research report

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

Publication Date

October 1, 2024

Author(s)

Michael Hyland, Jiangbo (Gabe) Yu, Younghun Bahk

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Transportation Economics, Funding, & Finance

Abstract

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, this report analyzes 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, the statistical models developed for this analysis show consistent patterns of overruns associated with fiscal periods, programs, and geographic locations. Results indicate that the common 20% contingency is generally insufficient, indicating the need for better risk estimation in project planning. Results 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.

research report

Is Micromobility Being Used in Place of Car Trips in Daily Travel (or “Trip Chains”)?

Publication Date

September 1, 2024

Author(s)

Hossain Mohiuddin, Dillon Fitch-Polse

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Travel Behavior, Land Use, & the Built Environment

Abstract

To understand the extent to which micromobility services such as bike-share and scooter-share are enabling car-lightlifestyles by replacing driving, this report explores the trip-chaining patterns of micromobility users. The research team used travel diary data collected from micromobility users in 48 cities across the US. Findings from their analysis shows that a considerable portion of car owners are leaving their cars at home when using micromobility. This suggests that, for a subset of users, micromobility can form part of a car-free or car-light day of travel, despite having a car available. In addition, micromobility services are supportive of complex trip chains that include both work and non-work trips with reduced reliance on cars. The use of micromobility services tends to entirely replace shorter car trips on shorter-length trip chains.

research report

EEZ Mobility: A Tool For Modeling Equitable Installation of Electric Vehicle Charging Stations

Publication Date

December 1, 2022

Author(s)

Ayse Tug Ozturk, Preston Hong, Marta Gonzalez, Scott Moura, Callie Clark

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

Public electric vehicle (EV) chargers are unevenly distributed in California with respect to income, race and education-levels. This creates inequitable access to electric mobility especially for low-income communities of color, which. are less likely to have access to home charging stations. These communities are also more likely to be located in areas with poor air quality and would therefore benefit from EV adoption. Currently programs exist in California that fund incentives for public EV chargers in “Disadvantaged Communities” but the process for identifying these communities does not consider key characteristics such as housing type, potential for local emission reduction, and the degree of access to private chargers that would maximize economic benefits to these areas and the state. This report and study develops a model-based tool that incorporates key additional information to predict economic benefits and health impacts to local communities to guide the location of public charging infrastructure. This tool will improve the equitable distribution of public funds by identifying three types of expected benefits: economic benefit to EV owners/users, economic benefit to infrastructure operators, and greenhouse gas and PM2.5 emission reductions.

published journal article

Brake and Tire Particles Measured from On-road Vehicles: Effects of Vehicle Mass and Braking Intensity

Publication Date

July 26, 2021

Author(s)

Yifang Zhu, Farzan Oroumiyeh

Areas of Expertise

Safety, Public Health, & Mobility Justice

Abstract

Vehicle exhaust emissions have been decreasing due to stricter regulations and advancements in control strategies. However, non-exhaust emissions from brake and tire wear have not been extensively regulated in the past, and their relative contribution to particulate matter (PM) in urban areas is increasing. This article examines the effect of a vehicle’s mass and braking intensity on brake and tire particles based on on-road data collected from three different types of vehicles under real-world driving conditions.

research report

Evaluating Universal Basic Mobility Pilot Programs in Oakland and Bakersfield, California

Publication Date

October 1, 2024

Author(s)

Angela Sanguinetti, Eli Alston-Stepnitz, Leslie Nelson, Emily Searl, Ashley DePew

Areas of Expertise

Safety, Public Health, & Mobility Justice

Abstract

Pilot programs in California and beyond are exploring universal basic mobility (UBM), which ensures everyone can access transportation services for basic needs. This report evaluated UBM-inspired pilot programs in Oakland and Bakersfield, via pre- and post-pilot surveys and interviews during the programs. Both pilot programs provided free-fare transportation services (shared micromobility in both cities and public transit services in Oakland) to populations vulnerable to transport poverty (residents of a low-income, minority-majority community in East Oakland and current and former foster youth in Bakersfield). Participants replaced car trips and/or walking with shared mobility and/or public transportation and reported improved access to jobs, food, health care, and social and recreational opportunities. The services helped participants carry out activities with more comfort and dignity and yielded social and cultural benefits. Lessons learned for program design and administration include the need for providing: some car-based services; clear communications throughout the program; training/support components for new mobility options; troubleshooting operations; and planning for turnover in program staff and fast changes in micromobility services.

policy brief

Universal Basic Mobility Pilot Programs in Oakland and Bakersfield Are Combatting Transportation Poverty

Publication Date

September 1, 2024

Areas of Expertise

Safety, Public Health, & Mobility Justice

Abstract

The concept of Universal Basic Mobility (UBM) calls upon policymakers to ensure all people have access to transportation services for basic needs like work, food, and healthcare. Pilot programs in California and beyond are testing UBM as a means to address the problem of transport poverty, often defined as a household spending more than 10% of their income on transportation (the average American household spends 16%). This policy brief highlights findings from a study by UC Davis researchers evaluating the economic, social, and environmental impacts of UBM-inspired pilot programs in two major California cities–Bakersfield and Oakland.

policy brief

Equity Assessment of Transportation Should Incorporate Materials,Supply Chains, and Targeted Mitigation Policies

Areas of Expertise

Safety, Public Health, & Mobility Justice

Abstract

This brief highlights results of a study to develop frameworks for assessing the life-cycle human health and climate change impacts from six types of transportation projects: (1) roadways; (2) marine ports; (3) logistical distribution centers; (4) railyards; (5) bridges and overpasses; and (6) airports. The research team conducted two case studies, one involving routine resurfacing and vehicle operations on roads within the San Francisco (SF) Bay Area using 2019 data; and the other involving annual marine, cargo, rail, and trucking operations at the Port of Oakland in 2020.

dissertation

Mobility Hubs: Lessons Learned from Early Adopters

Publication Date

June 1, 2022

Author(s)

Doug Arseneault