UC Davis Institute of Transportation Studies

Carbon emissions targets require large reductions in greenhouse gases (GHGs) in the near-to mid-term, and the transportation sector is a major emitter of GHGs. To understand potential pathways to GHG reductions, this project developed the U.S. Transportation Transitions Model (US TTM) to study various scenarios of zero-emission vehicle (ZEV) market penetration in the U.S. The model includes vehicle fuel economy, vehicle stock and sales, fuel carbon intensities, and costs for vehicles and fuels all projected through 2050. Market penetration scenarios through 2050 are input as percentages of sales for all vehicle types and technologies. Three scenarios were developed for the U.S.: a business as usual (BAU), low carbon (LC), and High ZEV scenario. The LC and High ZEV include rapid penetration of ZEVs into the vehicle market. The introduction of ZEVs requires fueling infrastructure to support the vehicles. Initial deployments of ZEVs are expected to be dominated by battery electric vehicles. To estimate the number and cost of charging stations for battery electric trucks in the mid-term, outputs were used from a California Energy Commission (CEC) study projecting the need for chargers in California. The study used the HEVI-Pro model to estimate electrical energy needs and number of chargers for the truck stock in several California cities. The CEC study outputs were used along with the TTM model outputs from this study to estimate charger needs and costs for six U.S. cities outside California. The LC and High ZEV scenarios reduced carbon emissions by 92% and 94% in the U.S. by 2050, respectively. Due to slow stock turnover, the LC and High ZEV scenarios contain significant numbers of ICE trucks. The biomass-based liquid volume reaches 70 (High ZEV) to 80 (LC) billion GGE by 2045. For the cities in this study, the charger cost ranges from $5 million to $2.6 billion in 2030 and from roughly $1 billion to almost $30 billion in 2040.

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“Complete streets” is a design concept for primarily urban streets and intersections (existing and/or new) intended to encourage active transportation by bicyclists and pedestrians by making streets safer, convenient, and attractive for active transportation; motorized transportation and parking are also accommodated in the design concept. The social and economic performance indicators included in the social life cycle assessment (SLCA) framework that was used in this project provide a great deal of insight into specific and different potential benefits of a given complete streets project. The SLCA framework is based on five categories of concerns and 17 performance measures or indicators. The indicators were tested in the project and evaluated for final recommendations for use in future studies. The results are compared with the existing streets that were configured to be vehicle-centric. The case studies were solicited in more and less advantaged neighborhoods so that the framework could also be evaluated in different contexts. Use of the CalEnviroScreen tool from the California Environmental Protection Agency was also investigated to assess the exposure of neighborhoods and their vulnerability to environmental impacts in conjunction with the performance indicators when evaluating the potential benefits for disadvantaged neighborhoods (also called priority population areas). As was found in the preceding study, the primary environmental impacts come from the use stage, namely changes in vehicle travel and changes in vehicle speeds from complete street design features. Recommendations are made for dropping some indicators because of difficulties collecting data or interpreting the results, modifications of other indicators, and adding some new indicators to fill important gaps.

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Congestion pricing (CP) is widely considered to have significant potential for effectively reducing vehicle miles traveled, reducing emissions, and providing a reliable revenue source for transportation investments. This study evaluated cities interested in CP—five in the U.S. (Boston, Los Angeles, New York, San Francisco, Seattle) and two in other countries (Vancouver, Canada, and Auckland, New Zealand). This study examines the following features of a CP system for each of these cities: 1) duration of CP investigations, 2) equity mitigations, 3) range of alternatives considered, 4) public engagement, and 5) importance of emissions reductions. Timelines are impossible to predict with certainty, but New York and Auckland appear closest to implementation. Vancouver, San Francisco, and Seattle are well into the process; and Boston and Los Angeles are early in the process. Other key findings include that most of the cities start considering a range of options before narrowing down to comparing more detailed CP systems. Vancouver and San Francisco have made public engagement a cornerstone of their plan development, using polls and workshops to finetune the details of their CP proposals. In contrast, Auckland, while still engaging with stakeholders and experts for guidance, has mainly focused on how to ensure public support and understanding of the proposals they recommend. In terms of equity, discounts are a common and primary strategy proposed among the cities, but some also develop a more comprehensive set of equity policies to accompany a CP system.

In rural areas, cost-effective transit service is challenging due to greater travel distances, lower population densities, and longer travel times than in cities. As a result, the people who rely on public transit contend with infrequent and slow service, and keeping a sufficient number of personal vehicles in reliable working order can be prohibitively expensive for low-income families. UC Davis partnered with the eight San Joaquin Valley Metropolitan Planning Organizations to identify and support development of three innovative mobility pilot concepts for the region. The first pilot is an electric vehicle (EV) carsharing service known as Míocar, located in affordable housing complexes in eight rural communities in Tulare and Kern counties. The second is a volunteer ridesharing service, known as VOGO, which supplements existing transit services in transport-disadvantaged rural areas in San Joaquin and Stanislaus counties. The third is a Mobility-as-a-Service (MaaS) platform that allows planning and payment for fixed and demand-responsive transit services, including VOGO, in San Joaquin and Stanislaus counties. These pilots seek to (a) provide improved access to destinations for individuals with limited transportation alternatives, (b) and achieve greenhouse gas reductions through mode shifts from traditional internal combustion vehicles to EVs, ridesharing, and fixed transit. This report presents the methods and results for “before” and “after” evaluations conducted by UC Davis researchers to assess the performance and impacts of each pilot. The evaluations incorporate service usage data including telematics and MaaS application data, and survey data collected from pilot participants, to assess the programs beginning with pilot launch (2019 and2020) until November 2021. The results provide insights into participant characteristics and barriers to transportation, travel behavior, trip planning activities, and the extent to which the pilots addressed the travel needs of their target populations region.

