research report

Green Charging of Electric Vehicles Under a Net-Zero Emissions Policy Transition in California

Abstract

California has many aggressive climate policies, primarily aimed at individual sectors. This study explores untapped policy opportunities for interactions between sectors, specifically between the transportation and the electricity grid. As electric vehicles become more prevalent, their impact on the electricity grid is directly related to the aggregate patterns of vehicle charging. Even without vehicle-to-grid services, shifting charging patterns can be a potentially important resource to alleviate issues such as renewable intermittency. This study compares, through modeling, projected emissions reductions from managed vs. unmanaged charging. The majority of emissions reduction in the light-duty transportation sector in California will come from electrification, with a cumulative 1 billion tons of CO2 reduction through 2045. Decarbonization of the current grid leads to an additional savings of 125 million tons of CO2 over the same time periodotential state policies to exploit synergies between transportation electrification and grid decarbonization could reduce cumulative emissions by another 10 million tons of CO2. These policies include strategic deployment of charging infrastructure, pricing mechanisms, standardizing grid interaction protocols, and supporting grid infrastructure requirements.

research report

All Is Not LOST: Tracking California’s Local Option Sales Tax Revenues for Transportation During the Pandemic

Abstract

The COVID-19 pandemic dramatically affected transportation systems, including the ability of localities to pay for them. The research team explores the effects of the pandemic and the associated economic turbulence on local option sales taxes (LOSTs), an increasingly common revenue source for transportation in California and across the U.S. LOSTs have many advantages over alternative finance instruments, and they can raise prodigious amounts of revenue. However, LOST funding relies on consumer spending. During times of economic weakness, spending and therefore LOST revenues will lag. This is precisely the pattern the team observed in California counties during the initial months of the pandemic. Fortunately for local transportation budgets, LOST revenues recovered after the initial economic shock of COVID-19, albeit at a lower level than they likely would have otherwise. LOST revenue trends during the pandemic were affected by national and regional economic conditions and government policy as well. This public health crisis illustrates both the pitfalls and resilience of LOSTs during economic downturns and recoveries. The lessons from the pandemic’s effects on LOSTs will be useful for policymakers and analysts in preparing for inevitable future economic fluctuations.

policy brief

Bike-Share in the Sacramento Region Primarily Substitutes for Car and Walking Trips and Reduces Vehicle Miles Traveled

Abstract

Dock-less, electric bike-share services offer cities a new transportation option with the potential to improve environmental, social, and health outcomes by increasing physical activity and reducing vehicle miles traveled (VMT) and related greenhouse gas emissions. But these benefits accrue only if bike-share use replaces car travel. If bikeshare pulls users from public transit, personal bikes, or walking, the benefits will be limited. Little is known about the factors influencing whether bike-share substitutes for driving. Understanding the degree to which and under what circumstances bike-share use reduces car travel can inform cities’ efforts to meet VMT reduction goals set under California’s Sustainable Communities and Climate Protection Act of 2008 (Senate Bill 375). Researchers at the University of California, Davis collected user surveys and system-wide trip data from a Sacramentoarea dockless e-bike-share program in 2018 and 2019 to examine factors influencing travel mode substitution and estimated system-wide VMT reductions caused by bikeshare use. They developed a model to examine factors influencing bike-share demand and estimated potential VMT reductions for hypothetical expanded service scenarios.

research report

Where Ridehail Drivers Go Between Trips: Trading off Congestion and Curb Availability?

Abstract

The research team analyzed what ride-hail drivers do when out of service between paid trips. The paper utilizes a dataset of 5.3 million trips in San Francisco and partitions each out-of-service trip into cruising, repositioning, and parking segments. We find that repositioning accounts for nearly two-thirds (63%) of the time between trips, with cruising and parking accounting for 23% and 14% respectively (these figures exclude short trips). The regression models suggest that drivers tend to make reasonable choices between repositioning and parking, heading to high-demand locations based on the time of day. However, we also find suggestive evidence of racial bias, supporting previous studies of both taxis and ride-hailing that indicate that drivers tend to avoid neighborhoods with high proportions of residents of color.

research report

How Dock-less Electric Bike Share Influences Travel Behavior, Attitudes, Health, and Equity: Phase II

