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Sponsor: SB1

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

Status

Complete

Project Timeline

October 1, 2022 - December 31, 2023

Principal Investigator

Michael HylandMichael Hyland

Project Team

Jiangbo (Gabe) Yu, Arash Ghaffar

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2023-39
(Also see the UC ITS page)

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience

Team Departmental Affiliation

Civil and Environmental Engineering

Project Summary

Accurate estimates of infrastructure project costs, duration, and risks are critical in making informed decisions that can significantly impact quality of life in California. Caltrans’ preliminary examination of progress reports for projects that have been funded by the Road Repair and Accountability Act of 2017, commonly referred to as Senate Bill 1 (SB 1), reveals severe underestimates in project costs and timetables. Notably, these occurred even before the COVID pandemic. Few projects are expected to finish under budget or before the estimated completion date. This project examines the difference between initial SB 1 project cost and duration estimates in grant applications with the actual costs and completion times using publicly available data from SB 1 progress reports to identify the types of projects that are more likely to underestimate outcomes. Specifically, the research looked at which phases of a project are more prone to cost escalations and delays for different project types, infrastructure programs, and geographic locations. Results show consistent patterns of overruns associated with fiscal periods, programs, and geographic locations. In addition, results indicate that the common 20% contingency is generally insufficient, indicating the need for better risk estimation in project planning.

Related Publications

research report | Oct 2024

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

Read more
policy brief | Oct 2024

SB1 Project Performance: Cost Overruns, Schedule Delays, and Cancellations

Read more

Evaluating Heterogeneity in Transit Safety Perceptions and Reliability among Young Transit Riders

Status

In Progress

Project Timeline

October 1, 2024 - August 31, 2026

Principal Investigator

David Brownstone

Project Team

Henry Bernal, Chen (Cassie) Zhang

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2025-26
(Also see the UC ITS page)

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Safety, Public Health, & Mobility Justice

Team Departmental Affiliation

Economics

Project Summary

Safety and heightened exposure to crime on transit in recent years are increasing concerns that have received widespread media coverage. Young riders are particularly concerned about crime on transit at a time when fewer younger drivers are obtaining driver’s licenses. In Los Angeles, crimes covering LA Metro have risen 55 percent between 2020 and 2023 while violent crimes rose 11 percent between 2022 and 2023. This poses an equity issue to young riders, given a large majority of young riders on transit are from low-income households and need safe, fast, reliable service. This analysis will seek to determine how individual safety concerns and perceptions impact subjective values of travel time reliability. To do this, the researchers will survey Metro riders, many of whom also participate in GoPass, which has generated substantial cost savings for young Metro riders.

Analyzing the Effectiveness of Efforts to Reconnect Communities and Redress Past Harms in California

Status

In Progress

Project Timeline

January 13, 2025 - June 30, 2026

Principal Investigator

Doug Houston

Project Team

Shengxiang Jin

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2025-29

Areas of Expertise

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

Team Departmental Affiliation

Urban Planning and Public Policy

Project Summary

The federal government and California have adopted policies, developed programs, and allocated funds to redress the past and contemporary harms caused by transportation infrastructure development. They are committed to directing a significant portion of the benefits to disadvantaged communities. These efforts fall under the rubric of “reconnecting communities,” which aims to remedy past and ongoing injustice through new infrastructure. Equally important is the goal of meaningful stakeholder engagement, which requires rectifying biased participatory practices. This project aims to improve restorative justice (RJ) practices in transportation and infrastructure planning by evaluating the effectiveness of programs to redress harm caused by transportation infrastructures. The project team will use spatial analysis and a survey of several dozen Reconnecting Communities (RC) projects to identify those harmed and assess engagement practices used. The team will conduct six RC case studies throughout California to examine historical and contemporary infrastructure decision-making. Finally, the team will conduct a deep process study of advisory board decision-making processes in the Bay Area to understand types of government-led RJ engagement that can truly repair harms.

