Assessing sidewalk and corridorwalkability in developing countries

Finding a simple and less expensive method to assess and improve sidewalk and corridor conditions in developing countries is essential in order to motivate more people to walk. This study aimed to design and test a method that uses direct observations of driver behavior and street measurements to assess sidewalk and corridor walkability in developing countries. The proposed method includes different walkability indicators related to sidewalk features, crossing facilities, sidewalk facilities, and driver behavior to provide one score that represents the walkability of a sidewalk and one that represents the walkability of a corridor. The method was tested on streets from 10 neighborhoods in the city of Doha, Qatar. The results indicated that the developed method was easy to use and could efficiently measure various indicators, illustrating that it can be used to evaluate corridors with different characteristics to identify and rank areas that require improvement. The study's findings will provide maintenance agencies, policymakers, and practitioners in developing countries with a simple, efficient, and cost-effective method to evaluate, plan, rank, and improve the walkability of sidewalks and corridors. - 2019 by the authors.Funding: This report was made possible by a UREP grant [UREP 15-085-3-020] from the Qatar National Research Fund (a member of The Qatar Foundation).Scopu

Drivers' perceptions of smartphone applications for real-time route planning and distracted driving prevention

Given the increasing importance and availability of traffic-related smartphone applications, understanding their potential use is vital, especially in developing countries. This research explores motorist perceptions of the installation and use of two smartphone applications - a distraction-prevention application and a real-time traffic information and navigation application - in Qatar, a rapidly developing country in the Arabian Gulf region. This study represents the first attempt to investigate the potential market for these types of applications in a region with a unique social and cultural environment. A questionnaire-based survey was conducted to examine the drivers' interest in using both applications, their willingness to buy the applications, and their data privacy concerns. The results indicated that the potential market for these types of smartphone applications in Qatar is high. The potential for the real-time route planning application was found to be much higher than that of the antidistraction application, especially among female drivers. A high percentage of the drivers, especially younger and local drivers, were less enthusiastic about installing and using the distracted driving prevention application. Most of the participants willing to use both smartphone applications did not have data privacy concerns, but in return for allowing the applications to access their data, they expected some reduction in travel time and a safer trip. These findings provide a direction for the development of future policies and smart solutions in this region.This publication wasmade possiblebya UREP Award [UREP 22-062-2-022] from the Qatar Research Fund (a member of Qatar Foundation).Scopu

Right Turn Split: A New Design To Alleviate Weaving On Arterial Streets

While weaving maneuvers occur on every type of roadway, most studies have focused on freeway maneuvers. Weaving occurring on non-freeway facilities, such as arterial streets, can cause significant operational problems. Arterial streets weaving typically occur when vehicles coming from a side street at an upstream intersection attempt to enter the main street from one side to reach access points on the opposite site at a downstream intersection by crossing one or more lanes. This dissertation investigates the type of problems occurring on arterial streets due to the weaving movements and recommends a new design to alleviate weaving on arterial streets. Firstly, the dissertation examined the different weaving movements occurring between two close-spaced intersections at two sites in Florida and explained the breakdown conditions caused by the weaving movements at the two sites. Secondly, the dissertation proposed a new design, Right Turn Split (RTS), to alleviate the delay caused by the weaving movements. The new design proposed separating the worst weaving movement entering the arterial from the other movements and providing a separate path for this movement. The new method is easy to implement and does not require much right of way. Thirdly, the dissertation compared two microscopic models, SimTraffic and VISSIM, to choose the most suitable model to be used to study the operational benefits of the RTS design. Based on the results of the comparison, it was decided to use SimTraffic for the analysis. Fourthly, the dissertation proposed a new calibration and validation procedure for microscopic simulation models. The procedure was applied on SimTraffic using the traffic data from the two studied sites. The proposed procedure appeared to be properly calibrating and validating the SimTraffic simulation model. Finally, the calibrated and validated model was used to study the operational benefits of the RTS design. Using a wide range of geometric and volume conditions, 729 before and after pairs were created to compare the delay of similar scenarios before and after applying the RTS design. The results were analyzed graphically and statistically. The findings of the analysis showed that the RTS design provided lower delay on the arterial street than the original conditions

Comparison of SimTraffic and VISSIM Microscopic Traffic Simulation Tools in Modeling Roundabouts

Abstract SimTraffic and VISSIM are two microscopic traffic simulation tools that are capable of modeling arterial roads with signalized intersections and roundabouts. This study compares the performance of the two simulation tools in modeling dual lane and triple lane roundabouts under different scenarios such as traffic volume, proportion of left turning movement, and proportion of trucks in the traffic flow. The two simulation tools did not show statistically significant difference in general. However; in the case of high traffic volumes, VISSIM showed higher average delays than those from SimTraffic compared to nearly identical results in the case of low traffic volumes

Seven naphtho-γ-pyrones from the marine-derived fungus Alternaria alternata: structure elucidation and biological properties

Eight bioactive pyrone derivatives were identified from the culture of Alternaria alternata strain D2006, isolated from the marine soft coral Denderonephthya hemprichi, which was selected as its profound antimicrobial activities. The compounds were assigned as pyrophen (1), rubrofusarin B (2), fonsecin (3), and fonsecin B (5) beside to the four dimeric naphtho-γ-pyrones; aurasperone A (6), aurasperone B (7), aurasperone C (8), and aurasperone F (9). Structures of the isolated compounds were identified on the basis of 1D and 2D NMR spectroscopy and mass (EI, ESI, HRESI) data, and by comparison with the literature. Configuration of the four dimeric naphtho-γ-pyrones 6-9 was analyzed by CD spectra, exhibiting an identical stereochemistry