Abstract

Dock-less, electric bike-share services offer cities a new transportation option with the potential to improve environmental, social, and health outcomes. But these benefits accrue only if bike-share use replaces car travel. The purpose of this study is to examine factors influencing whether bike-share substitutes for driving and the degree to which and under what circumstances bike-share use reduces car travel. Major findings in this report include (1) bike-share in the Sacramento region most commonly substitutes for car and walking trips, (2) each bike in the Sacramento bike-share fleet reduces users’ VMT by an average of approximately 2.8 miles per day, (3) areas with a higher proportion of low-income households tend to use bike-share less, (4) bike-share availability appears to induce new trips to restaurants and shopping and for recreation, (5) bike-share trips from commercial and office areas were more likely to replace walking or transit trips, while bike-share trips from non-commercial areas (and trips to home or restaurants) were more likely to replace car trips, (6) expanding the bike-share service boundary at the same fleet density decreases system efficiency and VMT reductions per bike. The result suggests the need for an efficient rebalancing strategy specific to areas by time of day to increase the service efficiency and its benefits. Further analysis of the data used in this study to examine questions such as how bike share can improve transit connections and factors inducing bike use at the individual level will contribute to the development of more robust models and provide additional insights for bike share operation strategies and policy implementation.

published journal article

Viewpoint: Turning streets into housing

Abstract

I argue that wide residential streets in US cities are both a contributor to homelessness and a potential strategy to provide more affordable housing. In residential neighborhoods, subdivision ordinances typically set binding standards for street width, far in excess of what is economically optimal or what private developers and residents would likely prefer. These street width standards are one contributor to high housing costs and supply restrictions, which exacerbate the housing affordability crisis in high-cost cities. Planning for autonomous vehicles highlights the overprovision of streets in urban areas. Because they can evade municipal anti-camping restrictions that restrict the use of streets by unhoused people, autonomous camper vans have the ability to blur the distinction between land for housing and land for streets. I propose two strategies through which excess street space can accommodate housing in a formalized way. First, cities could permit camper van parking on the right-of-way, analogous to liveaboard canal boats that provide housing options in some UK cities. Second, extending private residential lots into the right-of-way would create space for front-yard accessory dwelling units.

research report

Emissions Impact of Connected and Automated Vehicle Deployment in California

Abstract

This study helps understand how the anticipated emergence of autonomous vehicles will affect various aspects of society and transportation, including travel demand, vehicle miles traveled, energy consumption, and emissions of greenhouse gases and other pollutants. The study begins with a literature review on connected and automated vehicle (CAV) technology for light-duty vehicles, the factors likely to affect CAV adoption, the expected impacts of CAVs, and approaches to modeling these impacts. The study then uses a set of modifications in the California Statewide Travel Demand Model (CSTDM) to simulate the following scenarios for the deployment of passenger light-duty CAVs in California by 2050: (0) Baseline (no automation); (1) Private CAV; (2) Private CAV + Pricing; (3) Private CAV + Zero emission vehicles (ZEV); (4) Shared CAV; (5) Shared CAV + Pricing; (6) Shared CAV + ZEV. The modified CSTDM is used to forecast travel demand and mode share for each scenario, and this output is used in combination with the emission factors from the EMission FACtor model (EMFAC) and Vision model to calculate energy consumption and criteria pollutant emissions. The modeling results indicate that the mode shares of public transit and in-state air travel will likely sharply decrease, while total vehicle miles traveled and emissions will likely increase, due to the relative convenience of CAVs. The study also reveals limitations in models like the CSTDM that primarily use sociodemographic factors and job/residence location as inputs for the simulation of activity participation and tour patterns, without accounting for some of the disruptive effects of CAVs. The study results also show that total vehicle miles traveled and vehicle hours traveled could be substantially impacted by a modification in future auto travel costs. This means that the eventual implementation of pricing strategies and congestion pricing policies, together with policies that support the deployment of shared and electric CAVs, could help curb tailpipe pollutant emissions in future scenarios, though they may not be able to completely offset the increases in travel demand and road congestion that might result from CAV deployment. Such policies should be considered to counteract and mitigate some of the undesirable impacts of CAVs on society and on the environment.

published journal article

Characteristics and Experiences of Ride-Hailing Drivers with Electric Vehicles

Abstract

Electrification of transportation network companies (TNCs), such as Uber and Lyft, can produce social and environmental benefits from reduced vehicle emissions and enhanced implementation of renewable electricity as well as private benefits to drivers via reduced vehicle fuel and maintenance costs compared to conventional vehicles. We conducted a survey of plug-in electric vehicle (PEV) drivers on the Uber platform in the US. This paper describes these drivers and their experiences to further understanding of motivations for and barriers to PEV adoption among TNC drivers. The TNC-PEV drivers in this sample clearly recognized, and were largely motivated by, economic benefits of fuel and maintenance savings, thus, increased net earnings, associated with using a PEV to provide ride-hailing services rather than a conventional internal combustion engine vehicle. Most drivers reported charging their PEV every day, most often at home and overnight. This is true even of those with plug-in hybrid electric vehicles (PHEVs) that can run on gas if not charged. Increased electric driving range topped the list of drivers’ wishes to better support PEVs on TNCs, and range limitations topped the list of reasons why PHEV drivers did not opt for a battery electric vehicle (BEV; that runs exclusively on electricity). The second most common wish among all PEV drivers was for more charger locations.