Institute of Transportation Studies at UC Berkeley

In a world where people are increasingly shifting from internal combustion engine (ICE) vehicles to electric vehicles, revenue from state fuel taxes has continued to decline. This has prompted policymakers to consider alternative mechanisms to fund transportation infrastructure, including the introduction of a Vehicle Miles Travelled (VMT) fee. However, these changes may have distributional consequences. This study examines the geographical equity impacts of a VMT fee on residents of five cities in the San Francisco Bay Area and compares the financial burdens of a VMT fee and the existing fuel tax for households living in urban and rural settings. Household-level travel, income, and residential location data were obtained from the 2017 National Household Travel Survey. Four scenarios were evaluated: the current fuel tax, a static VMT fee, a dynamic VMT fee with modified elasticities, and a dynamic VMT fee using raw elasticities. Equity was assessed using the Gini Index. Results show that rural households face consistently higher burdens across all scenarios. The static VMT fee produces small changes relative to the fuel tax, while the dynamic scenarios increase financial burdens; especially for lower-income households due to behavioral adjustments. Overall, a VMT fee can serve as an alternative to the fuel tax, but behavioral responses and distributional differences remain important policy considerations.

The Vehicle Weight Safety Study provides supporting analysis for the California Transportation Commission’s study on therelationship between vehicle weight and road user injury and roadway degradation required by Assembly Bill (AB) 251, which was signed by the Governor in October 2023. To inform the work of the CTC, this report summarizes trends of road user injuries and fatalities in California and potential factors contributing to these trends (Chapter 2); summarizes trends in vehicle weight, size, and height for registered vehicles in California (Chapter 3); documents the landscape of policy solutions focused on vehicle size that might address California’s road user injuries and fatality challenge (Chapter 4); analyzes the impact of potential weight-based fees on consumer vehicle purchasing behavior (Chapter 5); and, analyzes the relationship between shifts in passenger vehicle weight and degradation of road infrastructure (Chapter 6).

In California, transportation plays a key role in community college access because many community college districts have satellite campuses, have limited transportation options, and tend to not have on-campus housing. To better understand the mobility challenges students face accessing community colleges and provide potential policy strategies to overcome these challenges, the researchers interviewed local transportation agencies, community college administrators, and students at five California community colleges between September 2022 and October 2023. Participants were asked about available transportation options for community college students, typical student travel patterns, and the resources needed to support improved community college transportation access. Small group discussions with students focused on student travel patterns, mobility challenges, and opinions on potential strategies to improve access. In addition, we reviewed state legislation on student transportation to understand current and past policy attempts to address community college transportation challenges. Together, the findings inform a set of policy options, such as student transit passes, public transit enhancements aimed at meeting the needs of students, and transportation pilot programs.

Recent studies suggest that there could be significant value to electric vehicle (EV) drivers and power companies from incorporating EVs into the state’s electrical power grids, known as Vehicle-Grid Integration (VGI). However, the benefits could be highly variable depending on the location of the utility territory, vehicle type and battery capacity, the relevant timeframe, and whether the connection involves only managed charging or includes bidirectional charging permitting vehicle to grid (V2G) power transfer, and other factors. Various studies conducted to date generally conclude that the opportunities for V2G could have two to three times the value of managed (or “smart”) charging. However, there are considerable additional complications for grid integration, including variable and site-specific implementation costs. Some savings such as deferring distribution system upgrades can be very significant but are also site-specific and depend on the level of curren and projected demands for electric power on the individual distribution feeder lines, and are therefore difficult to predict.

In this article we use four different indices to measure cost performance of the European Airline Industry. By using the number of routes as an indicator of Network Size, we are able to estimate indicators of Economies of Density, Network Size and Spatial Scope. By estimating total and variable cost functions we are also able to calculate an index of the excess capacity of the firms. For this purpose, we use data from the years 1984 to 1998, a period during which several deregulation measures were imposed on the European airline industry.    Some of the implications of this deregulation process for the cost performance of the industry are presented and discussed. Our results suggest that in the year 1998, almost all the firms had Economics of Density in their existing networks, while several of the firms also had  Economies of Network Size and Economies of Spatial Scope. All of the firms had excess capacity of fixed inputs. These results support our hypothesis that fusion, alliance, and merger strategies followed by the principal European airlines after 1998 are not just explained by marketing strategies, but also by the cost structure of the industry.

