This study investigates the evolution of shared micromobility vehicle design and safety practices in the San Francisco Bay Area from 2017 to 2024. Shared micromobility includes e-bikes and e-scooters. Stakeholder interviews revealed that limited protected bike lanes, poorly designed or neglected e-bike and e-scooter fleets, deteriorating road infrastructure, and unsafe rider behavior have impeded the widespread adoption of shared micromobility in urban areas. There is a pressing need for consistent design standards for lighting, battery charging, braking systems, vehicle frames, and wheel sizing to further improve safety and vehicle durability. Recommendations include expanding protected bike lanes, improving road maintenance, offering e-bike riding lessons, promoting helmet use, and encouraging substance-free riding. Enhancing vehicle security and implementing battery safety protocols are also critical for improving charging accessibility and reducing theft and fire risks.

website

The Fight for Teralta Park: The History behind State Route 15 and California's First Freeway Cap

Publication Date

February 1, 2025

Associated Project(s)

Sharing the History and Present Legacy of Freeway Siting in California

Author(s)

Paul Ong, Chhandara Pech, Jacob Wasserman, Andres F Ramirez, Anastasia Loukaitou-Sideris, Leila Ullmann, Megan Riley

Areas of Expertise

Safety, Public Health, & Mobility Justice

View website

Abstract

This storymap examines the history behind California’s first freeway cap in City Heights, San Diego—a testament, despite its reduced scope, to the community activists who pushed for reparations after decades of harm.

Related Publications

website

Dividing Lines: How Route 99 Reshaped Fresno's Immigrant Communities and Communities of Color

website

Freeway Revolts and Racially Exclusive Participatory Planning: A History of Organized Opposition to Freeway Construction in Pacoima

website

From "Across the Tracks" to "Across the Freeway": A History of the Racialization and Exclusion behind the I-10 Freeway in Colton

policy brief

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

Publication Date

October 28, 2025

Associated Project(s)

Maximizing the Air Quality and Public Health Benefits of Zero-Emission Off-Road Equipment in Disadvantaged Communities

Author(s)

Michael MacKinnon, Kai Wu, Scott Samuelsen

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

View policy brief

Abstract

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. To address this issue, California has a range of policies and programs in place seeking a cleaner off-road sector beginning with Executive Order N-79-20, which sets a goal of 100 percent transition to zero emission (ZE) off-road vehicles and equipment by 2035 where feasible. Reflecting this, the California Air Resources Board (CARB) 2022 California Scoping Plan outlines ambitious ZE technology adoption, including hydrogen fuel cell and battery electric technologies. To better understand the implications of both current and future policies, this study quantifies 1) the benefits of off-road emission reductions from current policy and 2) potential additional benefits that can be achieved by increasing ZE adoption of off-road vehicles and equipment over and above the level considered feasible in the Scoping Plan up to and including a full transition to ZE.

Related Publications

research report

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

published journal article

State Preemption in Theory and Practice: The Case of Parking Requirements

Publication Date

October 17, 2025

Associated Project(s)

State Preemption and Parking Requirements

Author(s)

Amy Lee, Adam Millard-Ball, Michael Manville

View published journal article

Abstract

In U.S. law, states can override actions of local governments that contravene state interests. In practice, preemptions are often more ambiguous nudges, and local responses can vary by interpretation and interests. This paper explores one such case of state preemption: California’s 2022 law that limited local governments’ ability to require automobile parking. We find that the law’s complexity and ambiguity created intense debates about interpretations, in all jurisdictions, leading to heterogeneous implementation across cities. Local interests also motivated strategic responses to the law, which we present in a threefold taxonomy: cities interested in parking reform used it as a springboard; cities interested in parking reform but facing local resistance used it as a protective shield; recalcitrant cities treated it as an obstacle or subverted the law. Our analysis shows that preemption is not as clear cut as it seems, and what conditions help and hinder changes in actual outcomes.

published journal article

Development of a Pavement Design Catalog Through CalME and Life Cycle Cost Analysis

Publication Date

October 4, 2025

Associated Project(s)

City and County Pavement Improvement Center (Years 2-8)

Author(s)

Sampat Kedarisetty, John Harvey

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience

View published journal article

Abstract

Pavement design has advanced from traditional empirical methods to mechanistic-empirical (ME) approaches. The California Department of Transportation (Caltrans) and the University of California Pavement Research Center (UCPRC) have developed the California Department of Transportation (Caltrans) ME Structural Analysis Program for Flexible Pavements (CalME) ME design method. A comprehensive pavement design catalog is essential to facilitate broader implementation, especially by local governments. This study aims to create a detailed pavement design catalog using the CalME program, assisting local officials in their pavement design processes. The catalog considers variations in climate, traffic, and structural pavement types across different regions in California, providing a ready-to-use resource for local government officials. Moreover, a life cycle cost analysis (LCCA) was conducted to optimize the pavement designs included in the catalog. The LCCA ensures economic efficiency throughout the pavement’s design life by accounting for construction, maintenance, and rehabilitation costs. Three pavement treatment strategies were evaluated: preservation, rehabilitation, and a combination of preservation and rehabilitation treatments. The findings of this study indicate that governmental agencies can make informed, climate region and subgrade-specific pavement design decisions and develop cost-effective maintenance plans for the entire pavement service life. The LCCA results show that preservation treatments are the most cost-effective in high-traffic areas, whereas rehabilitation treatments offer the most significant economic benefits in low-traffic areas.

