Buildings are one of the biggest consumers of fossil fuels, and thus, contribute largely to greenhouse gas emissions. As a result, a large number of studies have been conducted and innovative ideas or green solutions have been invented, adopted, and implemented across the globe. These solutions are often contextual and heavily dependent on local environmental and socio-economic factors. Green roofs are such an example. Green roofs (both intensive and extensive) for buildings have been successfully adopted in many countries around the world. Bangladesh, a developing country that can benefit from green roofs, seems to remain in complete darkness regarding its potential. The objective of this study is to identify the reasons why green roofs have not been widely implemented in Bangladesh, especially in the capital Dhaka, even though, theoretically, the climatic conditions of this country favor this technology. This study focuses on the perception of the construction industry to comprehend the possible obstacles they are facing towards using green roofs in their designs. A questionnaire study was conducted among architects, engineers, construction managers, contractors, and owners who are at different levels of experience in their respective fields. The results indicate a gap in knowledge and misconceptions, which are major hindrances to the implementation of green roofs.

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Massive amount of plastic and polymer products are being produced worldwide on a daily basis. Most of these are intended to be recycled, but the reality is quite different. Statistics show that the percentage of recyclable plastic and polymer products that are actually recycled is very insignificant. These plastic products are mostly non-biodegradable. As a result, they persist in the environment as potential pollutants. Hence there have been countless attempts to reuse these plastic products through versatile applications. This paper attempts to compile the studies which explored the reusability of plastic products in structural concrete. The principal focus will be on use of recycled Polyethylene Terephthalate (PET) in structural concrete in various forms. This study concludes that incorporating PET as a supplementary material in different forms has both beneficial and harmful impacts on various fresh and hardened properties of concretes and thus should be considered for comprehensive investigation.

The length of an acceleration lane is one of the dominant freeway geometric design parameters. This length requires new analyses to anticipate the needs of heavy commercial vehicle (HCV) platooning. We evaluated the safety and operational impact of HCV platooning on acceleration lane length for a freeway ramp in Ontario, Canada. This study modified the 2018 AASHTO’s acceleration lane length estimation analytical model. Furthermore, this study used a VISSIM micro-simulation model and surrogated safety assessment model (SSAM) to examine the safety and operational impact on the real-world circumstances of HCV platooning at 0.6 s and 1.2 s headways and different market penetration rates of 0%, 5%, and 10%. The results suggest a minimum acceleration lane length of 600 m for platooned HCVs, which is inadequate compared to American and Canadian design guidelines. An extended acceleration lane length (600 m) will improve safety by reducing conflict by 19.2% and operational performance by reducing 3.9% of 85th percentile merging time for the operation of 5% HCV platooning with 0.6 s headway compared with 350 m acceleration lane length. This study suggests 5% of traffic containing two HCV platoons with 0.6 s headway may be reasonable for operation during certain hours of the day under existing conditions.

In the New Normal era of “Living with COVID-19”, we need a measure of the safety of street spaces. Social distancing during a pandemic is considered an effective safety measure, but the current binary threshold approach to social distancing is clearly inadequate for evaluating and monitoring the risk of infection on urban streets. This study is to propose a social distancing indicator that can quantitatively evaluate the level of exposure to viral infection for pedestrians using urban streets during a pandemic, and to develop a statistical model to estimate the proposed indicator from simulations of pedestrian activity on urban streets. We assumed that the risk of infection on urban streets has a direct relationship with distance between pedestrians. The social distancing indicator was based largely on the findings of past studies. We developed a statistical model to relate the proposed indicator to three other explanatory variables: pedestrian density, clumpiness, and directional heterogeneity. We used pedestrian simulation to generate the raw data for these explanatory variables. The social distancing indicator demonstrated a statistically significant relationship with input variables and can be used to evaluate pedestrians’ social distancing on urban streets. We measured the relationship between different levels of pedestrian density, clumpiness, and directional heterogeneity and related the results to the potential level of exposure to viral infection. Health agencies can use the findings to develop appropriate policies for monitoring and improving the social distance between pedestrians on urban streets during a pandemic.

This study investigated the operational impact of heavy commercial vehicle (HCV) platooning on urban arterials. HCV platooning is an important application of vehicle-to-vehicle (V2V) technology, with urban arterials facilitating an essential component of HCV movements when picking up and delivering goods. HCV platooning has the potential to reduce fuel consumption and emissions. Moreover, the increasing HCV driver shortage problem can be alleviated if the vehicle following behind a lead vehicle can function without a driver by using autonomous technology enabling Society of Automotive Engineers Level 4 or higher. PTV VISSIM was used to develop a set of micro-simulation models that investigated the impact of traffic signal priority (TSP) and low levels (0%, 5%, and 10%) of HCV platooning. The performance measures include travel time and the number of stops. With the existing traffic control system, HCV platooning increased travel time and increased the number of stops for all vehicles including passenger cars and HCVs. TSP with 5% HCV platooning improved travel time and decreased the number of stops for all vehicles. TSP with 10% HCV platooning, however, only decreased travel time and the number of stops for passenger vehicles. The results suggest that a higher penetration rate of HCV platooning may create significant delays and overwhelm the traffic system even with the assistance of TSP. The findings of this study highlight the potential for TSP to mitigate the impact of HCV platooning on traffic congestion. However, the TSP system may not be a panacea that works for all traffic compositions.

The safety of pedestrians, such as workers who largely walk to and from work, has not been given sufficient attention, especially in the area of traffic safety in developing countries, including Bangladesh. Although the National Road Safety Strategy has a very strong emphasis on road safety education and publicity campaigns, the road safety knowledge may not have reached these vulnerable road users who most needed them. Moreover, little is known about the penetration rate of these campaigns and who have benefited or not benefited from them. On the other hand, the developing country, like Bangladesh, is heavily dependent on its Readymade Garment (RMG) workers for earning foreign currency, and walking is one of the major mode of transports of those workers. The objective of this study is to identify those who are not reach by the safety education. Results from a survey of 1020 RMG workers around Dhaka identified several socioeconomic, demographic, travel characteristics and accident experience that affect the most vulnerable segments who are left out of the system. The findings of this study would help the policy makers to arrange necessary road safety education for the most vulnerable cohorts of pedestrians to encourage the continued use of this sustainable mode of commute.