Advancing Road User Charge (RUC) Models in California: Understanding Social Equity and Travel Behavior Impacts

California is currently exploring a mileage-based road user charge (RUC) program as an alternative to the existing gas tax. This research explores the potential social equity implications of this change through a literature review, expert interviews (N=21), general population survey (N = 3,489; final N = 3,061), and discrete choice model. The literature review and expert interviews reveal that populations that may face equity concerns include women, rural residents, un- and under-banked households, and low-income individuals. However, various strategies and program design considerations exist to attempt to address these equity concerns. The survey identified regional travel patterns across Northern, Central, and Southern California including in total vehicle miles traveled (VMT), VMT by population density, person miles traveled (PMT), trip purposes, and mode. Additionally, the survey showed travel behavior differences by age and household structure, income level, and across employment sectors. Emerging travel behavior trends include work from home rates that vary by geography, age, and employment sector and increasing delivery service use, particularly by higher-income households in select geographies. However, delivery services also may assist in addressing resource access (e.g., for zero-vehicle households). Vehicle ownership rates and the distribution of vehicle fuel type, fuel efficiency, and VMT/taxable fuel consumption also vary across geographic and demographic conditions. Less than half of the survey respondents understand how transportation is funded, roughly half factor in travel costs when making transportation decisions, and about 30% are comfortable with sharing location information to public and private entities. The discrete choice model showed a strong preference for personal auto use, drivers are generally insensitive to auto costs, mode choice decisions made by the highest income groups are insensitive to a RUC, and Californians are more likely to consider non-driving modes for social/recreational trips.