A GIS-based approach to evaluating environmental influences on active and public transport accessibility of university students

Many young adults are susceptible to obesity issues and the increased health risks associated with a lack of physical activity. Those who are prone to gaining weight include university students. An active transport system (walking and cycling), in combination with well-funded public transport, are essential components of a sustainable urban transport network, offering many benefits to the health of the individual, as well as the environment, economy, and society as a whole. The spatial association between active mobility (i.e. the physical activity of a human being for locomotion) of young adults and the environment, however, is poorly understood. This study presents a GIS-based model to determine association of various environmental (natural and built environment) factors with locational accessibility of active and public transport trips taken by university students. A GIS-based ensemble of Frequency Ratio (FR) and the Analytical Hierarchy Process (AHP) model was established. We analysed the characteristics of locations accessed by university students in relation to eight environmental factors including slope, elevation, land use, population density, travel time, building density, intersection density, and public transport service area. The model was applied to the Grenoble metropolitan region of France, an area well-known for policies which promote active transport. The results indicated that intersection density and land use are strongly associated with active and public transport accessibility, with weights of 0.17 and 0.16, respectively. The presence of infrastructure to support active travel, and regulation to limit vehicular speed, also improved accessibility. Approximately 50% of the area of the Grenoble metropolitan region was defined as accessible and suitable ('moderate' to 'very high' degree) for active mobility. The results of this study could allow city planners to monitor the existing status of active and public transport facilities, and identify areas that require additional work to improve accessibility

Pedestrian facilities and perceived pedestrian level of service (plos) : a case study of chittagong metropolitan area, Bangladesh

The promotion of active transport (a type of sustainable transportation) such as walking is a form of response against environmental pollution engendering from transport sector. Pedestrian level of service (PLOS) is a measurement tool to evaluate the degree of pedestrian accommodation on roadway to provide a comfortable and safe walking environment. The roadway characteristics-based model to measure PLOS has been widely applied since this approach is conceived as being transferable to different contexts. We present a comprehensive framework to measure the influence of pedestrian facilities on perceived PLOS qualitatively and quantitatively. We modeled triangular relationships among pedestrian facilities, perceived roadway conditions (accessibility, safety, comfort, and attractiveness), and perceived PLOS to identify pedestrian facilities, related to footpath, carriageway, and transit, influencing perceived PLOS. We developed these models for a case study of Chittagong Metropolitan Area in Bangladesh. Poor condition of pedestrian facilities in the region resulted in PLOS B as the highest tier of perceived PLOS. Findings of this study showed that accessibility and attractiveness influenced the perceived PLOS for footpath, carriageway, and transit, whereas safety is an important roadway condition for carriageway and transit facilities. We further measured the influence of 22 selected parameters of pedestrian facilities on roadway conditions and perceived PLOS. We concluded that achieving a better perceived PLOS is dependent on the availability, maintenance, and planning of different pedestrian facilities, as improper placement and poor condition of such facilities increased the probability that a lower level PLOS will be perceived

The use of watershed geomorphic data in flash flood susceptibility zoning : a case study of the Karnaphuli and Sangu river basins of Bangladesh

The occurrence of heavy rainfall in the south-eastern hilly region of Bangladesh makes this area highly susceptible to recurrent flash flooding. As the region is the commercial capital of Bangladesh, these flash floods pose a significant threat to the national economy. Predicting this type of flooding is a complex task which requires a detailed understanding of the river basin characteristics. This study evaluated the susceptibility of the region to flash floods emanating from within the Karnaphuli and Sangu river basins. Twenty-two morphometric parameters were used. The occurrence and impact of flash floods within these basins are mainly associated with the volume of runoff, runoff velocity, and the surface infiltration capacity of the various watersheds. Analysis showed that major parts of the basin were susceptible to flash flooding events of a ‘moderate’-to-‘very high’ level of severity. The degree of susceptibility of ten of the watersheds was rated as ‘high’, and one was ‘very high’. The flash flood susceptibility map drawn from the analysis was used at the sub-district level to identify populated areas at risk. More than 80% of the total area of the 16 sub-districts were determined to have a ‘high’-to-‘very-high’-level flood susceptibility. The analysis noted that around 3.4 million people reside in flash flood-prone areas, therefore indicating the potential for loss of life and property. The study identified significant flash flood potential zones within a region of national importance, and exposure of the population to these events. Detailed analysis and display of flash flood susceptibility data at the sub-district level can enable the relevant organizations to improve watershed management practices and, as a consequence, alleviate future flood risk

The use of watershed geomorphic data in flash flood susceptibility zoning: a case study of the Karnaphuli and Sangu river basins of Bangladesh

