published journal article
conference paper
published journal article
MS Thesis
working paper
This paper presents the preliminary findings from the Phase I evaluation of the Interstate 15 (I-15) Congestion Pricing Project in San Diego. It is a three-year demonstration that allows single occupant vehicles (SOVs) to use the existing 1-15 high occupancy vehicle (HOV) lanes for a fee. In Phase I, program participants were charged a monthly fee for unlimited use of the I-15 HOV lanes. The primary objectives of the project are: (1) to maximize use of the HOV lanes; (2) to test whether allowing solo drivers to use the HOV lanes’ excess capacity can help relieve congestion on the main lanes; (3) to improve air quality; and (4) to fund new transit and HOV improvements in the I-15 corridor. San Diego State University (SDSU) is conducting an independent, multi-element evaluation of the project to assess its impacts. The study will consider the project’s progress in meeting its primary objectives and provide detailed insight into the affect of congestion pricing on the I-15 corridor. The project has the potential to contribute to the broader understanding of many practical aspects associated with the implementation of congestion pricing in metropolitan areas. It also supplies data for the evaluation of benefits, which is central to the discussion of equity in the context of congestion pricing. This paper provides an overview of the project status and preliminary findings presented in detail in 22 Phase I technical reports that address a range of topics such as traffic, travel behavior, and institutional issues. The results from the first year of operations are limited, but indicate the project’s relative success. The project appears to be meeting its main objectives. In particular, the total number of vehicles using the HOV lanes increased substantially. The increase is attributed to increased number of carpools as well as project participants. The level of service (LOS) in the HOV lanes has not been adversely affected; LOS C was maintained throughout Phase I. In addition, there was a slight reduction of overall traffic volumes on the main lanes. Public acceptance of the project was evident in Phase I. The program participants viewed it as a success. However, understanding of the project’s overall objectives was low among both the program participants and the public. The majority of 1-15 users thought the ExpressPass program was fair to I-15 main lane and HOV lane users. Finally, there was evidence of sensitivity to price increases, although price levels during Phase I were not high enough to deter demand for the program.
research report
This study aimed to analyze LA Metro’s GoPass program, examining its usage patterns, participant characteristics, role in ridership recovery, and impact on students’ attendance. It also investigated free and discounted student transit pass programs across California and the influence of the COVID-19 pandemic. GoPass constituted 12.3% of LA Metro’s 2022 bus tap boardings, a significant portion amid a 33.4% overall ridership decrease compared to 2019. Spatial regression showed higher GoPass usage in areas with more young males and Asian residents, denser transit stops, mixed land use, and better transit access to participating schools. MUSD schools showed improved attendance in 2023 compared to 2022, particularly in intermediate schools. GoPass usage was highest among high schoolers, and increased use correlated with improved attendance, especially for minority and economically disadvantaged students, suggesting reduced absenteeism. Elementary and intermediate schools showed mixed attendance results. Our 2024 survey of transit agencies reveal that 38 agencies participating in both the 2019 and 2024 surveys expanded their student pass programs post-pandemic to boost ridership. LA Metro’s GoPass, a leading example adopted by agencies like Santa Monica, Long Beach Transit, and Gardena (GTrans), has a positive impact on ridership. Understanding the usage and characteristics of GoPass riders, both before and during the pandemic, is crucial for enhancing current fare-based incentive programs. These insights can also guide other transit agencies in developing similar initiatives to boost ridership and support students’ access to transportation.
published journal article
Preprint Journal Article
The Los Angeles County Metropolitan Transportation Authority (LA Metro) started in October 2021 the largest free transit pass program in the U.S. to date. Known as GoPass, it serves students from kindergarten to community colleges in Los Angeles County, the most populated county in the U.S. Although many free transit pass programs have been created, few have been analyzed from the point of view of transit agencies (i.e., for the characteristics of their users and their impact on ridership). To address this gap, the research first examines GoPass’ contribution to LA Metro’s bus boardings, before comparing selected characteristics of the students enrolled in GoPass in 2023 with census data. The research finds some opportunities for additional growth, including for female students. To understand GoPass usage, the research estimated a generalized spatial regression model that explains annual GoPass boardings aggregated by census tract (detailed usage data are unavailable to protect the students’ privacy) using a broad range of socioeconomic and built environment variables. The results confirm the presence of strong spatial effects. The research finds that census tracts with more young males, more transit stops, mixed land use, and more participating schools accessible within 30 min by transit have more GoPass boardings. Conversely, the number of GoPass boardings decreases with more access to private vehicles, property crimes, multifamily units, and a higher population density. A better understanding of the characteristics of GoPass users and GoPass usage is useful to improve GoPass and to inform transit agencies interested in creating similar programs.
published journal article
Skin diseases have become a global concern. This study aims to evaluate the associations between ambient air pollution and emergency room visits for skin diseases under the background of improving air quality in China. Based on 45,094 cases from a general hospital and fixed-site monitoring environmental data from 2014–2019 in Beijing, China, this study used generalized additive models with quasi-Poisson regression to estimate the exposure–health associations at lag 0–1 to lag 0–7. PM2.5 and NO2 exposure were associated with increased emergency room visits for total skin diseases (ICD10: L00-L99). Positive associations of PM2.5, PM10, O3 and NO2 with dermatitis/eczema (ICD-10: L20–30), as well as SO2 and NO2 with urticaria (ICD-10: L50) visits were also found. For instance, a 10 μg/m3 increase in PM2.5 was associated with increases of 0.7% (95%CI: 0.2%, 1.2%) in total skin diseases visits at lag 0–5 and 1.1% (95%CI: 0.6%, 1.7%) in dermatitis/eczema visits at lag 0–1, respectively. For PM2.5, PM10 and CO, stronger annual associations were typically observed in the high-pollution (2014) and low-pollution (2018/2019) years. For instance, a 10 μg/m3 increase in PM2.5 at lag 0–5 was associated with increases of 1.8% (95%CI: 1.0%, 2.6%) and 2.3% (95%CI: 0.4%, 4.3%) in total skin disease visits in 2014 and 2018, respectively. Our study emphasizes the necessity of controlling the potential health hazard of air pollutants on skin, although significant achievements in air quality control have been made in China.
working paper
Transit performance can be evaluated through quantitative indicators. As the provision of efficient and effective transit service are appropriate goals to be encouraged by federal and state governments, these goals are used to develop performance indicators. Three efficiency and four effectiveness indicators are described, together with two overall indicators. These nine indicators are analyzed for comparability utilizing operating and financial data collected from public transit agencies in California. Performance indicators selected for this study should not be viewed as final. Twenty-one performance indicators proposed by previous studies were reviewed. Theoretical considerations and unavailability or unreliability of data caused omission of several useful measures like passenger-miles. Circumstances such as improved data, emphasis upon goals other than efficiency and effectiveness, and local conditions might warrant the inclusion of indicators deleted from this research.
research report |
Dec 1977
published journal article |
Dec 1978