how we shop for groceries. As grocery stores scaled back their opening hours and managed access, many shoppers switched to online shopping with home delivery (“e-grocery”) or store pick-up (“click-and-pick”). Few empirical studies published to date have explored how the COVID-19 pandemic changed grocery shopping, the extent to which these changes may last, how the pandemic exacerbated grocery store access inequalities, and how access to groceries in California is intertwined with environmental justice concerns. Moreover, most studies on this topic were based on non-random samples, which can provide quick results in a fast-changing environment but their findings are not generalizable.

Transitioning to Electric Drayage Trucks May Help Avoid Adding New Freeway Lanes to Freight Corridors in Southern California

Wed, 28 Aug 2024 00:00:00 +0000

Much has been written about the potential benefits of electric and connected vehicles. However, one important, but often overlooked, implication of electrifying trucks is that if they are powerful enough (such as the Tesla semi), they can eliminate the moving bottleneck or queuing effect created by slow-moving conventional heavy-duty trucks because electric trucks are much more responsive compared to conventional diesel trucks because electric motors provide maximum torque from a standstill. This could substantially increase road capacity in areas with high commercial truck traffic, especially around major ports or logistics complexes, thus alleviating the need to add new lanes to local freeways.

Integrating Microtransit Service with Traditional Fixed-Route Transit Costs More but Greatly Improves Access to Jobs

Wed, 28 Aug 2024 00:00:00 +0000

Microtransit is a mobility service that dynamically routes and schedules 6- to 20-seat vehicles to serve passengers within a defined region. Microtransit services are similar to ride-pooling services operated by Transportation Network Companies (e.g., Uber, Lyft); however, microtransit services are owned by cities or transit agencies. Integrating microtransit services with traditional fixed-route transit (FRT) has been touted as a means to attract more riders to public transit generally, improve mobility and sustainable transportation outcomes (e.g., reduce greenhouse gasses and local pollutants), and provide better accessibility to disadvantaged travelers. However, few academic studies have evaluated these claims. To address this gap, we surveyed California transit agencies that currently operate or recently operated microtransit services to obtain insights into integration challenges. We also developed an agent- and simulation-based modeling framework to evaluate alternative...

Did COVID-19 Fundamentally Reshape Telecommuting in California?

Tue, 13 Aug 2024 00:00:00 +0000

Health concerns and government restrictions during the COVID-19 pandemic caused a sharp increase in telecommuting (i.e., doing paid work at home or possibly an alternate worksite). In addition to reducing vehicle miles traveled (VMT), decreasing energy use, and lowering emissions of air pollutants and greenhouse gases (GHG), telecommuting may offer numerous other co-benefits, including increasing the worker pool, decreasing time and costs associated with travel, improving work-life balance, and decreasing stress. It may also stimulate greater use of non-motorized and active modes of travel (e.g., walking, biking, taking transit).

Shifting Future Electric Vehicle Trips to e-Bikes Could Help Reduce Electricity Demand at Critical Times in California

Tue, 13 Aug 2024 00:00:00 +0000

California aims to replace gasoline and diesel light-duty vehicles (LDVs) with zero-emission LDVs, many of which will be plug-in battery electric vehicles (BEVs) and achieve 100% zero-carbon electricity by 2045. Large-scale plug-in BEV deployment will substantially increase electricity demand, particularly during peak hours (4:00pm to 9:00pm) when renewable energy is in short supply. Popular strategies for charging BEVs with electricity produced from renewable energy include smart charging and creating more energy storage that soaks up renewable energy during the day and dispenses it later when needed. These strategies, however, may not be enough. Consumer acceptance limits smart charging, and increased energy storage capacity is expensive. Another potential strategy involves lowering the overall demand for electricity by shifting BEV trips to electric-powered bicycles (e-bikes). While e-bikes cannot entirely replace BEV trips, they are ideal for short trips (five miles or less)....

