University of California Institute of Transportation Studies

Traffic signals, while serving an important function to coordinate vehicle movements through intersections, also cause frequent stops and delays, particularly when they are not properly timed. Such stops and delays contribute to significant amount of fuel consumption and greenhouse gas emissions. The recent development of connected and automated vehicle (CAV) technology provides new opportunities to enable better control of vehicles and intersections, that in turn reduces fuel consumption and emissions. In this paper, we propose platoon-trajectory-optimization (PTO) to minimize the total fuel consumption of a CAV platoon through a signalized intersection. In this approach, all CAVs in one platoon are considered as a whole, that is, all other CAVs follow the trajectory of the leading one with a time delay and minimum safety gap, which is enabled by vehicle to vehicle communication. Moreover, the leading CAV in the platoon learns of the signal timing plan just after it enters the approach segment through vehicle to infrastructure communication. We compare our PTO control with the other two controls, in which the leading vehicle adopts the optimal trajectory (LTO) or drive with maximum speed (AT), respectively, and the other vehicles follow the leading vehicle with a simplified Gipps’ car-following model. Furthermore, we extend the controls into multiple platoons by considering the interactions between the two platoons. The numerical results demonstrate that PTO has better performance than LTO and AT, particularly when CAVs have enough space and travel time to smooth their trajectories. The reduction of travel time and fuel consumption can be as high as 40% and 30% on average, respectively, in the studied cases, which shows the great potential of CAV technology in reducing congestion and negative environmental impact of automobile transportation.

Little is known about demand for EVs in the mass market. In this paper, we exploit a natural experiment that provides variation in large EV subsidies targeted at low- and middle-income households in California. Using transaction-level data, we estimate two important policy parameters using triple differences: the subsidy elasticity of demand for EVs and the rate of subsidy pass-through. Estimates show that demand for EVs amongst low- and middle-income households is price-elastic and pass-through is complete. We use these estimates to calculate the expected subsidy bill required for California to reach its goal of 1.5 million EVsby 2025.

This research presents a risk-informed framework to derive metrics characterizing and tracking the safety performance of heavy-duty automated vehicles (HD-AVs) operations. A combination of traditional and novel hazard identification methods are leveraged to study potential human-system interactions in HD-AVs operations, ranging from safety drivers to remote operators.

COVID-19 altered travel patterns in the U.S. Studies have analyzed the effect of the pandemic on travel mode, including working from home, but few have focused on automobile ownership—a relationship with potentially long-term consequences for accessibility, household budgets and debt, and policy efforts to meet climate goals.To understand the association between the pandemic and automobile ownership, we rely on a unique credit panel dataset from Experian and examine three different automobile loan-related outcome measures: annualized growth rate of new automobile loan balances, average new loan size, and the number of new loans. We focus specifically on changes across loans in neighborhoods by race/ethnicity, hypothesizing larger increases in automobile debt in Black and Latino/a neighborhoods, where workers are less likely to be able to telework. The annualized growth rate of new automobile loans increased during the pandemic across all neighborhoods by race/ethnicity, increasing most rapidly in Latino/a neighborhoods. Controlling for other factors, loan size increased similarly across neighborhoods by race/ethnicity. The increase in automobile lending in Latino/a neighborhoods, therefore, likely was explained by a significant uptick in the number of new loans.The growth in automobile lending during the pandemic was potentially prompted by pandemic-induced changes in the need for automobiles and facilitated by an expanded social safety net. As the pandemic and its various forms of public financial assistance recede, the findings underscore the importance of ongoing assistance in enabling automobile ownership or shared access among households with limited means whose livelihoods depend on the access that vehicles provide.

Most net-zero emissions targets require electrification of the entire light-duty vehicle fleet, and before that the electrification of all new vehicle sales. In this paper, we review literature on demand-side issues related to achieving 100% zero-emissions vehicle sales, focusing on plug-in electric vehicles (PEVs). We discuss potential demand-side challenges to increasing PEV sales and related research gaps, including consumer factors (perceptions, knowledge, and consumer characterises), demand-focused policy (incentives), infrastructure, and energy prices. While global PEV sales have substantially increased in recent years, several challenges remain: some demographic groups are currently underrepresented among PEV buyers (e.g. renters, lower income buyers), some car drivers are resistant to PEVs, incentives are influential but have predominantly benefited higher-income new-car buyers and are being phased out, infrastructure is not sufficiently developed or equally distributed, infrastructure is not user friendly, and some households lack charging access. Some issues we identify may be related to the early stage of the PEV market, though will need to be addressed to reach higher PEV sales and PEV fleet shares. Finally, we outline areas where more research is needed to understand and guide the PEV transition.

Connected and automated vehicles (CAV) have the potential to confer large benefits to California in economic development (job creation) and in improving the operation of its road transportation network. CAV systems are likely to become one of the most important application domains for modern information technology, employing large numbers of highly skilled people in research, development and implementation wherever the companies that are developing these systems find the local environment most hospitable. The CAV systems are expected to produce significant improvements in roadway capacity, traffic flow smoothness, driving comfort and convenience, energy efficiency, pollution reduction and traffic safety.

