Our Experts

Scott Hardman

Professional Researcher, Electric Vehicle Research Center, UC Davis

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data Travel Behavior, Land Use, & the Built Environment Zero-Emission Vehicles & Low-Carbon Fuels

Recent Projects

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Research Team:

Scott Hardman (lead)

UC Campus(es):

UC Davis

Research Team:

Scott Hardman (lead), Maha Shafeen

UC Campus(es):

UC Davis

Brace for Impact: The Environmental and Economic Effects of Shifting Passenger Travel from Airplanes to High-Speed Rail

Status

Complete

Project Timeline

July 20, 2020 - June 30, 2021

Principal Investigator

J.R. DeShazo

Project Team

Jason Karpman, James Di Fillippo

Areas of Expertise

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

Campus(es)

UCLA

Project Summary

Aviation is the most greenhouse gas (GHG) intensive mode of transport for intrastate trips. Yet, there is no clear pathway for decarbonizing this sector. In the meantime, reducing GHGs from aviation requires shifting trips from the air to the ground, either by train or motor vehicle. There is a growing body of research that has documented the GHG implications of this diversion, but there are relatively few studies that have focused on other environmental and economic tradeoffs, or the efficacy of various policy instruments at facilitating this diversion. Researchers at the UCLA Luskin Center for Innovation propose synthesizing the peer reviewed and grey literature on: (1) the societal tradeoffs of shifting passenger and cargo transportation from the air to the ground; (2) the policy instruments for facilitating this shift; and (3) the interaction of these instruments with the various motivations behind mode choice. The synthesis will pull out key takeaways for policymakers and transportation planners in California, where the construction of an interregional high-speed rail network is already underway. The findings from this synthesis could help inform the state’s efforts to stimulate an economic recovery in the wake of the COVID-19 pandemic, while also leading the way towards carbon neutrality.

policy brief

On-Road Motor Vehicles No Longer Dominate Ozone Formation

Areas of Expertise

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

Abstract

The amount of traffic on California’s roadways decreased by approximately fifty percent during the COVID-19 pandemic lockdown in March and April of 2020. Conventional wisdom led to the expectation that reduced traffic would result in reduced ozone (O3) concentrations—ozone being a main component of smog—yet ozone concentrations increased during this period. Internal combustion vehicles emit oxides of nitrogen (NOx) and volatile organic compounds (VOCs). These emissions are precursors for ozone formation, but the relationship between these precursor emissions and the final ozone concentration is complex. The ratio of NOx/VOCs determines if the ozone formation will be “NOx-limited” or “NOx-rich”. Major NOx reductions are required to reduce ozone concentrations when the atmosphere is NOx-rich. Small NOx reductions in a NOx-rich atmosphere can actually increase ozone concentrations.

To inform ongoing efforts to reduce ambient O3 concentrations, this brief highlights findings from research that collected and analyzed air pollution measurements in urban locations adjacent to major freeways in the City of Sacramento and the City of Redlands—both during and after COVID-19 stay-at-home orders. The results provide an updated estimate for how many more years of NOx control will be required before O3 benefits are realized.

published journal article

Does Discretion Delay Development?

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Problem, research strategy, and findings:
Local governments sometimes approve multifamily housing through a discretionary process, meaning a public body must vote to entitle the proposal before it can seek a building permit. By-right entitlement, in contrast, allows developers to apply directly for a building permit. We tested the hypothesis that by-right approvals are faster. Faster approval can make multifamily development more feasible, which can in turn improve housing affordability. Analyses of approval pathways are often confounded by project size and complexity, but we exploited a provision in the Los Angeles Transit-Oriented Communities (TOC) program that allowed many large projects to use by-right approval. Using data from roughly 350 multifamily projects permitted in Los Angeles (CA) from January 2018 through March 2020, we compared approval timelines for both by-right and discretionary projects. We found that by-right projects were permitted 28% faster than discretionary projects, controlling for project and neighborhood characteristics. By-right projects also had less variance in their approval times, suggesting that by-right approval offers not just more speed but more certainty.

Takeaway for practice:
Planners should create more opportunities for multifamily housing to be permitted by right. Despite some selection bias in our study, evidence from the TOC program suggests that creating a by-right option would accelerate approval time and thus substantially benefit housing production. The faster approval timelines, moreover, have been accompanied by an increase in average project size and the number of units reserved for low-income households.

other

Working Paper: How Does Traffic, or the Fear of it, Affect Housing Affordability? Examining the Effect of Traffic Impact Analysis on Housing Production and Affordability

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Traffic impact analysis (TIA), which estimates the traffic impacts of proposed land development, tends to bias against higher-density developments in urban areas where traffic is often congested and travel alternatives plentiful. This has important implications for housing supply and affordability, suburban sprawl, and private vehicle dependence. The research team examines the understudied implication of TIA on housing by drawing on empirical evidence from distinct bodies of research in the transportation and land use planning literature to describe the mechanisms through which TIA may affect housing market conditions. The researchers conclude that TIAs likely have negative effects on urban housing production and affordability.

published journal article

Traffic Trumps All: Examining the Effect of Traffic Impact Analyses on Urban Housing