Improving Rail Emissions Estimation Using Vision-Based Monitoring and Operational Data

Status

In Progress

Project Timeline

September 1, 2025 - September 30, 2026

Principal Investigator

Stephen Ritchie

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2026-23

Areas of Expertise

Freight, Logistics, & Supply Chain Intelligent Transportation Systems, Emerging Technologies, & Big Data Safety, Public Health, & Mobility Justice

Team Departmental Affiliation

Civil and Environmental Engineering

Project Summary

Traditional rail emissions models oversimplify train operations, assuming fixed train composition and uniform railcar weight. Leveraging ITS-Irvine’s Rail Activity Monitoring System, this project develops a more accurate method to estimate emissions. It will also explore linking these estimates to real-world air quality measurements, supporting more precise policymaking and planning.

Examining the Safety and Efficiency Implications of Several Autonomous Car-following Models

Status

Complete

Project Timeline

August 1, 2021 - August 31, 2022

Principal Investigator

Wenlong Jin

Project Team

Ximeng Fan

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2022-39
(Also see the UC ITS page)

Areas of Expertise

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

Team Departmental Affiliation

Civil and Environmental Engineering

Project Summary

Autonomous vehicles hold promises for revolutionizing transportation, but they also face many challenges in both safety and efficiency. Traffic system managers need to know what kind of autonomous vehicles should be allowed to operate on California’s roads and what driving behavior to expect from them. Based on daily driving experiences, traffic rules, vehicle characteristics, and empirical observations, sound driving behavior should be collision-free, cars should be safely spaced and travel at reasonable speeds. Autonomous cars’ driving behaviors should satisfy these principles to be safe, efficient, and human-like. These principles have been used to develop car-following models and have been incorporated into standard Adaptive Cruise Control (ACC) systems, but these models tend to be too complicated to analyze, and there is no guarantee that they satisfy safe driving criteria. This research will systematically examine the safety and efficiency of different existing car-following models, ACC models, Artificial Intelligence-autonomous vehicle driving models, as well as the performance of Positioning, Navigation and Timing (PNT) and other sensing technologies. Using real world data, the researchers will calibrate the braking distances and the speed profiles of human-driven vehicles at signalized intersections. The project will then develop a new driving model to describe human drivers’ behaviors and prescribe autonomous vehicles’ driving policies. Further, the team will examine the impacts of PNT accuracy on the safety and efficiency of the model. This research may help to increase users’ confidence in the safety and performance of the transportation system.

Related Publications

policy brief | Jan 2025

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

Read more
Preprint Journal Article | May 2025

Provably safe and human-like car-following behaviors: Part 1. Analysis of phases and dynamics in standard models

Read more

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

Status

Complete

Project Timeline

September 25, 2023 - June 30, 2025

Principal Investigator

David Brownstone

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2024-32
(Also see the UC ITS page)

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation

Team Departmental Affiliation

Economics

Project Summary

While automobile traffic and freeway congestion have returned to pre-COVID levels, transit agencies continue to face declining ridership, staffing shortages, and service reductions. In the fall of 2021, LA Metro introduced the GoPass Fareless Initiative, offering free transit access to students in grades K-14 within eligible school and community college districts in Los Angeles County. The program's eligibility is determined by the community college district, which can opt in by paying a nominal cost-sharing fee of $3 per enrolled student per year. Students in districts that opt in can participate by acquiring a free pass and registering it with LA Metro. However, only about 15% of Los Angeles Unified School District students and 10% of Los Angeles Community College District students choose to participate in GoPass. The project has two main objectives: (1) to analyze the factors affecting enrollment, while controlling for socio-economic characteristics, and (2) to determine whether GoPass enrollment leads students to choose more sustainable modes of transportation. To achieve these goals, the researchers will survey students at the nine campuses in the Los Angeles Community College District. These campuses represent the majority of the community college population in Los Angeles County. The survey will gather information on employment, household composition, and non-academic travel activities. It will also ask participants about the availability of household vehicles, bicycles, and other transportation options to understand the factors that influence students' transportation choices. The researchers will then use the data to model GoPass participation and overall mode selection among the population of community college students.

