Papers by Mahdi Aghaabbasi
Sustainability
Bike-sharing is known as a sustainable form of transportation. This travel mode is able to tackle... more Bike-sharing is known as a sustainable form of transportation. This travel mode is able to tackle the “last mile” transit issue and deliver financial, well-being, and low-carbon lifestyle advantages to users. To date, many studies have analysed the influence of various factors, including built environments, on bike-sharing ridership. However, no study has exclusively synthesised these findings regarding the association between built-environment attributes and bike-sharing ridership. Thus, in this study, a systematic literature review was conducted on 39 eligible studies. These studies were assessed with respect to (1) bike-sharing usage, (2) studies’ geographical distribution, (3) data collection and analysis method, and (4) built environment factor type. Most studies were carried out in the US and Chinese cities. Variables associated with diversity, density, and distance to public transport stations and public transport infrastructure were frequently employed by the studies reviewe...
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Sustainability, Mar 28, 2022
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Sustainability, 2022
In the United States, several studies have looked at the association between automobile ownership... more In the United States, several studies have looked at the association between automobile ownership and sociodemographic factors and built environment qualities, but few have looked at household travel characteristics. Their interactions and nonlinear linkages are frequently overlooked in existing studies. Utilizing the 2017 US National Household Travel Survey, the authors employed an extreme gradient boosting tree model to evaluate the nonlinear and interaction impacts of household travel characteristics and built environment factors on vehicle ownership in three states of the United States (California, Missouri, and Kansas) that are different in population size. To develop these models, three main XGBT parameters, including the number of trees, maximal depth, and minimum rows, were optimized using a grid search technique. In California, the predictability of vehicle ownership was driven by household travel characteristics (cumulative importance: 0.62). Predictions for vehicle owners...
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Sustainability, 2022
More than 8000 pedestrians were killed due to road crashes in Australia over the last 30 years. P... more More than 8000 pedestrians were killed due to road crashes in Australia over the last 30 years. Pedestrians are assumed to be the most vulnerable users of roads. This susceptibility of pedestrians to road crashes conflicts with sustainable transportation objectives. It is critical to know the causes of pedestrian injuries in order to enhance the safety of these vulnerable road users. To achieve this, traditional statistical models are used frequently. However, they have been criticized for their inflexibility in handling outliers and missing or noisy data, and their strict pre-assumptions. This study applied an advanced machine learning algorithm, a Bayesian neural network, which has the characters of both Bayesian theory and neural networks. Several structures of this model were built, and the best structure was selected, which included three hidden neuron layers—sixteen hidden nodes in the first layer and eight hidden nodes in the second and third layers. The performance of this m...
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Journal of Transport & Health, 2017
To date, several assessment tools have been developed to evaluate the pedestrian environments and... more To date, several assessment tools have been developed to evaluate the pedestrian environments and sidewalks at the street and neighbourhood level. While the existing tools that assess sidewalks at the street level consider the microscale sidewalk factors, the assessment tools at the neighbourhood level neglected the importance of microlevel factors for the assessment purpose. In addition, the important role of residents in neighbourhoods in the examination and review procedure of neighbourhood facilities is overlooked. In contrast with previous assessment methods that considered macro and mesoscale factors for assessment purpose, this research has developed an assessment method to evaluate the neighbourhood sidewalks using the microscale factors. This tool has been developed in the form of a questionnaire to assess the sidewalk conditions within the neighbourhoods. The proposed tool has been tested in three neighbourhoods within Johor Bahru District in Malaysia. Most sidewalk factors in these surveys showed moderate to high reliability. The results of using the proposed tool indicate that the tool is capable of identifying the drawbacks of neighbourhood sidewalks. In addition, this tool allows the residents to convey their needs to city planners and ask for improving existing sidewalks. Lastly, the tool appears ready to be used by urban planners and researchers.
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International Encyclopedia of Transportation, 2021
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Applied Sciences
The investigation of travel mode choice is an essential task in transport planning and policymaki... more The investigation of travel mode choice is an essential task in transport planning and policymaking for predicting travel demands. Typically, mode choice datasets are imbalanced and learning from such datasets is challenging. This study deals with imbalanced mode choice data by developing an algorithm (SVMAK) based on a support vector machine model and the theory of adjusting kernel scaling. The kernel function’s choice was evaluated by applying the likelihood-ratio chi-square and weighting measures. The empirical assessment was performed on the 2017 National Household Travel Survey–California dataset. The performance of the SVMAK model was compared with several other models, including neural networks, XGBoost, Bayesian Network, standard support vector machine model, and some SVM-based models that were previously developed to handle the imbalanced datasets. The SVMAK model outperformed these models, and in some cases improved the accuracy of the minority class classification. For th...
