Skip to main content
eScholarship
Open Access Publications from the University of California
Policy briefs from ITS researchers.
Cover page of Millennial Travelers Are More Multimodal than Older Travelers, but This Trend Might Change as They Age

Millennial Travelers Are More Multimodal than Older Travelers, but This Trend Might Change as They Age

(2021)

Millennials, those who were born between the early 1980s and the late 1990s, tend to have different travel patterns than the members of the preceding generations when they were at the same age. Among various dimensions of millennial travel, multimodality—the use of multiple travel modes— has important implications for transportation sustainability. Prior research has found that members of this generation travel more by walking, bicycling, and riding public transit. Further, multimodal travelers are usually better informed about and more sensitive to level-of-service attributes of various modes than are habitual users of single modes (especially cars). Therefore, exploring trends in multimodality among millennials could inform policymakers’ efforts to encourage more sustainable travel modes for millennials and shed light on how they might respond to policy interventions.

Researchers at the University of California, Davis, compared millennials’ travel behavior to that of members of the preceding Generation X by analyzing data collected from 1,069 California commuters. The researchers analyzed the effects of individual attributes on the likelihood of different components of travel behavior, including multimodal travel. This policy brief summarizes the findings of that research and provides policy implications.

View the NCST Project Webpage

Cover page of Telecommuting Rates During the Pandemic Differ by Job Type, Income, and Gender

Telecommuting Rates During the Pandemic Differ by Job Type, Income, and Gender

(2021)

The onset of the COVID-19 pandemic caused massive travel disruptions across the country. Many people nationwide shifted to telework following stay-at-home orders, while those providing essential operations and services continued to travel to work. The pandemic’s impacts on travel behavior have complex environmental and equity implications. Telecommuting can be a means of decreasing vehicle miles traveled and greenhouse gas emissions associated with commuter travel and can reduce congestion during peak times. However, not all jobs can be performed from home. Policymakers and regulators who are considering policies to encourage telecommuting to achieve greenhouse gas reduction goals need to consider potential inequities that may arise or be intensified by these policies.

Researchers at the University of California, Davis examined the impacts of the COVID-19 pandemic on telecommuting patterns among various socio-demographic groups in the United States. During the early stages of the pandemic in Spring 2020 they reached out to households that had participated in previous longitudinal travel studies to measure changes in household activities, personal preferences, and travel patterns due to the pandemic. This policy brief summarizes the findings from that research and provides policy implications.

View the NCST Project Webpage

Cover page of Ridehailing Demand Is Resilient Among Low-Income Travelers During the COVID-19 Pandemic

Ridehailing Demand Is Resilient Among Low-Income Travelers During the COVID-19 Pandemic

(2021)

The COVID-19 pandemic has caused major shifts in the use of various means of travel, including ridehailing services (e.g., Uber or Lyft). Downward trends in ridehailing unsurprisingly emerged as lockdown orders reduced overall travel. The shock to the ridehailing industry came as the industry was experiencing considerable growth and facing increased regulatory control. Researchers at the University of California, Davis, examined how the COVID-19 pandemic has impacted the use of ridehailing and other travel behaviors among various sociodemographic groups. They conducted surveys prior to and during the early stages of the 2020 COVID-19 pandemic to measure changes in household activities, personal preferences, and travel patterns. The findings discussed in this policy brief are based on the analysis of the information provided by 1,274 respondents who participated in the survey both before the pandemic (2018- 2019) and during the early stage of the pandemic (spring 2020). 

View the NCST Project Webpage

Cover page of Partially Automated Vehicles Are Increasing Vehicle Miles Traveled

Partially Automated Vehicles Are Increasing Vehicle Miles Traveled

(2021)

Research is beginning to show that vehicle automation will encourage more driving because it substantially reduces driver workload, making driving more relaxing and less stressful. This will have environmental sustainability implications, given that vehicle electrification alone will not be sufficient to meet state and federal greenhouse gas reduction targets without reductions in vehicle miles traveled (VMT). Research on the effects of vehicle automation has been somewhat speculative because fully automated vehicles are not yet commercially available. But many automakers are already incorporating automated features such as adaptive cruise control and lane keeping assist into their vehicles. These features assist in driving tasks and reduce the “cost” of driving in much the same way fully automated vehicles promise to do. Researchers at UC Davis surveyed owners of partially automated electric vehicles in California to understand the impact of partial automation on VMT. The survey asked respondents about their use of partial automation systems including BMW Driving Assistant, Ford Co-pilot360, Honda Sensing, Nissan ProPilot Assist, Tesla Autopilot, and Toyota Safety Sense. The results of this study show that partial automation has the potential to cause large increases in VMT.

Cover page of Do Electricity Prices Affect Electric Vehicle Adoption?

Do Electricity Prices Affect Electric Vehicle Adoption?

(2021)

The operational costs of electric vehicles are lower than those of gas-powered vehicles. This advantage is often cited by manufacturers, advocates, and policy-makers as a significant benefit of driving electric vehicles. Yet, the question of how consumers value operational costs when purchasing an electric vehicle is largely unexplored. While prior research has suggested that gasoline prices are an important factor for conventional vehicle buyers, consumers may not have the same awareness of electricity prices as they do for salient gasoline prices. The question of whether consumers accurately assess the costs and benefits of using electricity as a transportation fuel has important implications for electric vehicle adoption and for achieving deep decarbonization of the transportation sector through electrification.

