Household Income and Vehicle Fuel Economy in California

This white paper presents the findings from an analysis of the fiscal implications for vehicle owners of changing from the current statewide fuel tax to a “road user charge” (RUC) based on vehicle-miles traveled (VMT). Since 1923, California’s motor vehicle fuel tax has provided revenue used to plan, construct, and maintain the state’s publicly funded transportation systems. Over time, improvements in vehicle fuel efficiency and the effects of inflation have reduced both the revenue from the fuel tax and its purchasing power. Thus, there is growing interest among policy makers for replacing the state’s per-gallon fuel tax with an RUC based on VMT. This study analyzes the 2010-2011California Household Travel Survey (CHTS) to identify the potential effects this policy change would be likely to have on households across the state. The analysis found that while daily household fuel consumption and VMT both appear to increase with household income, urban and rural households show roughly the same amount of fuel consumption and VMT. No statistically significant difference in cost was found between the two programs in any income group. This suggests that an RUC designed to collect the same amount of revenues statewide as the current fuel tax would not place a significant financial burden on California households

Coupled opto-electronic simulation of organic bulk-heterojunction solar cells: parameter extraction and sensitivity analysis

A general problem arising in computer simulations is the number of material and device parameters, which have to be determined by dedicated experiments and simulation-based parameter extraction. In this study we analyze measurements of the short-circuit current dependence on the active layer thickness and current-voltage curves in poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) based solar cells. We have identified a set of parameter values including dissociation parameters that describe the experimental data. The overall agreement of our model with experiment is good, however a discrepancy in the thickness dependence of the current-voltage curve questions the influence of the electric field in the dissociation process. In addition transient simulations are analyzed which show that a measurement of the turn-off photocurrent can be useful for estimating charge carrier mobilities.Comment: 10 pages, 12 figures, 2 tables, Accepted for publication in Journal of Applied Physic

Design of Peptide Inhibitors That Bind the bZIP Domain of Epstein–Barr Virus Protein BZLF1

Designing proteins or peptides that bind native protein targets can aid the development of novel reagents and/or therapeutics. Rational design also tests our understanding of the principles underlying protein recognition. This article describes several strategies used to design peptides that bind to the basic region leucine zipper (bZIP) domain of the viral transcription factor BZLF1, which is encoded by the Epstein–Barr virus. BZLF1 regulates the transition of the Epstein–Barr virus from a latent state to a lytic state. It shares some properties in common with the more studied human bZIP transcription factors, but also includes novel structural elements that pose interesting challenges to inhibitor design. In designing peptides that bind to BZLF1 by forming a coiled-coil structure, we considered both affinity for BZLF1 and undesired self-association, which can weaken the effectiveness of an inhibitor. Several designed peptides exhibited different degrees of target-binding affinity and self-association. Rationally engineered molecules were more potent inhibitors of DNA binding than a control peptide corresponding to the native BZLF1 dimerization region itself. The most potent inhibitors included both positive and negative design elements and exploited interaction with the coiled-coil and basic DNA-binding regions of BZLF1.David H. Koch Institute for Integrative Cancer Research at MIT (Graduate Fellowship)National Institutes of Health (U.S.) (Award GM067681)National Science Foundation (U.S.) (Award 0821391

Metropolitan Transportation Commission Discretionary Transit Funding Methods Evaluation

In 2021, the Santa Clara Valley Transportation Authority (VTA) approached the Mineta Transportation Institute (MTI) with a proposal to have MTI provide an evaluation of the Metropolitan Transportation Commission’s (MTC’s) operational discretionary funding allocation policies and methods for Bay Area transit operators. The research was done in two parts. Part 1 investigated MTC’s past and current allocation methods for discretionary operational transit funding programs; Part 2 involved the evaluation of outcomes if MTC employed alternative allocation methods. After the Part 1 review of MTC’s various transit funding programs, the federal pandemic relief funds and the Transportation Development Act/State Transit Assistance (TDA/STA) funding programs were selected and evaluated in Part 2 using a set of five alternative allocation metrics and compared to actual MTC allocations. Key findings include: (1) the population-based metric produced the largest increase for VTA’s pandemic relief funds, with VTA receiving 221 percent more than MTC actually allocated in 2020 and 2021, but the San Francisco Municipal Transportation Agency (SFMTA) receiving 64 percent less; (2) the ridership-based metric yielded the smallest amount of VTA pandemic funding, but high ridership operators such as SFMTA would have a 41 percent increase; (3) the population-based metric produced the largest increase in STA funding to VTA but would come at the expense of other transit operators, with Sonoma County receiving 51 percent less; and (4) the ridership-based metric yielded the smallest amount of STA funds for VTA, with 50 percent less funding than actual, while high ridership operators such as SFMTA, would see a roughly 400 percent increase. Thoroughly investigating current and alternative funding allocation methods and policies is critical to understanding their effects on transit agencies and the communities they serve

Defining and Measuring Equity in Public Transportation

Transit should serve all users, regardless of age, race, ability, or any other identity. Policies and planning must be conscious of inequities when defining and measuring equity in public transportation. This study was done to aid the California Department of Transportation (Caltrans) and the state’s transit agencies in assessing transit service equity and assisting with evaluating past, existing, and future inequities. This report identifies and evaluates policies and practices associated with equity measurement in public transit from extant academic and professional literature sources. These include the Federal laws and regulations addressing Title VI of the 1964 Civil Rights Act and the measurement tools (i.e., metrics) that are used to identify and evaluate equity impacts related to transit benefits and costs. The report identifies a list of candidate metrics and applies them to a test case in Santa Cruz County, California, and compares their results to those generated by the metrics required by Title VI (race and income) for transit equity analysis. From this comparison, the study evaluated the need for new metrics in transit equity. Findings suggest that these traditional Title VI measures do not correlate well with other potential measures of inequity. Hence, transit inequity is a multifaceted problem with several potential different measures, each revealing an aspect of inequity. Caltrans and other transit-related agencies need to reach beyond these traditional measures, finding metrics that address the specific, context-appropriate equity conditions of the communities they are measuring to ensure fair and equal public transportation for all