Automated Vehicles and Transportation Network Companies Will Likely Impact the Efficacy of Transportation Pricing Strategies

Tue, 6 Aug 2024 00:00:00 +0000

Transportation pricing strategies aim to manage vehicle travel demand, collect revenue, or force drivers to internalize the costs they impose on other persons (e.g., delayed travel time) and physical infrastructure. Pricing strategies include parking pricing, cordon- and area-based congestion pricing, road-usage charges (RUCs), and high-occupancy toll (HOT) lane pricing. These pricing strategies were, however, designed before the advent of ride-sourcing companies (i.e., Transportation Network Companies or TNCs) and automated vehicles (AVs). Hence, the efficacy of existing pricing strategies in a world with TNCs and a future world with AVs is unclear. Moreover, future pricing strategies must consider the behavior of TNC fleet operators in addition to private vehicle drivers.

A Comparison of Time-use for Telecommuters, Potential Telecommuters, and Commuters during the COVID-19 Pandemic

Wed, 10 Jul 2024 00:00:00 +0000

Throughout the ongoing COVID-19 pandemic, changes in daily activity-travel routines and time-use behavior, including the widespread adoption of telecommuting, have been manifold. This study considers how telecommuters have responded to the changes in activity-travel scheduling and time allocation. In particular, we consider how workers utilized time during the pandemic by comparing workers who telecommuted with workers who continued to commute. Commuters were segmented into those who worked in telecommutable jobs (potential telecommuters) and those who did not (commuters). Our empirical analysis suggested that telecommuters exhibited distinct activity participation and time use patterns from the commuter groups. It also supported the basic hypothesis that telecommuters were more engaged with in-home versus out-of-home activity compared to potential telecommuters and commuters. In terms of activity time-use, telecommuters spent less time on work activity but more time on caring...

Perceptions of Neighborhood Change in a Latinx Transit Corridor

Tue, 9 Jul 2024 00:00:00 +0000

Understanding how residents feel about neighborhood changes due to new development along transit corridors (often referred to as transit-oriented development) remains understudied despite growing concerns over displacement and gentrification. Studies that examined these concerns are largely based on analyzing land use, housing values, and socio-economic shifts (i.e., who is moving in and out of neighborhoods), and do not provide conclusive evidence that transit-oriented development (TOD) is linked to neighborhood gentrification and displacement. Prior surveys of residents living near transit indicate a generally positive assessment of TOD in terms of improved walkability and accessibility but also express concerns over pedestrian safety and parking related to increased traffic and new commercial development. However, recent studies counter this relatively positive assessment of TOD, particularly among activists and community organizers in low-income communities of color.

How Risky Are Cyber Security Threats Against Autonomous Vehicles?

Mon, 3 Jun 2024 00:00:00 +0000

To operate safely, autonomous vehicles (AVs) rely on external sensors such as cameras, light detection and ranging (LiDAR) technology, and radar. These sensors pair with machine learning-based perception modules that interpret the surrounding environment and enable the AV to act accordingly. Perception modules are the “eyes and ears” of the vehicle and are vulnerable to cybersecurity attacks. The most critical and practical threats, however, arise from physical attacks that do not require access to the AV’s internal systems. The risks of these types of attacks are still unknown. To advance the field in this area, we conducted the first ever quantitative risk assessment for physical adversarial attacks on AVs. First, we identified relevant attack vectors, or types of cyber security attacks, targeting AV perception modules. Next, we conducted an in-depth analysis of the stages of an attack. Finally, we used these exercises to identify risk metrics and perform a subsequent computation...

Travel Varies Greatly Between Voluntary Versus Involuntary Carless Households in California

Wed, 29 May 2024 00:00:00 +0000

In spite of the critical importance of mobility for quality of life and economic well-being, the travel behavior of households without motor vehicles has received insufficient attention even though “carlessness” may bethe most vivid expression of mobility disadvantage in our car-centric society. Approximately 10.6 million (9 %) of U.S. households do not own a motor vehicle (car, pickup, van, SUV, or motorbike), including over one million in California. These “carless” households form two groups: (1) involuntarily carless households who are forced to live without cars, and (2) voluntarily carless households who chose to do so. Since one of the strategic goals of federal transportation policy is “to increase transportation choices and access to transportation services for all” it is essential to understand the travel behavior of households who are unable to own a motor vehicle. Indeed, many involuntarily carless households are experiencing economic hardship, disabilities, racial...