Federal and state governments are offering incentives to those who purchase or lease plug-in electric vehicles (PEVs), which include both battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs). Policymakers are beginning to consider the phase-out of these incentives and how a phase-out might impact PEV market growth. This brief highlights new research on the importance of incentives to consumers over time, based on survey data from 14,000 PEV-owning households in California between2010 and 2017, collected and analyzed by the Plug-in Hybrid & Electric Vehicle Research Center at UC Davis. The PEV incentives included as part of this research are those currently available to Californian consumers: high occupancy vehicle (HOV) lane access; the US federal tax credit, which offers up to $7,500 to PEV buyers; and the California Clean Vehicle Rebate Project (CVRP), which offers $1,500 for a PHEV, $2,500 for a BEV, and an additional $2,000 for low-income consumers

During the 2010s, public transit ridership declined significantly across the U.S., including in California. Over the same period, though, transit funding steadily increased each year. These two trends created challenging conditions for transit operators, which were losing riders despite expanding service. Then, the COVID-19 pandemic pushed transit ridership to historic lows. Though some riders have returned, transit’s ridership recovery has been highly uneven.UCLA researchers examined where, how, and why transit ridership and operations have changed during the pandemic by analyzing National Transit Database data, reviewing relevant academic literature, and conducting interviews with transit managers. While both the demand for and supply of transit have changed throughout the pandemic, long-established strategies for better service and increasing ridership still stand: improving reliability, frequency, and safety for users.

At present day, there are little to no policies around the use and implementation of micro-mobility in many cities. At the national level, there are no specific guidelines that outline how micro-mobility parameters should be implemented in a city. The National Transportation Board has left it up to metropolitan districts to decide on how to gauge the decision to install micro-mobility systems in their cities. However, best practice guidelines have been identified by the National Association of City Transportation Officials (NACTO) and the U.S. Department of Transportation Federal HighwayAdministration (FHWA).The U.S. Department of Transportation Federal Highway Administration (FHWA) provides a Shared Mobility Primer as a practical guide for local governments and public agencies as they seek to implement emerging services or manage existing shared services. The FHWA suggests to public agencies that the government should be consulted in the process of integrating shared mobility. The government should play a role in considering health, safety, consumer protection, taxation, insurance, parking and rights of way, signage and advertising, multimodal integration, planning processes, data sharing, data privacy and standards, and accessibility (Shared Mobility Current Practices and Guiding Principles, n.d.).

Many U.S. states are supporting the transition of the heavy-duty vehicle (HDV) sector to zero-emission vehicles (ZEVs), with California leading the way through its policy and regulatory initiatives. Within various HDV fleet segments, California’s drayage fleets face stringent targets, requiring all vehicles newly registered in the Truck Regulation Upload, Compliance, and Reporting System to be ZEVs starting January 2024, and all drayage trucks in operation to be zero-emission by 2035. Understanding fleet operator behavior and perspectives is crucial for achieving these goals; however, it remains a critical knowledge gap. This study investigates the preferences and influencing factors for ZEVs among drayage fleet operators in California. We conducted a stated preference choice experiment survey, developed based on previous qualitative studies and literature reviews. With participation from 71 fleets of various sizes and alternative fuel adoption status, we collected 648 choice observations in a dual response design, consisting of a forced choice between ZEVs and a free choice between ZEVs and status quo alternatives. Multinomial logit model analyses revealed driving range and purchase costs as significant factors for ZEV adoption, with charging facility construction costs also critical in hypothetical choices between ZEVs and status quo alternatives. Fleet or organization size also influenced ZEV choices, with large fleets more sensitive to operating costs and small organizations more sensitive to off-site stations. These findings enhance our understanding in this area and provide valuable insights for policymakers dedicated to facilitating the transition of the HDV sector to zero-emission.

Throughout the ongoing COVID-19 pandemic, changes in daily activity-travel routines and time-use behavior, including the widespread adoption of telecommuting, have been manifold. This study considers how telecommuters have responded to the changes in activity-travel scheduling and time allocation. In particular, we consider how workers utilized time during the pandemic by comparing workers who telecommuted with workers who continued to commute. Commuters were segmented into those who worked in telecommutable jobs (potential telecommuters) and those who did not (commuters). Our empirical analysis suggested that telecommuters exhibited distinct activity participation and time use patterns from the commuter groups. It also supported the basic hypothesis that telecommuters were more engaged with in-home versus out-of-home activity compared to potential telecommuters and commuters. In terms of activity time-use, telecommuters spent less time on work activity but more time on caring for household members, household chores, eating, socializing and recreation activities than their counterparts. During weekdays, a majority of telecommuters did not travel and in general this group made fewer trips per day compared to the other two groups. Compared to telecommuters, potential telecommuters made more trips on both weekdays and weekends while non-telecommutable workers made more trips only on weekdays. The findings of this study provide initial insights on time-use and the associated activity-travel behavior of both telecommuter and commuter groups during the pandemic.