Development of Bus-Stop Time Models in Dense Urban Areas: A Case Study in Washington DC

Bus transit reliability depends on several factors including the route of travel, traffic conditions, time of day, and conditions at the bus stops along the route. The number of passengers alighting or boarding, fare payment method, dwell time (DT), and the location of the bus stop also affect the overall reliability of bus transit service. This study defines a new variable, Total Bus Stop Time (TBST) which includes DT and the time it takes a bus to safely maneuver into a bus stop and the re-entering the main traffic stream. It is thought that, if the TBST is minimized at bus stops, the overall reliability of bus transit along routes could be improved. This study focused on developing a TBST model for bus stops located near intersections and at mid-blocks using ordinary least squares method based on data collection at 60 bus stops, 30 of which were near intersections while the remaining were at mid-blocks in Washington DC. The field data collection was conducted during the morning, mid-day, and evening peak hours. The following variables were observed at each bus stop: bus stop type, number of passengers alighting or boarding, DT, TBST, number of lanes on approach to the bus stop, presence of parking, and bus pad length. The data was analyzed and all statistical inferences were conducted based on 95% confidence interval. The results show that the TBST could be used to aid in improving planning and scheduling of transit bus systems in an urban area

Identification of poor households for premium exemptions in Ghana’s National Health Insurance Scheme: empirical analysis of three strategies

OBJECTIVES: To evaluate the effectiveness of three alternative strategies to identify poor households: means testing (MT), proxy means testing (PMT) and participatory wealth ranking (PWR) in urban, rural and semi-urban settings in Ghana. The primary motivation was to inform implementation of the National Health Insurance policy of premium exemptions for the poorest households. METHODS: Survey of 145-147 households per setting to collect data on consumption expenditure to estimate MT measures and of household assets to estimate PMT measures. We organized focus group discussions to derive PWR measures. We compared errors of inclusion and exclusion of PMT and PWR relative to MT, the latter being considered the gold standard measure to identify poor households. RESULTS: Compared to MT, the errors of exclusion and inclusion of PMT ranged between 0.46-0.63 and 0.21-0.36, respectively, and of PWR between 0.03-0.73 and 0.17-0.60, respectively, depending on the setting. CONCLUSION: Proxy means testing and PWR have considerable errors of exclusion and inclusion in comparison with MT. PWR is a subjective measure of poverty and has appeal because it reflects community's perceptions on poverty. However, as its definition of the poor varies across settings, its acceptability as a uniform strategy to identify the poor in Ghana may be questionable. PMT and MT are potential strategies to identify the poor, and their relative societal attractiveness should be judged in a broader economic analysis. This study also holds relevance to other programmes that require identification of the poor in low-income countries

Effectiveness of community health financing in meeting the cost of illness.

How to finance and provide health care for the more than 1.3 billion rural poor and informal sector workers in low- and middle-income countries is one of the greatest challenges facing the international development community. This article presents the main findings from an extensive survey of the literature of community financing arrangements, and selected experiences from the Asia and Africa regions. Most community financing schemes have evolved in the context of severe economic constraints, political instability, and lack of good governance. Micro-level household data analysis indicates that community financing improves access by rural and informal sector workers to needed heath care and provides them with some financial protection against the cost of illness. Macro-level cross-country analysis gives empirical support to the hypothesis that risk-sharing in health financing matters in terms of its impact on both the level and distribution of health, financial fairness and responsiveness indicators. The background research done for this article points to five key policies available to governments to improve the effectiveness and sustainability of existing community financing schemes. This includes: (a) increased and well-targeted subsidies to pay for the premiums of low-income populations; (b) insurance to protect against expenditure fluctuations and re-insurance to enlarge the effective size of small risk pools; (c) effective prevention and case management techniques to limit expenditure fluctuations; (d) technical support to strengthen the management capacity of local schemes; and (e) establishment and strengthening of links with the formal financing and provider networks

Exploring Strategies to Improve Mobility and Safety on Roadway Segments in Urban Areas