An Overview of Free and Discounted Transit Fare Programs in California: What Did COVID Change?

Status

Complete

Project Timeline

January 1, 2024 - June 30, 2025

Principal Investigator

Jean-Daniel Saphores

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2024-50
(Also see the UC ITS page)

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation

Team Departmental Affiliation

Civil and Environmental Engineering

Project Summary

In this study, the research team will survey transit agencies in California to investigate the performances of their free and reduced transit fare pass programs, the impact of COVID-19 on these programs, and conduct an in-depth analysis of selected free and reduced transit fare pass programs. In 2019, the researchers explored the availability of these programs by conducting a survey of California transit agencies; the data were obtained from 59 transit agencies. This study will extend that 2019 work. This project will involve first surveying California transit agencies, starting with the 59 agencies who answered the 2019 survey. The team will investigate if their 2019 programs are still offered, if they were changed, and inquire if new programs were created (or are being considered). The researchers will inquire about the reasons for initiating each program, eligibility criteria, funding sources, ridership, and financial impacts. Finally, to promote public transportation through fare-based incentives, the investigators will create an online dashboard with information about all known free and reduced transit pass programs in California. This study will help evaluate the evolution of free and reduced transit fare programs during and after the COVID-19 pandemic.

Related Publications

policy brief | Dec 2025

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

Read more

Agent-based Modeling of the Impacts of Shared/Connected Mobility on Transit Systems and Potential Synergetic Options

Status

In Progress

Project Timeline

January 1, 2019 - December 31, 2019

Principal Investigator

r-jayakrishnanR. (Jay) Jayakrishnan

Project Team

Sunghi (Sunny) An, Dingtong Yang, Daisik (Danny) Nam, Eduardo Marino Fernandez

Sponsor, Program & Award Number

SB1 // STRP Faculty Research: 2019-34
(Also see the UC ITS page)

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data Public Transit, Shared Mobility, & Active Transportation

Team Departmental Affiliation

Civil and Environmental Engineering

Project Summary

Cities of the future demand a paradigm shift with the emerging and rapidly changing landscape of autonomous vehicles, shared mobility, connected vehicle technologies, and systems integration. System modeling is a necessary tool to study various policy alternatives due to the increasing complexity of future travel options. Unlike traditional top-down approaches for transportation planning, current and future transportation systems require more detailed representation of the various entities that interact with one another in ways that may or may not be collaborative, and whose collective behavior can lead to many possible outcomes both good and bad. This project will develop a comprehensive agent-based framework for system modeling (termed Autonomicity) for a collection of city contexts with the associated networks, demand-generation modules, supply-side details, business models, vehicles, goods and travelers that encompass the full spectrum of mobility in a future city. Associated research projects can use the Autonomicity framework / model to study specific topics, such as, the effects of ride-sharing systems or autonomous vehicles on the transit systems, or the system-wide effects of user-side subscription services from Transportation Network Companies (TNCs).

Analyzing the Impact of Land Use and Socio Demographics on Micro Transit

Status

Complete

Project Timeline

July 1, 2024 - September 30, 2024

Principal Investigator

Michael HylandMichael Hyland

Project Team

Tim Wang

Sponsor, Program

SB1 // PRIME

Team Departmental Affiliation

Civil and Environmental Engineering

Related Publications

presentation | Oct 2025

Analyzing the Impact of Land Use and Sociodemographics on Microtransit

Read more

CARB Activity- and Accessibility-Based Framework for Mobility Equity Evaluation

Status

Complete

Project Timeline

July 1, 2024 - September 30, 2024

Project Team

Daniel Lyons, Grayson Gallegos

Sponsor, Program

SB1 // PRIME

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