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Electric bicycle charging facilities that support active mobility and public transit connectivity can play a significant role in the global transition to low-carbon energy. Design of an electric bicycle solar charging station can combine solar technology, light transportation infrastructure, and civic place-making to provide the public an opportunity to recharge their mobile electronics, e-bikes, or e-scooters. The proposed station design reimagines public space by providing a shaded seating area during the day and a vibrant, LED-lit space at night. Four solar panels and a battery bank extend the station’s charging capacity into the night. The goal of this project is to serve as an off-grid energy power supply and environmental information center, with interactive displays of the solar station operation and an LED display of local air quality.

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Microtransit is an emerging, technology-enabled, on-demand transportation mode whereby small shuttles provide shared rides through flexible routing and scheduling in response to customers’ requests for rides. Given its potential to address the equity and accessibility needs of the public, public transportation agencies are experimenting with this service to fill gaps in traditional transportation in the US. However, why some people are interested in microtransit while others are not remains an open question. For people who have never used it, what factors could work as facilitators or barriers in their willingness to adopt microtransit? Who are the early adopters of microtransit? Guided by the theory of planned behavior, this study aims to fill the gap in knowledge by conducting a large-scale survey of microtransit adopters and users of other means of transportation in the Sacramento area of California in 2021. This study focuses on the microtransit service SmaRT Ride (SR), operated by the Sacramento Regional Transit District (SacRT). Focus groups and interviews were conducted before the largescale online survey to gather preliminary information, help develop survey questions, and improve understanding of research findings, given the novelty of microtransit. Discrete choice models, including binary logit and ordered logit models and latent class analysis, were employed to explore barriers to and facilitators of SR adoption, willingness to use it, and underlying subgroups of early adopters. Important findings include that people who like fixed-route transit are less likely to adopt microtransit. Social support plays an important role in explaining the willingness to use microtransit. The analysis reveals three salient classes of microtransit users: travel time savers with environmental awareness, riders with a neutral mindset, and pro-SR and travel cost savers.

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While micromobility services (e.g., bikeshare, e-bike share, e-scooter share) hold great potential for providing clean travel, estimating the effects of those services on vehicle miles traveled and reducing greenhouse gases is challenging. To address some of the challenges, this study examined survey, micromobility, and transit data collected from 2017 to 2021 in approximately 20 U.S. cities. Micromobility fleet utilization ranged widely from 0.7 to 12 trips per vehicle per day, and the average trip distance was 0.8 to 3.6 miles. The median (range) rates at which micromobility trips substituted for other modes were 41% (16–71%) for car trips, 36% (5–48%) for walking, and 8% (2–35%) for transit, 5% (2–42%) for no trip. In most cities, the mean actual trip distance was approximately 1.5 to 2 times longer than the mean distance of a line connecting origin to destination. There was a weak and unclear connection between micromobility use and transit use that requires further study to more clearly delineate, but micromobility use had a stronger positive relationship to nearby rail use than to nearby bus use in cities with rail and bus service. The COVID-19 pandemic led to more moderate declines in docked than in dockless bike-share systems. Metrics that would enable better assessment of the impacts of micromobility are vehicle miles traveled and emissions of micromobility fleets and their service vehicles, and miles and percentage of micromobility trips that connect to transit or substitute for car trips.

California has set a goal of reaching 100% zero emission vehicle (ZEV) sales by 2035. Most ZEV sales to date have been battery electric vehicles (BEVs) or plug-in hybrid electric vehicles (PHEVs), while fuel cell electric vehicles (FCEVs) make up only a small portion of ZEV sales. The market for FCEVs may be partially constrained because, unlike BEVs and PHEVs, they cannot use any existing infrastructure. This research investigates FCEV drivers use of hydrogen stations in California (of which there are 47 in operation) with the goal of informing the development of hydrogen infrastructure. Hydrogen station use was studied using results from a 2017 survey of 395 fuel cell electric vehicle (FCEV) owners and a 2018 survey of 328 FCEV owners. The results show FCEV drivers use on average 2.4 hydrogen stations. The average shortest distance FCEV owners would need to travel from home, work, or their commute to a hydrogen refueling station was 10 miles. Those whose most-used station was not the closest station available were more likely than those whose most-used station was the closest to use renewable hydrogen, suggesting that some drivers may prefer renewable hydrogen. Currently the percentage of California census block groups with one, two, and three hydrogen stations within 10 miles of households are 52.4%, 25.6%, and 22.5%; these census block groups are concentrated primarily in large metropolitan areas. Finally, 70% of FCEV owners said they would not have purchased the vehicle if their primary station had not been available, pointing the importance of station availability to FCEV adoption.

Transit agencies are looking for ways to save costs and improve transit rider experiences. One strategy to accomplish this is to replace legacy payment systems that accept cash and in-network agency-issued tickets or cards with fully digital open-loop payments systems, which accept all debit, credit, and mobile payments and are more readily interoperable between different transit agencies and shared mobility operators. This transition will not come without confronting a number of equity and logistical challenges to ensure all riders benefit from this transition. The state of California’s California Integrated Travel Project (Cal-ITP) aims to help transit agencies make this digital payment transition. Researchers at UC Davis partnered with Cal-ITP to explore this question: how can California transit agencies modernize fare payment while ensuring transit systems are open and accessible to un-and underbanked riders? Researchers collected 200+ intercept surveys in the Davis-Sacramento-Woodland area of California to assess the potential for un-and underbanked passengers to use digital payment tools, such as contactless cards, and smartphone-based apps. This research finds that among unbanked riders who typically pay with cash, more than half of respondents would be open to paying with a prepaid debit card or a prepaid government-issued debit card, and about a third are open to paying with a mobile phone.

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