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Open Access Publications from the University of California

Connected automated vehicle impacts in Southern California part-I: Travel behavior and demand analysis

(2022)

Connected and automated vehicle (CAV) technologies attracted extensive attention in the past decade. As CAV brings convenience to travel, people's travel behaviors and patterns might change significantly. Existing models, however, cannot comprehensively evaluate the impacts on transportation systems. This study adopted an activity-based approach to evaluate the comprehensive CAV impacts on the transportation system in Southern California. A stated-preference survey was conducted, and captured people's behavior changes associated with CAV deployment. The model prediction demonstrated that the total trip number increased by 9%, with an 13% growth in total car-like mode travel distance. Among all trip purposes, work trips contributed to 49% of total trip number growth and 75% of the increased car-like mode travel distance. The advanced CAV technology alone wouldn’t directly benefit future transportation systems and it is still critical to have appropriate policy interventions in place.

Connected automated vehicle impacts in Southern California part-II: VMT, emissions, and equity

(2022)

Connected and automated vehicle (CAV) technologies are likely to have significant impacts on people's travel behaviors and the performance of transportation systems. This study investigates the impacts of CAVs from various aspects, including vehicle miles traveled (VMT), emissions, and transportation equity in Southern California. A comprehensive model is developed by incorporating the supply-side improvement of CAVs, a modified activity-based demand model supported by survey data, and a multi-class highway assignment model. The simulation results showed that VMT and emissions would increase by 10%, and CAVs could worsen travel equity across income groups. To reduce the negative impacts caused by CAVs, we proposed and evaluated a series of travel demand management policies. The results indicated that all policies help to reduce the VMT and emission growth, while their performances in enhancing travel equity vary across metrics including accessibility, travel frequency, and travel distance.

Cover page of Examination of Key Transportation Funding Programs in California and Their Context

Examination of Key Transportation Funding Programs in California and Their Context

(2021)

Examination of Key Transportation Funding Programs in California and Their Context assesses the congruence between funding programs and state goals for transportation. Particular attention is given to major funding sources, such the State Operation and Protection Program, and programs designed to promote key state goals, including the Affordable Housing and Sustainable Communities program, the Transit and Intercity Rail Capital Program, the Transformative Climate Communities program, and the Sustainable Transportation Planning Grant program.

Cover page of How does traffic, or the fear of it, affect housing affordability? Examining the effect of Traffic Impact Analysis on Housing Production and Affordability

How does traffic, or the fear of it, affect housing affordability? Examining the effect of Traffic Impact Analysis on Housing Production and Affordability

(2021)

Traffic impact analysis (TIA), which estimates the traffic impacts of proposed land development, tends to bias against higher density developments in urban areas where traffic is often congested and travel alternatives plentiful. This has important implications for housing supply and affordability, suburban sprawl, and private vehicle dependence. We examine the understudied implication of TIA on housing by drawing on empirical evidence from distinct bodies of research in the transportation and land use planning literatures to describe the mechanisms through which TIA may affect housing market conditions. We conclude that TIAs likely have negative effects on urban housing production and affordability.