COVID-19 Vaccination Rates Influenced Bus Ridership Recovery

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

COVID-19 has had lasting effects on transit ridership, with the worst declines seen in high-income, better educated, urban neighborhoods. However, declines among immigrant and/or low-income households was well documented prior to the pandemic, as more gained access to private vehicles. This has created a unique challenge for transit agencies to bring riders back to transit in cases where they may have already switched to traveling by car or consciously chose to make fewer trips. To better understand ridership during the pandemic, we documented the recovery of bus ridership in Los Angeles County and its relationship with COVID-19 vaccinations between April and December 2021, before the Omicron COVID-19 wave. We then developed a statistical model that relates LA Metro bus ridership as a percentage of October 2019 levels with the percent of adults fully vaccinated by ZIP code. We tested whether the relationship between vaccinations and bus ridership varied by two events: first, the...

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....

Higher Bus Ridership Unlikely to Increase Community COVID-19 Transmission

Wed, 24 Apr 2024 00:00:00 +0000

Public transportation has been blamed for facilitating the spread of COVID-19 in dense, urban areas. As a response to the COVID-19 pandemic, transit agencies have reduced service and implemented mask-wearing mandates and social distancing aboard transit. Some prior studies that address public transportation provide some evidence that negative COVID-19 outcomes are linked to high transit use. One early study of COVID-19 transmission on trains in China found that transmission is also affected by the density of passengers, seat spacing, and length of time traveled with other passengers aboard the trains.

A Review of Reduced and Free Transit Fare Programs in California

Fri, 22 Mar 2024 00:00:00 +0000

Free or reduced-fare transit passes have the potential to increase transit ridership, enhance the mobility of underserved groups (e.g., low-income, seniors, and youth), and reduce the environmental footprint of transportation. Under the right conditions, these programs can also help reduce traffic congestion and motor vehicle use. Transit agencies in different parts of the world have been experimenting with free or reduced-fare transit for decades, yet there are still substantial concerns about the impacts of free or reduced-fare transit on ridership as well as on the fiscal health of transit agencies. Some of these concerns linger partly because rigorous academic studies on free and reduced-fare transit passes are still rare.

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...

What Does the Prevalence of Telecommuting Mean for Urban Planning?

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

Researchers at the University of California, Irvine, are looking into what may become the “new normal” in work and work-related travel and the consequences that could have on traffic conditions, efforts to address climate change, and the future of our urban areas, as well as our daily lives. They find, for instance, that current research is largely equivocal about the consequences of telecommuting on where individuals choose to live, their day-to-day travel, and urban/metropolitan development. Equally unclear is how increased telecommuting may impact efforts to create more sustainable and inclusive communities. In light of this uncertainty, they suggest planners and researchers need to pay more attention to the changing nature of urban commuting and how it can play an important role in shaping a more desirable future.

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...

Connected Vehicle Technology and AI Could Help Reduce Highway Congestion through Better Utilization of Park and Ride Facilities

Thu, 7 Sep 2023 00:00:00 +0000

Considerable advancements have been made in traffic management strategies to address highway congestion over the past decades; however, the continuous growth of metropolitan regions has impeded such progress. In response, transportation planners have given special attention to integrated corridor management (ICM), an approach that coordinates various traffic control units (e.g., ramp metering) to optimize their operations along the entire freeway. Emerging connected vehicle (CV) technology is expected to substantially benefit ICM, where vehicles can communicate with each other and surrounding roadway infrastructure. The combined potential of ICM strategies and CVs could be even greater if combined with strategies that leverage underutilized infrastructure (specifically park-and-ride facilities) to reduce the total number of vehicles on the roadway.

What Drives Shared Micromobility Ridership?

Wed, 30 Aug 2023 00:00:00 +0000

Shared micromobility (e.g., e-scooters, bikes, e-bikes) offers moderate-speed, space-efficient, and “carbon-light” mobility, promoting environmental sustainability and healthy travel. While the popularity and use of shared micromobility has grown significantly over the past decade, it represents a small share of total trips in urban areas. To better understand shared micromobility ridership, researchers from across the U.S. and the world have analyzed statistical associations between shared micromobility usage and various explanatory factors, including socio-demographic and -economic attributes, land use and built environment characteristics, surrounding transportation options (e.g., public transit stations), geography (e.g., elevation), and micromobility system characteristics (e.g., station capacity). To understand what these studies collectively mean in terms of expanding shared micromobility usage, we conducted a meta-analysis of 30 empirical studies and then developed robust...

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...

Transportation Access, Urban Problems, and Intrametropolitan Population and Employment Changes