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Open Access Publications from the University of California
Cover page of Experiencing Pilot Demonstrations Helps Individual Acceptance of Self-Driving Shuttles

Experiencing Pilot Demonstrations Helps Individual Acceptance of Self-Driving Shuttles

(2020)

Higher-occupancy self-driving shuttles could bring about the benefits of vehicle automation—improved safety, parking cost savings, greater mobility to those who cannot drive, and stress relief for drivers. At the same time, these shuttles would not bring the potential drawbacks of self-driving vehicle ownership, such as increases in vehicle miles traveled and associated energy use. Because they can only currently operate in relatively simple and closed environments, self-driving shuttles are likely to be deployed earlier than personal self-driving vehicles in open road environments. However, acceptance of the new technology remains uncertain. Whether people will use these services will be largely influenced by their attitudes toward self-driving technology.

Researchers at the University of California, Davis surveyed residents and employees of the West Village area of the UC Davis campus during the three-month pilot deployment of a self-driving, electric shuttle to understand attitudes toward self-driving technology. The researchers then applied existing theories of technology adoption to model how attitudes of residents and employees influenced their acceptance of the shuttle service. This policy brief summarizes findings from that research and provides policy implications of self-driving shuttles.

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Cover page of Understanding Wildlife Behavioral Responses to Traffic Noise and Light to Improve Mitigation Planning

Understanding Wildlife Behavioral Responses to Traffic Noise and Light to Improve Mitigation Planning

(2020)

As roads and other developed land uses proliferate, the resulting habitat fragmentation and loss of wildlife connectivity hinder animals’ ability to forage, establish new territories, and maintain genetic diversity. Wildlife crossing structures such as culverts and bridges theoretically can reduce these impacts by allowing species to effectively cross highways. However, previous research has shown that traffic presence and density can disrupt wildlife use of highway crossing structures, and that noise and light from human activities can affect animal behavior. Researchers at the University of California, Davis, Road Ecology Center measured traffic noise and light levels and placed motion- and heat-triggered cameras at 26 bridges and culverts along four interstate highways, 11 state highways and one major county road across California. The presence and behavior of animals at these highway crossing structures were compared to those detected at sites unaffected by roads to understand the effects of noise and light from a highway on wildlife behavior. This policy brief summarizes findings from that research and provides policy implications.

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Cover page of Best Practices for Electric Vehicle Cost Calculator User Interfaces

Best Practices for Electric Vehicle Cost Calculator User Interfaces

(2020)

One of the potential consumer benefits of electric vehicles (EVs) is lower fuel and maintenance costs compared to internal combustion engine vehicles (ICEVs). Consumers tend to have difficulty recognizing these cost benefits, however, because of the complexity of comparing gasoline and electricity prices, and comparing long-term operating savings with EV purchase premiums. Online vehicle cost calculators may help consumers navigate this complexity by providing tailored cost estimates and enabling comparisons across vehicles. Of the several vehicle cost calculators available online, functionalities range widely. No existing research establishes the functionalities and features that determine the usefulness of vehicle cost calculators in promoting EV adoption. Researchers at the University of California, Davis drew upon a systematic review of vehicle cost calculators and findings from multiple user experience studies to articulate best practices for the user interface design of effective vehicle cost calculators. The researchers categorized best practices as those related to the vehicle cost calculator use cases, outputs, user experience, and user inputs.

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Cover page of High Percentages of Reclaimed Asphalt Affect the Performance of Asphalt Binder

High Percentages of Reclaimed Asphalt Affect the Performance of Asphalt Binder

(2020)

More than 90 percent of the road and highway network in the United States is paved with asphalt concrete. Maintenance and periodic rehabilitation require a continuous supply of aggregates and asphalt binder, both of which are becoming increasingly scarce and expensive. Recycling and reusing these resources can reduce costs and improve sustainability. The most common recyclable material used in road construction is reclaimed asphalt pavement (RAP), which is milled asphalt surface layers that have been removed from existing pavements before new asphalt overlay is placed. Reclaimed asphalt roofing shingles (RAS) are another potential source of asphalt binder.

There is growing interest in allowing significantly higher percentages of RAP and RAS in asphalt mixes used on state and local roadways. However, making this change has raised concerns regarding how these composite binders may influence the performance and durability of asphalt mixes, depending on the blends of different virgin and reused binders. Researchers at the UC Pavement Research Center investigated the use of higher percentages of RAP and RAS as a partial replacement for the virgin binder in new asphalt mixes and their effect on pavement performance in California. This research brief summarizes findings from that study.

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Cover page of Emissions Information Can Prompt Travelers to Purchase Greener Flights

Emissions Information Can Prompt Travelers to Purchase Greener Flights

(2020)

This policy brief summarizes findings and policy implications from a study in which researchers at the University of California, Davis, surveyed over 450 UC Davis faculty, researchers, and staff, and asked them to choose among hypothetical flight options for domestic and international university-related business trips. The hypothetical flight options were developed using actual data on UC Davis employee air travel and available flights. The survey prominently presented emissions estimates for different flight alternatives alongside price, with the lowest-emissions option labeled “greenest flight”. Researchers then estimated the effect that changing the current UC Davis flight-search interface to prominently display emissions, label the greenest flight choice, and present an alternative departure airport could have on the emissions and costs of business-related air travel.

