Bus Transit Operational Efficiency Resulting from Passenger Boardings at Park-and-Ride Facilities

In order to save time and money by not driving to an ultimate destination, some urban commuters drive themselves a few miles to specially designated parking lots built for transit customers and located where trains or buses stop. The focus of this paper is the effect Park-and-Ride (P&R) lots have on the efficiency of bus transit as measured in five bus transit systems in the western U.S. This study describes a series of probes with models and data to find objective P&R influence measures that, when combined with other readily-available data, permit a quantitative assessment of the significance of P&R on transit efficiency. The authors developed and describe techniques that examine P&R as an influence on transit boardings at bus stops and on bus boardings along an entire route. The regression results reported are based on the two in-depth case studies for which sufficient data were obtained to examine (using econometric techniques) the effects of park-and-ride availability on bus transit productivity. Both Ordinary Least Square (OLS) regression and Poisson regression are employed. The results from the case studies suggest that availability of parking near bus stops is a stronger influence on transit ridership than residential housing near bus stops. Results also suggest that expanding parking facilities near suburban park-and-ride lots increases the productivity of bus operations as measured by ridership per service hour. The authors also illustrate that reasonable daily parking charges (compared to the cost of driving to much more expensive parking downtown) would provide sufficient capital to build and operate new P&R capacity without subsidy from other revenue sources

Steps to Supplement Park-and-Ride Public Transit Access with Ride-and-Ride Shuttles

Public transit ridership in California declined in the five years before the pandemic of 2020–21 and dropped significantly further after the pandemic began. A sharp downward step in the level of transit boarding occurred after February 2020, and continues to the date of this report as a result of the public-health guidance on social distancing, expanded work-at-home, and a travel mode shift from public transit to private cars. A critical issue has come to the foreground of public transportation policy, namely, how to increase the quality and geographic reach of transit service to better serve the essential trips of mobility disadvantaged citizens who do not have access to private vehicle travel. The research focus of this report is an examination of the circumstances where fixed route bus route service could cost-effectively be replaced by on-demand microtransit, with equivalent overall zone-level efficiency and a higher quality of complete trip service. Research methods were reviews of documented agency experience, execution of simple simulations, and sketch-level analysis of 2019 performance reported in the National Transit Database. Available evidence is encouraging and suggestive, but not conclusive. The research found that substitutions of flexible microtransit for fixed route buses are already being piloted across the U.S., with promising performance results. The findings imply that action steps could be taken in California to expand and refine an emphasis on general purpose microtransit in corridors and zones with a relatively high fraction of potential travelers who are mobility disadvantaged, and where traditional bus routes are capturing fewer than 15 boardings per vehicle hour. To be sufficiently productive as fixed route replacements, microtransit service technologies in the same or larger zones need to be capable of achieving vehicle boardings of five per hour, a challenge worth addressing with technology applications. Delivery of microtransit service can be undertaken through contracts with a growing set of private sector firms, which are developing processes to merge general purpose customers with those now assigned to ADA-required paratransit and Medi-Cal-supported non-emergency medical transport

Stability of elastically supported columns

A criterion is developed for the stiffness required of elastic lateral supports at the ends of a compression member to provide stability. A method based on this criterion is then developed for checking the stability of a continuous beam-column. A related method is also developed for checking the stability of a member of a pin-jointed truss against rotation in the plane of the truss

Sedimentary Mounds on Mars: Tracing Present-day Formation Processes into the Past

High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one and revealed spectacular views of finely layered sedimentary materials throughout the globe [1]. Some of these sedimentary deposits are 'mound' shaped and lie inside of craters (Fig 1). Crater mound deposits are found throughout the equatorial region, as well as ice-rich deposits found in craters in the north and south polar region [2-4]. Despite their wide geographical extent and varying volatile content, the 'mound' deposits have a large number of geomorphic and structural similarities that suggest they formed via equivalent processes. Thus, modern depositional processes of ice and dust can serve as an invaluable analog for interpreting the genesis of ancient sedimentary mound deposits

Assessment of biological role and insight into druggability of the Plasmodium falciparum protease plasmepsin V

Upon infecting a red blood cell (RBC), the malaria parasit

McLaughlin Crater as a Candidate Landing Site for Humans on Mars

McLaughlin Crater is an ancient (Noachian) Martian impact crater located at 337.6 East, 21.9 North, just south of the dichotomy boundary. This site should be considered for future landed exploration because: a) it is located at the boundary of three types of scientifically important terrain that will yield key results about the geological evolution and habitability of Mars; b) it contains surfaces where radiometric dating can be related to age dates estimated from crater counting, c) it contains volatile-rich rocks that will not only yield interesting results regarding ancient atmospheric chemistry, but will also be high quality, accessible targets for in-situ resource utilization (ISRU), and d) the site within the crater provides a flat, low-risk and low-elevation landing zone, which will facilitate landing large payloads on Mars

El programa Cyted: 10 Años de cooperación Iberoaméricana

El Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (CYTED) constituye un interesante ejemplo de continuidad y progreso en la cooperación iberoamericana. El CYTED tiene una serie de características que lo han convertido en un instrumento eficaz dentro del ámbito de la cooperación para el desarrollo, como es la cooperación científica y tecnológica, que requiere un alto grado de perseverancia, rigor y calidad

Geology of McLaughlin Crater, Mars: A Unique Lacustrine Setting with Implications for Astrobiology

McLaughlin crater is a 92-kmdiameter Martian impact crater that contained an ancient carbonate- and clay mineral-bearing lake in the Late Noachian. Detailed analysis of the geology within this crater reveals a complex history with important implications for astrobiology [1]. The basin contains evidence for, among other deposits, hydrothermally altered rocks, delta deposits, deep water (>400 m) sediments, and potentially turbidites. The geology of this basin stands in stark contrast to that of some ancient basins that contain evidence for transient aqueous processes and airfall sediments (e.g. Gale Crater [2-3])

Topological constraints in nucleic acid hybridization kinetics

A theoretical examination of kinetic mechanisms for forming knots and links in nucleic acid structures suggests that molecules involving base pairs between loops are likely to become topologically trapped in persistent frustrated states through the mechanism of ‘helix-driven wrapping’. Augmentation of the state space to include both secondary structure and topology in describing the free energy landscape illustrates the potential for topological effects to influence the kinetics and function of nucleic acid strands. An experimental study of metastable complementary ‘kissing hairpins’ demonstrates that the topological constraint of zero linking number between the loops effectively prevents conversion to the minimum free energy helical state. Introduction of short catalyst strands that break the topological constraint causes rapid conversion to full duplex

Developing Freight Analysis Zones at a State Level: A Cluster Analysis Approach

The ability to forecast freight to support transportation infrastructure decisions is limited by data availability at a level of detail meaningful to the transportation planner. The Freight Analysis Framework Version 2 is a national, comprehensive public freight database. The difficulty that transportation planners encounter when using this data is due to extensive aggregation. In this paper, the authors develop a methodology for creating freight analysis zones (FAZs) at a sub-state level by partitioning a state into meaningful zones that support freight transportation planning and analysis. The authors conc