This report explores opportunities for employing autonomous driving technology to dampen stop-and-go waves on freeways. If successful, it could reduce fuel consumption and emissions. This technology was tested in an on-road experiment with 100 vehicles over one week. Public stakeholders were engaged to assess the planning effort and feasibility of taking the technology to the next level: a pilot involving 1000+ vehicles over several months. Considerations included the possible geographical boundaries, target fleets of vehicles, and suitable facilities such as bridges or managed lanes. Flow smoothing technology may improve the user experience and operations of managed lanes or bridges, however it may require external incentives such as reduced tolls to entice the traveling public to use it. This must be matched with other goals such as verifying vehicle occupancy. It might be possible for some hybrid solution that addresses both challenges to provide a way forward. A concept of operations needs to be developed specifically for a target road geometry and a California partner. This concept should benefit from lessons learned from previous pilot projects and will need to be defined so as to achieve both (1) a penetration rate sufficient to achieve measurable effects; and (2) sufficient quality and quantity of data to confirm benefits.

Advanced air mobility (AAM) is a broad concept that enables consumers access to air mobility, goods delivery, and emergency services through an integrated and connected multimodal transportation network. AAM can provide short-range urban, suburban, and rural flights of about 50-miles and mid-range regional flights up to a several hundred miles. State law delegates responsibility for oversight in aviation primarily to the California Department of Transportation (Caltrans). This white paper presents an overview of the state of the market, such as the aircraft under development and forecast market growth and discusses factors that could facilitate the development of AAM or pose risks to its deployment or to the public, including the safety and the regulatory environment, airspace and air traffic management, security, environmental impacts, weather, infrastructure and multimodal integration, workforce and economic development, social equity, and community engagement and social acceptance. It concludes by recommending actions that Caltrans and other state agencies can take to facilitate the development of AAM.

This paper develops models to quantify the dynamics of the impact of domestic air travel on the spread of the COVID-19 pandemic in the United States, using a wide range of datasets covering the period from March to December 2020 – when international travel was restricted and became a minor source of new COVID-19 cases across country borders. With the help of flight operation data, we first develop a novel approach to estimate the county-level daily air passenger traffic, which combines passenger load factor estimates and information about the air traffic distribution. Cross-sectional models using aggregated county-level variables are estimated. While this study focuses on air travel variables, we also control for potential spatial autocorrelation and other relevant covariates, including vehicle miles traveled (VMT), road network connectivity, demographic characteristics, and climate. The model results indicate that air travel has a strong and positive impact on the initial pandemic growth rate for both case-based and fatality-based aggregate models, but this impact attenuated after the first few months of the pandemic.

For evacuations, people must make the critical decision to evacuate or stay followed by a multi-dimensional choice composed of concurrent decisions of their departure time, transportation mode, route, destination, and shelter type. These choices have important impacts on transportation response and evacuation outcomes. While extensive research has been conducted on hurricane evacuation behavior, little is known about wildfire evacuation behavior. To address this critical research gap, particularly related to joint choice-making in wildfires, we surveyed individuals impacted by the 2017 December Southern California Wildfires (n = 226) and the 2018 Carr Wildfire (n = 284). Using these data, we contribute to the literature in two key ways. First, we develop two latent class choice models (LCCMs) to evaluate the factors that influence the decision to evacuate or stay/defend. We find an evacuation keen class and an evacuation reluctant class that are influenced differently by mandatory evacuation orders. This nuance is further supported by different membership of people to the classes based on demographics and risk perceptions. Second, we develop two portfolio choice models (PCMs), which jointly model choice dimensions to assess multi-dimensional evacuation choice. We find several similarities between wildfires including a joint preference for within-county and nighttime evacuations and a joint dislike for within-county and highway evacuations. Altogether, this paper provides evidence of heterogeneity in response to mandatory evacuation orders for wildfires, distinct membership of populations to different classes of people for evacuating or staying/defending, and clear correlation among key wildfire evacuation choices that necessitates joint modeling to holistically understanding wildfire evacuation behavior.