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Cover page of Reducing Car Dependence Has Economic, Environmental, and Social Benefits

Reducing Car Dependence Has Economic, Environmental, and Social Benefits

(2020)

Californians live in a car-dominant society. Decades of transportation and land use planning practices have created communities in which driving is a virtual necessity to access most destinations. Personal vehicles provide mobility benefits, but they also have many negative financial, public health, environmental, and social impacts. Technological innovations such as vehicle electrification can lessen some, but not all, of these impacts. A more comprehensive approach is to shape communities in a manner that gives people viable options other than a personal vehicle—such as walking, bicycling, or transit—to get where they need to go.

Researchers at UC Davis reviewed published studies to summarize the range of household- and community-level benefits that can be realized by reducing car dependence in California. This policy brief summarizes the findings of that work.

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Cover page of Bike Lanes and Slow Car Speeds Can Improve Bicycling Comfort for Some (But Not All) People

Bike Lanes and Slow Car Speeds Can Improve Bicycling Comfort for Some (But Not All) People

(2020)

Transportation planners in cities across the country are trying to increase bicycling to achieve mobility, public health, and environmental goals. For bicycling to become a mainstream travel mode, however, riders must feel safe and comfortable in the bicycling environment. Thus, cities are changing transportation infrastructure to provide more bicycling-friendly streets.

It remains unclear exactly how much infrastructure change is needed to make potential cyclists feel comfortable enough to bicycle regularly. To better understand what road characteristics contribute to more comfortable bicycling, researchers at UC Davis surveyed 3,089 travelers to the UC Davis campus to measure perceived comfort of bicycling in different road environments using video recordings of 25 urban and rural roads from the San Francisco Bay Area. This policy brief summarizes findings from that research, which provide guidance for communities aiming to increase bicycling.

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Cover page of Automated Vehicles are Expected to Increase Driving and Emissions Without Policy Intervention

Automated Vehicles are Expected to Increase Driving and Emissions Without Policy Intervention

(2020)

Researchers at UC Davis explored what an automated vehicle future in the San Francisco Bay Area might look like by simulating:

1) A 100% personal automated vehicle future and its effects on travel and greenhouse emissions.

2) The introduction of an automated taxi service with plausible per-mile fares and its effects on conventional personal vehicle and transit travel.

The researchers used the Metropolitan Transportation Commission’s activity-based travel demand model (MTC-ABM) and MATSim, an agent-based transportation model, to carry out the simulations. This policy brief summarizes the results, which provide insight into the relative benefits of each service and automated vehicle technology and the potential market for these services.

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Cover page of Ride-Hailing Holds Promise for Facilitating More Transit Use in the San Francisco Bay Area

Ride-Hailing Holds Promise for Facilitating More Transit Use in the San Francisco Bay Area

(2020)

Increasing transit use has many benefits, including reducing traffic congestion and greenhouse gas (GHG) emissions. However, riders need to be able to get to a station in order to use transit. Walking is an option only for those within a limited radius of a station. Driving to a station may be feasible for some, but providing sufficient parking can be expensive and land intensive. The rise of ride-hailing companies such as Uber and Lyft presents a new opportunity for bridging the “first-mile” gap to high quality transit. Transit agencies are beginning to launch pilot projects to test public-private partnerships with ride-hailing companies to increase access to transit.

This policy brief summarizes findings from researchers at UC Davis who used existing modeling tools and data to understand the potential market demand for a first-mile transit access service in the San Francisco Bay Area. They modeled the likelihood of commuters who drive alone to switch to using ride-hailing and the Bay Area Rapid Transit (BART) rail system to get to work based on travel time, cost, and distance to a BART station. They explored the magnitude of change in overall travel time and cost for travelers who switch from driving alone to using ride-hailing and BART, as well as potential changes to vehicle miles traveled (VMT) and GHG emissions at both the regional and station level.

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Cover page of Shared-Use Mobility Services Can Improve Access and Reduce Costs in Rural Disadvantaged Communities

Shared-Use Mobility Services Can Improve Access and Reduce Costs in Rural Disadvantaged Communities

(2020)

Low-income rural residents, especially those who do not own a car, have limited transportation options for accessing jobs, health care, education, healthy food, and other basic services. Rural transit service is often expensive, infrequent, and hard to access because of long travel distances and low development densities. Transit providers face very high operating costs of fixed-route and dial-a-ride transit services because of low farebox recovery rates.

Shared-use mobility services such as ridehailing and carsharing largely serve major metropolitan areas. However, rural governments are beginning to consider whether these types of services may be able to augment existing transit services while providing cost-effective transportation access to rural residents.

This policy brief summarizes findings from a UC Davis study in which researchers compared the cost-effectiveness of existing inter-city transit service in rural disadvantaged communities in California’s San Joaquin Valley to hypothetical ridesharing and carsharing services. The researchers also reviewed existing shared-use mobility pilots and consulted with experts in shared mobility and local transportation planning to develop concepts for future shared mobility pilot programs in the San Joaquin Valley.

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