The occurrence of heavy rainfall in the south-eastern hilly region of Bangladesh makes this area highly susceptible to recurrent flash flooding. As the region is the commercial capital of Bangladesh, these flash floods pose a significant threat to the national economy. Predicting this type of flooding is a complex task which requires a detailed understanding of the river basin characteristics. This study evaluated the susceptibility of the region to flash floods emanating from within the Karnaphuli and Sangu river basins. Twenty-two morphometric parameters were used. The occurrence and impact of flash floods within these basins are mainly associated with the volume of runoff, runoff velocity, and the surface infiltration capacity of the various watersheds. Analysis showed that major parts of the basin were susceptible to flash flooding events of a ‘moderate’-to-‘very high’ level of severity. The degree of susceptibility of ten of the watersheds was rated as ‘high’, and one was ‘very high’. The flash flood susceptibility map drawn from the analysis was used at the sub-district level to identify populated areas at risk. More than 80% of the total area of the 16 sub-districts were determined to have a ‘high’-to-‘very-high’-level flood susceptibility. The analysis noted that around 3.4 million people reside in flash flood-prone areas, therefore indicating the potential for loss of life and property. The study identified significant flash flood potential zones within a region of national importance, and exposure of the population to these events. Detailed analysis and display of flash flood susceptibility data at the sub-district level can enable the relevant organizations to improve watershed management practices and, as a consequence, alleviate future flood risk

Spatiotemporal dynamics of NO2 concentration with linear mixed models : a Bangladesh case study

There is currently a limited understanding of how climatic and anthropogenic factors affect atmospheric NO2 concentration, and how these factors are associated with air pollution over space and time. Using high-resolution TROPOMI satellite data, this study estimates both the degree of association between climatic and anthropogenic factors, and the spatiotemporal variability of NO2 concentration over Bangladesh. Several linear mixed models were developed to isolate possible factors affecting the NO2 concentration values recorded between July 2018 and June 2019). This included monthly mean maximum temperature (MMAXT), rainfall, wind speed (WS), relative humidity (RH), enhanced vegetation index (EVI), population density, and distance from industrial activities. The study revealed that the very urbanized central region of Bangladesh experienced high NO2 concentrations, particularly from September through to March. Dynamic variables such as RH, MMAXT, RAIN, and WS can positively or negatively influence NO2 depending on the time of year. Areas with a high vegetation cover, a low population density, and located some distance from industrial areas tended to have low NO2 concentrations. This study concluded that policy measures such as transboundary air quality agreements, the introduction of a month-specific green tax, decentralization, industrial relocation, and increased urban tree plantation activities could all prove valuable in reducing NO2 pollution in Bangladesh

Assessing the performance of public transport services in a developing country : a case study using data envelopment analysis

The accurate evaluation of public transport (PT) services in developing countries is a challenging task due to a lack of reliable data and formal guidelines. The aim of this study was to develop a framework addressing these data limitations and quantify PT performance using output-oriented Data Envelopment Analysis (DEA). The local bus service operation of Chattogram City Corporation area of Bangladesh was used as a case study. A performance assessment inventory was developed identifying the major stakeholders related to local bus service operations. The relative efficiencies of different bus routes (from users' and operators' perspectives) were estimated using the DEA model, which incorporated data from a semi-structured questionnaire survey linked with the inventory. The PT authority also ranked all bus routes according to their degree of efficiency. Results indicated that relative efficiency scores in various routes varied according to the stakeholders' perspectives. A range of different parameters were considered when evaluating the performance of the service. The proposed inventory and framework would be useful for policymakers and urban planners in sequencing and prioritising different routes. This optimisation process would provide improved transport services to the general public

Does children's independent mobility matter? Insights into escorting practices in a developing country

Understanding children's mobility behaviour and parents escorting practices are important to developing a children-friendly society. But only a few studies concerning children’s mobility behaviour have focused on developing countries. In this study, we attempted to develop an econometric model to understand escorting practices in a developing country. A multinomial logit (MNL) model is developed using travel diary data of 398 elementary school-going children, inhabiting in Chattogram City Corporation (CCC) area of Bangladesh. We have considered different combinations of environmental (both school and neighbourhood environment), socio-cultural, household, and personal factors to explain children’s independent mobility behaviour for both school and discretionary trip purposes. The findings suggested that children’s individual (e.g. education level) and parents’ sociodemographic (e.g. income, access to cars, mother’s education level) facilities available at school, and built-environmental factors (e.g. commercial density, road density, land use mix and proximity to open spaces) are significantly associated with parent’s choice for chauffeuring their children in CCC area. Results will be useful to planners and policy makers for formulating effective measures to promote children’s independent mobility and will be a guideline for urban planners to include children’s mobility demand for the neighbourhood as well as city design