Exploring Bicycle and Public Transit Use by Low-Income Latino Immigrants: A Mixed-Methods Study in the San Francisco Bay Area

Latin American immigrants will continue to make up a large share of transit ridership, bicycling and walking in the United States for the foreseeable future, but there is relatively little research about them. This mixed-methods study compares the travel patterns of low-income immigrants living in the San Francisco Bay Area with that of other groups and investigates the barriers and constraints faced by low-income immigrants when taking transit and bicycling. Much of the previous work on immigrant travel has relied on national surveys and qualitative analysis, which underrepresent disadvantaged population groups and slower modes of travel, or are unable to speak to broader patterns in the population. We conducted interviews with 14 low-income immigrants and a paper-based intercept survey of 2,078 adults. Interviewees revealed five major barriers that made public transit use difficult for them, including safety, transit fare affordability, discrimination, system legibility, and reliability. Although crime was the most prominent issue in interviews, the survey results suggest transit cost is the most pressing concern for low-income immigrants. Low-income immigrants were less likely than those with higher-incomes to have access to a motor vehicle, and were less likely than higher-income immigrants or the U.S.-born of any income to have access to a bicycle or bus pass. Finally, although most barriers to public transit use were the same regardless of nativity or household income, low-income immigrants were much less willing to take public transit when they had the option to drive and less willing to bicycle for any purpose. The prevalence of concerns about transit affordability, crime, and reliability suggest transit agencies should consider income-based fare reductions, coordinated crime prevention with local law enforcement, and improved scheduling

Pedestrian and Bicycle Safety Research Brief

As cities around the country adopt initiatives like Vision Zero to eliminate traffic deaths and serious injuries, they are faced with the question of how effective different types of interventions are. For example, do protected bike lanes or painted sharrows reduce the risk of severe injury to cyclists? A group of researchers from the New York University School of Medicine examined this question by studying where cyclists admitted to the hospital crashed and how severe their injuries were. This research brief explores their findings.&nbsp

Giving undocumented immigrants access to driver’s licenses has transportation benefits for everyone.

Despite the need for access to a car in most US towns and cities, only sixteen states effectively allow undocumented immigrants to obtain a driver’s license. In new research, Jesus M. Barajas finds that when undocumented immigrants have access to driver’s licenses, there is no change in the number of miles they drive or trips they drive alone, but it does increase the number of carpool trips taken

Evaluating Transportation Equity Data Dashboards

The historical impacts of transportation planning and investment have left lasting scars on communities of color and low-income communities. This research evaluates online equity tools that exist as spatial dashboards —i.e., interactive maps in which the parameters of interaction are controlled. Twelve tools ranging from the national to the local level were identified and qualitatively assessed for their ability to address conditions related to transportation equity. The evaluation focused on how each tool defines disadvantaged communities, the outcomes they measure (benefits, burdens, or other), their ease of use, and their ability to guide decisions about equity. The findings show a diversity of methods and metrics in defining disadvantage, with most relying on composite demographic indexes and comparative population thresholds. Tools most commonly provided accessibility metrics to assess transportation benefits, while incorporating a range of environmental and health indicators as burden measures. A minority of tools had integrated features to support planning or project implementation. This study provides examples of promising practices in transportation equity support tools

Estratigrafía y Petrología de la Secuencia Volcánica de Puertecitos, Noreste de Baja California. Transición de un Arco Volcánico a Rift

En la Provincia Volcánica de Puertecitos (PVP), en el NE de Baja California, una sucesión de depósitos piroclásticos y lavas riolíticas de la etapa temprana del rift del Golfo de California (Mioceno Tardío-Plioceno) sobreyace en discordancia a rocas andesíticas atribuidas al arco volcanico del Mioceno (Tma). En la franja oriental de la PVP se han documentado dos períodos de actividad volcánica contemporáneos al desarrollo del rift: uno a fines del Mioceno Tardío (ca. 6 Ma) y otro en el Plioceno Temprano (ca. 3 Ma). El primero incluye una secuencia de ignimbritas (Tobas El Canelo, Tmec) de más de 300 m de espesor contenida entre dos períodos efusivos de domos riolíticos. Los cambios de espesor de estas ignimbritas (Tmec), indican que su fuente está localizada hacia el NW de la zona de estudio, mientras que las coladas riolíticas son locales y forman una serie de domos sobrepuestos orientados N-S, en la misma dirección del fallamiento. A fines del Plioceno Temprano un segundo período de actividad explosiva produjo una serie de flujos piroclásticos de composición riolítica y dacítica (Tpr). Este paquete incluye hacia la costa central más de 20 unidades de depósito, con un espesor superior a 200 m que disminuye hacia el W y NNE, sugieriendo que la fuente de Tpr se encontraba al E de la costa actual. Hacia el norte, algunas unidades de Tpr se hallan interestratificadas con depósitos marinas someros del Plioceno Temprano. Este período culminó con la erupción del Volcán Prieto (monogenético) y derrames fisurales de composición andesítica durante el Plioceno Tardío y Pleistoceno. Las andesitas asociadas al rift en los dos períodos de actividad volcánica son comparativamente de escaso volumen, y se caracterizan por el bajo contenido de K_2O y contenidos variables de TiO_2 y MgO con relación a las andesitas y basaltos asociados al arco volcánico del Mioceno. La característica común de las andesitas y las riolitas es la asociación clinopiroxeno-ortopiroxeno (y olivino en algunos casos), y bajo o nulo contenido de biotita, hornblenda, feldespato alcalino y cuarzo. Lo anterior sugiere una mezcla de magmas, uno máfico a alta temperatura y con posible afinidad toleítica, y otro más diferenciado y frio posiblemente formado por material de la corteza. La generación del magmatismo está asociado a la tectónica transtensional, que en el NE de la PVP se manifiesta con una extensión en dirección ESE a ENE durante el Mioceno Tardío - Plioceno

Design of an electroflotation system for the concentration and harvesting of freshwater microalgae

Microalgae are considered as one of the most promising alternatives for the integrated use of agro-industrial water residues and the production of metabolites of high industrial interest. This is due to algae can grow on wastewater which in turn can reduce the emission of nutrients to rivers and lakes. However, the greatest scientific-technological barrier is the concentration and separation of the biomass produced. There are several processes used at different levels (from laboratory to industrial scale) such as flocculation, centrifugation, flotation, etc. These can be very expensive or can (possibly) contaminate the biomass. Unlike the previous ones, electroflotation has been proposed as a cost-efficient method, nevertheless its final efficiency will depend heavily on the type of alga and culture medium. Taking into account the above, the present project aims to design an electroflotation system for the concentration and harvest of microalgae biomass. The effect of several factors (pH, time, voltage and distance between the electrodes) and for types of materials (Copper, Aluminium, Iron and Steel) on biomass recovery efficiency from a culture of Chlorella vulgaris UTEX 1803 was evaluated by the implementation of a Design of experiments (43 non-factorial design) using STATISTICA 7.0. Results show that, the materials with higher concentration efficiency were cooper and aluminium with 40 and 80% respectively, and the most relevant factors were distance between electrodes (1-2 cm), time (>20 min) and Voltage (>15V). In order to increase the efficiency of the overall process a new 43 experimental factorial design was proposed using as factors distance between electrodes, time, voltage and agitation. Results show that agitation positively affects the total efficiency until reaching a total concentration of the biomass (100%). It was found that a voltage close to 50V and a time greater than 25 min positively affect the final efficiency of the copper and aluminium electrodes, however aluminium has the highest efficiency (> 95%) compared to copper (<85%)