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Traffic impact analysis (TIA), which estimates the nearby traffic effects of proposed land development, tends to bias against higher-density developments in urban areas where traffic is often heavy and travel alternatives plentiful. This has important implications for housing supply and affordability, suburban sprawl, and private vehicle dependence. We examine the understudied implications of TIA on housing by drawing on empirical evidence from distinct bodies of research in the transportation and land use planning literature to describe the mechanisms through which TIA may affect housing markets. We conclude that TIAs likely have negative effects on both urban housing production and affordability.

policy brief

Traffic Trumps All: Examining the Effect of Traffic Impact Analyses on Urban Housing

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Traffic impact analyses (TIA) are widely used by local governments to assess the traffic impacts of proposed land use developments. TIAs are often measured in terms of expected changes to traffic flows through nearby intersections using a metric called “level of service” (LOS). This process tends to be biased against higher-density developments in urban areas where traffic is already congested and travel alternatives are plentiful. Researchers have found that the projected traffic impacts of developments in already built-up areas tend to be overestimated, which leads to higher traffic impact fees and related costs associated with the TIA process. Often, local residents use such analyses as evidence to oppose new developments on traffic grounds. The result is that TIAs can help discourage new housing production in built-up areas where demand is greatest, which likely exacerbates the housing affordability crises in places like California.In essence, the logic of TIAs is that the human activities and the built environment in cities should vary to keep nearby traffic flowing smoothly. The fundamental problem with LOS-based TIAs is that they measure vehicle mobility and not the more fundamental goals of economic and social accessibility. While California has been a national leader in changing the metric by which traffic impacts are evaluated under the California Environmental Quality Act, from LOS to vehicle miles of travel effects, LOS-based analyses of development proposals are still typically conducted by local governments — even in the Golden State.This study reviewed and synthesized research on TIAs and their effects on land use planning, and found that mobility-focused transportation planning likely contributes to the housing affordability crisis plaguing many places. Further, research shows that gradually shifting away from mobility-centered metrics, like LOS, and toward more accessibility-centered evaluation tools, will enable more comprehensive assessments of development impacts, which could help ease California’s housing affordability crisis.

policy brief

Environmental Reviews Fail to Accurately Analyze Induced Vehicle Travel from Highway Expansion Projects

Publication Date

January 1, 2021

Author(s)

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Induced travel is a well-documented effect in which expanding highway capacity increases the average travel speed on the highway, which in turn reduces the perceived “cost” of driving and thereby induces more driving. This increase in vehicle miles traveled (VMT) increases congestion (often back to pre-expansion levels) and air pollutant emissions, reducing or eliminating the purported benefits of the expansion. Yet highway expansion projects continue to be proposed across California, often using congestion relief—and sometimes greenhouse gas reductions—as a justification for adding lanes. These rosy projections about the benefits of highway expansion projects indicate that the induced travel effect is often not fully accounted for in travel demand models or in the projects’ environmental review process.With this problem in mind, researchers at the University of California, Davis developed an online tool to help agencies estimate the VMT induced annually by adding lanes to major roadways in California’s urbanized counties. The researchers also applied the calculator to estimate the vehicle travel induced by five highway expansion projects in California that had gone through environmental review within the past 12 years. They then compared their estimates with the induced travel analysis completed for the projects’ actual environmental impact assessments. This policy brief summarizes findings from that research, along with policy implications.View the NCST Project Webpage

Pandemic-related Shifts in Work, Travel, and Transit Use: Implications for Public Policy

Status

In Progress

Project Timeline

July 1, 2022 - October 31, 2023

Principal Investigator

Project Team

Areas of Expertise

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

Campus(es)

UC Davis, UCLA

Project Summary

While the COVID-19 pandemic dramatically affected travel and transportation systems, driving has largely returned to pre-pandemic levels, even as a significantly larger share of the workforce works from home full- or part-time. However, there have been significant changes in the timing and patterns of car travel since before the pandemic. Moreover, public transit systems have been especially hard hit, and riders have proven slow to return. While transit use by those unable to drive (who are more likely poor, immigrants, people of color, and/or disabled) has substantially recovered since the shutdowns in the spring of 2020, daily commuting to and from major employment centers collapsed and is just beginning to recover. The shifts in motor vehicle travel and the more dramatic changes in public transit use are both likely related to workplace changes, as the number of remote and hybrid workers has increased. The longer-term effects of the pandemic on travel remain uncertain, as do the appropriate policy responses to changing traffic patterns broadly, and to depressed transit ridership specifically. Public transit is a key transportation pillar of California’s climate and equity goals, which will be harder to meet with driving up and transit riding down.

To examine late-pandemic shifts in trip timing, this project analyzed smartphone location data to track the location and timing of vehicle trips on streets and highways in Greater Los Angeles. Specifically, this study compares the average number of trip origins for each hour of the day in all 10,783 census block groups in Imperial, Los Angeles, Orange, Riverside, San Bernardino, and Ventura counties in October 2019 and October 2021. The project then estimated a series of statistical models to examine the factors associated with both the levels of and changes in the timing of afternoon peak-period trip-making. Following an initial analysis, this project focused on shifts in early (12 p.m.–3:59 p.m.) and late (4 p.m.–7:59 p.m.) afternoon trip-making between fall 2019 and fall 2021. The primary data comes from StreetLight, a location analytics company that provides travel datasets collected from mobile phones, GPS receivers, and other network-enabled devices. This data was augmented with information from the U.S. Census, Longitudinal Employer-Household Dynamics Origin and Destination Employment Statistics (LODES), and the U.S. Department of Education.