Several strategies have been proposed and developed to alleviate the congestion and throughput problem usually experienced in urban areas. These strategies include the use of Intelligent Transportation Systems, signal re-timing and signal coordination, among others. In urban areas, there are often combinations of signalized and un-signalized intersections on corridors that may impact throughput and mobility. This research investigated driver compliance rate (CR) with STOP-signs at All-Way STOP Control (AWSC) intersections that are in close proximity to upstream or downstream signalized intersections. Also, strategies to improve mobility and throughput on segments in an urban area were explored via modeling and simulation. Thirty isolated segments with combinations of signalized and un-signalized intersections in the District of Columbia were selected for the study. Field data (traffic volumes, signal timing, lane configurations, etc.) were collected at each intersection of the segments. Driver compliance with STOP-signs at AWSC intersections within the segments was also observed. In all, 13,956 observations were made at 57 AWSC intersections. The segments were then modelled in the software program, and two scenarios were simulated. The “before” scenario simulated the existing conditions on the segments. In the “after” scenario, the AWSC intersections in each segment were signalized (and optimized), while maintaining the same conditions at the signalized intersections. Control delay and average travel speed were the measures of effectiveness (MOEs) that were used to assess the performance of the segments in both scenarios. The results of a regression analysis showed a positive relationship between CR and the distance between the existing AWSC and signalized intersections. A nonlinear regression model developed indicates that, to achieve a minimum compliance rate of 95%, a minimum distance of approximately 1,298 ft. between the intersections is required. Also, a test of comparison of means of the segments’ MOEs in the “before” and “after” scenarios showed significant improvements in the “after” scenarios. Statistically significant reductions in control delays on the segments were reported, while the average travel speed of vehicles significantly increased. The study revealed that even though some un-signalized intersections may not meet the MUTCD warrants for signalization, signalizing and coordinating them with existing signalized intersections will improve mobility and throughput

Inkjet-printed graphene electrodes for dye-sensitized solar cells

We present a stable inkjet printable graphene ink, formulated in isopropyl alcohol via liquid phase exfoliation of chemically pristine graphite with a polymer stabilizer. The rheology and low deposition temperature of the ink allow uniform printing. We use the graphene ink to fabricate counter electrodes (CE) for natural and ruthenium-based dye-sensitized solar cells (DSSCs). The repeatability of the printing process for the CEs is demonstrated through an array of inkjet-printed graphene electrodes, with ∼5% standard deviation in the sheet resistance. As photosensitizers, we investigate natural tropical dye extracts from Pennisetum glaucum, Hibiscus sabdariffa and Caesalpinia pulcherrima. Among the three natural dyes, we find extracts from C. pulcherrima exhibit the best performance, with ∼0.9% conversion efficiency using a printed graphene CE and a comparable ∼1.1% efficiency using a platinum (Pt) CE. When used with N719 dye, the inkjet-printed graphene CE shows a ∼3.0% conversion efficiency, compared to ∼4.4% obtained using Pt CEs. Our results show that inkjet printable graphene inks, without any chemical functionalization, offers a flexible and scalable fabrication route, with a material cost of only ∼2.7% of the equivalent solution processed Pt-based electrodes.Authors acknowledge support from CAPREX, Cambridge Africa Alborada Fund, Carnegie-University of Ghana Next Generation of Africa Academics programme and the Royal Academy of Engineering (RAEng) through a research fellowship (Graphlex)