Related Publications

policy brief

Hot Mix Asphalt - Local government Model Specification

policy brief

Best Practices for Pavement: Pavement Condition Index

policy brief

Concrete pavement sample specifications

policy brief

Asphalt concrete compaction sample specifications

policy brief

Life Cycle Cost Analysis Comparison Spreadsheet

policy brief

Best Practices for Pavement When did you last review your concrete specifications? Writing concrete mix specifications to improve durability and sustainability

policy brief

Best Practices for Pavement: Is your asphalt only living half as long as it could? Writing and enforcing specifications for asphalt compaction

policy brief

What Can You Do With A County Road That You Can’t Afford to Maintain?

research report

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

Publication Date

October 29, 2025

Associated Project(s)

Maximizing the Air Quality and Public Health Benefits of Zero-Emission Off-Road Equipment in Disadvantaged Communities

Author(s)

Michael MacKinnon, Kai Wu, Scott Samuelsen

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

View research report

Abstract

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.

Related Publications

policy brief

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

research report

Advancing procedural equity in environmental benefit programs: Insights from California’s electric vehicle purchase programs

Publication Date

October 1, 2025

Associated Project(s)

Assessing Procedural Equity in California’s Electric Vehicle Purchase Programs

Author(s)

Rachel Connolly, Gregory Pierce, Viviana Morales

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

View research report

Abstract

The California Air Resources Board (CARB) offers several benefit programs that support residents with the transition to electric vehicles. The Clean Vehicle Assistance Program (CVAP) provided grants and financing to help low-income households purchase or lease electric vehicles from 2018–2024. The Access Clean California (ACC) program streamlines access to clean transportation incentives through a network of community outreach partners. This study examines procedural equity in these two programs through interviews with CARB staff, program administrators, community partners, and program participants. The study concludes CVAP fell short in several ways, including insufficient community engagement and a lack of targeted outreach, funding instability resulting in frequent program closures, and challenges in successfully distributing low-interest loans, while the ACC program has not fully simplified incentive access. The study recommends improved transparency in program reporting, regular third-party equity evaluations, strategic development of a truly equitable financing program, and refined funding allocation and administration to enhance equity outcomes.

Related Publications

policy brief

Bridging the procedural equity divide in California’s electric vehicle incentive programs

policy brief

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

Publication Date

October 22, 2025

Associated Project(s)

Exploring Opportunities to Improve Transit Access to Community Resilience Centers for Safety and Evacuation Planning

Author(s)

Elisa Borowski, Jeannine Pearce

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation

View policy brief

Abstract

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 sector decision makers must understand the function and impact of Resilience Hubs and ensure access to them. To better understand the role of social infrastructure like Resilience Hubs in supporting safety and hazard preparedness, as well as its integration with public transit, the researchers collaborated with one of Los Angeles’ first Resilience Hubs as of 2021: the Boyle Heights Arts Conservatory (BHAC). In partnership with the BHAC and the local non- profit Climate Resolve, the researchers collected data through three listening sessions with a total of 26 residents of Boyle Heights, Los Angeles, with connections to the BHAC. The research sought to amplify how residents of Boyle Heights experience cascading urban vulnerabilities and resilience, both in terms of physical and social infrastructure, as well as the improvements they envision for public transit integration with social infrastructure to enhance the resilience of both systems.

Related Publications

research report

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

policy brief

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

preprint journal article

Beyond Infrastructure: Patterns of Environmental Justice and Multi-Level Governance in Greater Los Angeles Transportation and Hazard Planning

policy brief

Bridging the procedural equity divide in California’s electric vehicle incentive programs

Publication Date

October 1, 2025

Associated Project(s)

Assessing Procedural Equity in California’s Electric Vehicle Purchase Programs

Author(s)

Rachel Connolly, Gregory Pierce, Viviana Morales

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

View policy brief

Abstract

As a leader in clean transportation initiatives, the California Air Resources Board (CARB) has long offered several benefit programs that support residents with the transition to electric vehicles, including the Clean Vehicle Assistance Program (CVAP) and Access Clean California (ACC). CVAP, which operated from 2018-2024, provided grants and loan financing to help low-income households purchase or lease electric vehicles. ACC, launched in 2018, uses an extensive statewide community outreach network of community-based organizations (CBOs) to connect eligible residents with a range of clean transportation and energy benefits. While there is substantial knowledge about the distributive equity outcomes of many of the state’s clean transportation programs, procedural equity—ensuring inclusivity in design, outreach, and other aspects of implementation—remains less explored. This study examined procedural equity in these two programs, selected for their innovative program designs and priorities beyond those of more long-standing, pure vehicle purchase credit or rebate approaches.

Related Publications

research report