Cover page of Leveraging the California Highway Incident Processing System for Traffic Safety Policy and Research

Leveraging the California Highway Incident Processing System for Traffic Safety Policy and Research

(2021)

Accurate data on crashes and other traffic incidents are critical for analyzing the rates, costs, and causes of crashes, and for evaluating the effects of safety policies and engineering solutions. There are two official sources of data on traffic incidents in California: 1) the Statewide Integrated Traffic Records System (SWITRS),1 managed by the California Highway Patrol (CHP), which includes post-processed data on traffic incidents leading to human injury or death; and 2) Caltrans’ Performance Measurement System (PeMS),2 which includes data on traffic incidents as well as traffic counts, lane closures, and other information. Both databases draw from CHP incident reports that describe the location, conditions, and other important details and observations surrounding each incident. Traffic safety researchers rely heavily on both databases, but each has limitations. PeMS data are limited to state highways. Incident data can take months to appear in SWITRS and may omit crucial information.

Cover page of Ten Ways Transportation Agencies Can Improve Public Engagement with Diverse Communities

Ten Ways Transportation Agencies Can Improve Public Engagement with Diverse Communities

(2021)

Transportation agencies are recognizing the importance of undertaking robust public engagement, especially with historically disadvantaged communities. Many of these communities have been subject to redlining, division and demolition from highway construction or redevelopment efforts, and other forms of institutional discrimination perpetuated by civic agencies, including transportation departments. This history has fostered distrust, which makes current public engagement efforts challenging. This challenge is exacerbated by a lack of networks that might aid transportation practitioners in connecting with local residents.

Cover page of The Monetary and Non-Monetary Factors Influencing Travel Choices in an Automated, Shared, and Electric Vehicle Future

The Monetary and Non-Monetary Factors Influencing Travel Choices in an Automated, Shared, and Electric Vehicle Future

(2021)

The transportation system is undergoing three revolutions: vehicle automation, electrification, and shared mobility. While these are still nascent trends, studies suggest that they could become ubiquitous in the coming decades. How these revolutionary changes transpire will have significant implications for transportation sustainability. A key factor will be whether autonomous vehicles are deployed as shared cars that serve many travelers such as in ridesourcing or ridehailing fleets, or as privately owned vehicles that could dramatically increase vehicle miles traveled and associated environmental impacts. To anticipate how these revolutions will affect future transportation, and to develop policy to shape that future, it is important to understand the various factors that influence individuals’ travel choices. These choices include whether to travel alone or with others, and whether to use a private vehicle or a shared one. Some of these factors are monetary, such as the cost of fuel, insurance, and a driver, while others are non-monetary, such as the travel time, comfort, and reliability of each transportation option. The significance of these non-monetary factors is poorly understood and often ignored.

Researchers at the University of California, Davis developed a framework for considering the monetary and non-monetary costs of future travel choices and used existing research to develop interim values for several non-monetary travel choice factors. This policy brief summarizes the findings from that research and provides policy implications.

View the NCST Project Webpage

Cover page of Can Complete Streets Deliver on Sustainability?

Can Complete Streets Deliver on Sustainability?

(2021)

Complete streets are those designed not only for private vehicles, but also to enable safe access for all users, including pedestrians, bicyclists, motorists, and transit riders of all ages and abilities. Specific street designs vary based on the type of street. Complete streets are intended to improve non-motorized travel safety, reduce costs and environmental burdens, and create more livable, sustainable, and economically vibrant communities. Investment in complete streets projects is growing around the country with these goals in mind. However, there are limited data to verify the effectiveness of complete streets, and the indicators required for quantification of complete street performance are not yet agreed upon. Complete street sustainability indicators are important to assess whether a complete street conversion is achieving its goals and to support decision-making for complete street investment.

Researchers at the University of California, Davis and JCH Research used life cycle assessment, a modeling tool for evaluating a product or activity’s environmental impacts through all stages of its life, to quantify the environmental performance of complete streets. The researchers also reviewed the academic literature for social impact indicators, which have generally not been well developed in life cycle assessment applications. The researchers adapted these indicators to better consider equity, guided by interviews with a diverse set of stakeholders. Complete street typologies compiled from several sources were used to test and refine the life cycle assessment framework for complete street conversions. This policy brief summarizes the findings from that research.

View the NCST Project Webpage

Cover page of Why are Some California Consumers Abandoning Electric Vehicle Ownership?

Why are Some California Consumers Abandoning Electric Vehicle Ownership?

(2021)

California has set an ambitious goal of 100% zero-emission vehicle sales by 2035. Most consumer research to date has focused on understanding the factors influencing the initial purchase of plug-in electric vehicles (PEVs). But for the market introduction of PEVs, which include both battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs), to be successful, subsequent vehicle purchases by initial adopters need to continue to be PEVs rather than conventional vehicles. Discontinuance, the act of abandoning a new technology after once being an adopter, could make achieving California’s goal more challenging.

Researchers at the University of California, Davis surveyed California PEV buyers two to seven years after they first purchased their electric vehicle to understand whether they have continued to choose PEVs with subsequent purchases, and if not, what factors may have led to their discontinuance of the technology. This policy brief summarizes the findings from that research and provides policy implications.

View the NCST Project Webpage