Predicting Acceptable Wait Times for Patrons at Transit Bus Stops by Time of Day

The time spent waiting by bus patrons at bus stops is a primary measure for assessing the reliability of transit services. Uncertainty associated with waiting affects bus patrons’ perception of quality of the service provided. Consequently, this study aimed to determine patrons’ maximum and minimum acceptable wait times at bus stops in Washington, DC and to develop prediction models to provide decision-makers with additional tools for improving patronage. The data used in this study was obtained by surveying 3,388 bus patrons at 71 selected bus stops in Washington, D.C. over an eight-month period. Data obtained from patrons included their ethnicity, gender, minimum and maximum acceptable wait times (beyond the scheduled bus arrival time), alternate transportation mode choice, and knowledge of bus arrival times. Additionally, data on the operational characteristic of the buses were obtained via video playback of video recordings of cameras installed at the selected bus stops. In addition, information and conditions at each bus stop at the time of each survey was recorded. Statistical analyses were conducted to determine if there were any statistically significant differences in the maximum acceptable wait time of patrons based on gender and ethnicity. Further, models were developed to predict the maximum acceptable wait time of patrons. From the results, the mean of the reported maximum acceptable wait time was 8.5 minutes and 8 minutes, for female and male patrons, respectively. Also, the highest reported acceptable wait time beyond the scheduled bus arrival time was 20 minutes, while the mean differences between the maximum acceptable wait times of patrons grouped by ethnicity were determined to be statistically significant at a 5% significance level. Also, the results showed that White patrons had statistically significant lower maximum acceptable wait times than did patrons of other racial/ethnic groups

Teachers' selection and enactment of mathematical tasks for instruction in the classroom

Researchers have revealed that most of the hours spent in mathematics lessons are used for solving mathematical tasks. A mathematical task is defined as an individual problem or a set of related problems that direct students’ attention toward a particular mathematical thought. There have been significant changes in the mathematics school curriculum in many countries with Norway not being an exception. For example, fewer mathematical concepts are being taught deeply in Norway to stimulate conceptual understanding rather than just a shallow treatment of mathematical concepts. Also, the importance of teaching and learning approaches to motivating students to be active learners is emphasized in the curricula. The importance of students acting independently and taking responsibility for their learning is also highlighted. These changes have prompted the adoption of proper methods in the teaching and learning of mathematics, and the use of good mathematical tasks has been identified as one of the vehicles needed to drive these changes. This research aims to investigate how mathematical teachers select and enact mathematical tasks in their classrooms by looking at the sources of the tasks they use, the cognitive demand of the tasks, the factors they consider when they are choosing the tasks, modifications they make to the tasks, if any, and why they make modifications to the tasks, if any, and finally the interactions in the classrooms that may change the cognitive demand of the tasks. In this study, a total of twenty-three teachers from the southern part of Norway were selected to participate in the study with three participants selected to participate in the case study and twenty others in the survey. The sources of empirical data for the study were interviews, classroom observations, curriculum documents (for the case study), and survey questionnaires (for the survey). The findings of the study suggest that even though there is a plethora of resources/sources that the teachers get tasks from, the predominant of them is the textbook. Other major sources of tasks are mathematikk.no, and ndla.no, which are internet resources. Aside from the use of the resources as sources of tasks, other dominating uses of the resources include lesson planning and making instructional explanations. The findings indicate that most of the tasks used by the teachers are at the lower level of cognitively demanding tasks as per the task analysis guide of Stein and Smith (pg.16). The findings again show that the major factors that teachers consider when selecting tasks include tasks that stress on mathematical ideas, focuses on the students, and have applications to other topics. Furthermore, the findings iv revealed that even though the tasks selected by the teachers were lower-level tasks, however, the teachers did not modify the individual tasks to make them more challenging for the students. According to the teachers, the tasks were many and good, and served as a guide for the exams are some of the reasons why they did not modify the individual tasks. Moreover, the set of tasks was sometimes modified to reduce the time needed to complete them and make them suitable for the students. Lastly, the findings indicate that the instructional habits and dispositions of the teachers and the students in the classroom reduced the cognitive demands of the tasks. As a didactical implication, Teachers are advised to re-design or modify textbook tasks to offer the opportunity for students to develop deeper mathematical thinking. Furthermore, teachers must set goals they want to achieve with the tasks and stick with them. If the goal is for the students to work with the tasks at the highest level of difficulty, then they are advised to use indirect ways to participate in the students thinking rather than getting directly involved. Future research must explore the relationship between students and mathematical tasks. Keywords: mathematical tasks, mathematical task selection, tasks modifications, cognitive demand of mathematical task