Evaluating the Operational Impact of Left-Turn Exclusive Number of Lanes: A Case Study from Qatar

Left-turning movements can significantly reduce the overall capacity of signalized intersections due to the queueing built up. Intersections with heavy left-turning volumes tend to use multiple lanes to accommodate left-turn movements, such as double and triple left-turn lanes. This study compares the potential impact of different left-turn configurations for saturated/near saturated levels. A signalized intersection located in the city of Doha, Qatar, is selected to be examined and evaluated. A microscopic simulation approach is used to replicate the existing conditions before implementing different traffic demands, left-turn bay configurations, and traffic control parameters. The results suggest that signalized intersections, in general, and left-turn movements, in particular, benefit from multiple left-turn lanes. However, the anticipated operational benefits vary depending on several factors, such as the demand for left-turn movements and the length of the left-turn bay. The findings obtained from this study could be helpful for planners and decision-makers to decide the type of left-turn lane treatment needed to increase the capacity for different conditions. This work can be extended to mathematically quantify the expected operational improvements at signalized intersection

Biological indicators, genetic polymorphism and expression in Aspergillus flavus under copper mediated stress

AbstractFungi are considered model organisms for studying stress response and metal adaptation for both biotechnological and environmental purposes. In a previous study, copper was added in concentrations 1 and 10mM to Aspergillus flavus to induce laccase production for bioremediation, but using high concentrations of copper resulted in laccase inhibition despite the increase in bioremediation. In this study, the same copper sulfate was added and some oxidative biomarkers and antioxidative defense enzymes were assessed for stressed cultures of both copper and gamma radiation which was used as a positive stress inducer. The increase in copper concentrations resulted in an increase in superoxide dismutase enzyme activity, lipid peroxidation and protein carbonylation. On the other hand, catalase was inhibited by the addition of both copper concentrations, but exposure to gamma radiation resulted in an increased copper production. Glutathione peroxidase showed variation under stress, while both reduced glutathione and mycelial growth decreased in copper amended cultures. There was an increase in total endogenous carbohydrates. The main location of copper at the end of the incubation period seemed to reside in the cytosolic fraction of the fungus as detected by atomic absorption spectrometry. Genetic polymorphism was evident in the presence of copper as detected by RAPD-PCR. The expression of both laccase and superoxide dismutase suggest that each has a specific role in bioremediation, depending on the added copper concentration

Evaluation of New Simplified Dynamic Lane Merging Systems (SDLMS) for Short-Term Work Zone Lane Closure Configuration

To improve traffic safety and mobility in work zone areas, the Dynamic Lane Merge (DLM) systems, intelligent work zone traffic control systems, have been explored by several states of the U.S.A. The DLM can take two forms; dynamic early merge and dynamic late merge. The DLM systems were designed to advise drivers on definite merging locations. Up to date, there are no studies that contrast both merging schemes in the field under matching work zone settings. This study suggests two Simplified Dynamic Lane Merging Systems (SDLMS) (early merge and late merge) to supplement the current Florida Maintenance Of Traffic (MOT) plans for a three-to-two- work zone lane closure configuration. Data was collected in work zones on I-95, Florida for three different maintenance of traffic plan treatments. The first maintenance of traffic plan treatment was the standard MOT plan employed by FDOT. The second MOT was the early SDLMS and the third MOT was the late SDLMS. Results showed that dynamic early merging (early SDLMS) outperforms late SDLMS and the conventional Florida MOT plans under lower demand volumes. However, results also showed that late SDLMS outperforms early SDLMS and MAS under higher demand volumes

Mansouramycins E–G, Cytotoxic Isoquinolinequinones from Marine Streptomycetes

Chemical investigation of the ethyl acetate extract from the marine-derived Streptomyces sp. isolate B1848 resulted in three new isoquinolinequinone derivatives, the mansouramycins E–G (1a–3a), in addition to the previously reported mansouramycins A (5) and D (6). Their structures were elucidated by computer-assisted interpretation of 1D and 2D NMR spectra, high-resolution mass spectrometry, and by comparison with related compounds. Cytotoxicity profiling of the mansouramycins in a panel of up to 36 tumor cell lines indicated a significant cytotoxicity and good tumor selectivity for mansouramycin F (2a), while the activity profile of E (1a) was less attractive

An Artificial Intelligence Approach to Estimate Travel Time along Public Transportation Bus Lines

Public transportation sectors have played significant roles in accommodating passengers and commodities efficiently and effectively. The modes of public transportation often follow pre-defined operation schedules and routes. Therefore, planning these schedules and routes requires extensive efforts in analyzing the built environment and collecting demand data. Once a transit route is operational as an example, collecting and maintaining real-life information becomes an important task to evaluate service quality using different Key Performance Indicators (KPIs). One of these KPIs is transit travel time along the route. This paper aims to develop a transit travel time prediction model using an artificial intelligence approach. In this study, 12 public bus routes serving the Greater City of Doha were selected. While the ultimate goal is to predict transit travel time from the start to the end of the journeys collected over a period of one-year, routespecific inputs were used as inputs for this prediction. To develop a generalized model, the input variables for the transit route included the number and type of intersections, number of each type of turning movements and the built environment. An Artificial Neural Networks (ANN) model is used to process 78,004 valid datasets. The results indicate that the ANN model is capable of providing reliable and accurate transit travel time estimates, with a coefficient of determination (R2) of 0.95. Transportation planners and public transportation operators can use the developed model as a tool to estimate the transit travel time