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Civil and Sustainable Urban Engineering
Now more than ever, the health and economic benefits of active transportation (AT) are evident an... more Now more than ever, the health and economic benefits of active transportation (AT) are evident and several planning efforts and programs are particularly targeted at improving active transportation options for different populations, such as students and seniors. Administrative employees at universities received less attention in the literature than other population groups.This population spends a lot of time doing sedentary activities and behaviors during their working time. Thus, the present study used a C5 decision tree to examine the usage of university employees’ AT modes when they are out of campus to get to work, shopping, and leisure. The effects of the sociodemographic and living environment of employees on their AT mode choice were also examined. According to the results, walking was the most frequently used mode to get to work and leisure and public transport was the most frequently used mode to get to shopping. Transit station conditions (25), sidewalk availability and co...
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International Encyclopedia of Transportation
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Sustainability
Walking is a sustainable commute mode, and walkability is considered an essential sign of sustain... more Walking is a sustainable commute mode, and walkability is considered an essential sign of sustainable mobility. To date, many walkability assessment tools have been developed to assess the walkability conditions across the world. However, there is a paucity of comprehensive methods to assess current walkability tools based on walking needs and ensure all walking requirements are included. Thus, researchers and experts are unable to select the most comprehensive tool systematically. The present study attempts to develop a system to evaluate the quality of the existing tools. The instrument focuses on factors related to walking needs frequently observed in all types of walkability assessment tools. Hence, a pilot measurement quality appraisal instrument (MQAI) is developed and tested by a research team with planning and public health backgrounds. The final MQAI is tested by suitable reliability, criterion, and content validity tests. Most appraisal scales display moderate to high reli...
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Cities
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Transportation Research Part A: Policy and Practice
Abstract This study used a survey technique to investigate factors that motivate the adoption and... more Abstract This study used a survey technique to investigate factors that motivate the adoption and the usage frequency of ride-sourcing among students in a Malaysia public university. Two of the most broadly used machine learning techniques, Random Forest technique and Bayesian network analysis were applied in this study. Random Forest was employed to establish the relationship between ride-sourcing usage frequency and students' socio-demographic related factors, built environment considerations, and attitudes towards ride-sourcing specific factors. Random Forest identified 10 most important factors influencing university students’ use of ride-sourcing for different travel purposes, including study-related, shopping, and leisure travel. These important predictors were found to be indicators of the target variables (i.e., ride-sourcing usage frequency) in Bayesian network analysis. Bayesian network analysis identified the students' age (0.15), safety perception (0.32), and neighbourhood facilities in a walkable distance (0.21) as the most important predictors of the use of ride-sourcing among students to get to school, shopping, and leisure, respectively.
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Measurement
Abstract Different assessment tools and questionnaires have been developed to measure happiness. ... more Abstract Different assessment tools and questionnaires have been developed to measure happiness. The Oxford Happiness Questionnaire (OHQ), that has 29 items, has been used widely to estimate personal happiness. The OHQ is used to quantify personal happiness based on an equal effectiveness assumption for all 29 items. Although the OHQ has been used by several studies, very few studies assess the contribution of the individual OHQ items in explaining personal happiness. The current study attempts to fill this gap by assessing the contribution of the individual OHQ items in explaining personal happiness as a latent variable. Structural Equation Modeling (SEM) is used to assess the relationship of the individual OHQ items in explaining personal happiness in Skudai, Johor, Malaysia. The significant OHQ items that are extracted from SEM results, are used to develop a new personal happiness measurement score. The SEM factor loading values are used to weight the extracted items. All usual clustering methods are used in this study and the most suitable one based on the higher silhouette value is chosen to cluster the proposed personal happiness index. Finally, the relationships between socio demographic factors and the proposed personal happiness index clusters are tested by Gamm and Pearson Chi-Square tests. The SEM results show that 16 out of the 29 OHQ items have poor associations with personal happiness and can be excluded from the model. Most of the non-significant items (items with low level of association) are negatively worded items and the majority of the significant items are related to personal attitudes. The proposed personal happiness index can help to save time and avoid confusion.
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Sustainable Cities and Society
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Sustainable Cities and Society
Abstract Even though assessing sidewalks is an integral component of walkability assessment tools... more Abstract Even though assessing sidewalks is an integral component of walkability assessment tools, no single study exists that adequately covers the relevance of existing walkability audits for sidewalk assessment. In this paper, an in-depth review of walkability audit tools is conducted. The primary objective of this study is to determine whether the existing tools consider factors such as safety, attractiveness, disability issues and path conditions that are essential for sidewalk assessment. This review shows that a limited number of audit tools consider disability issues, safety, and attractiveness. The tools reviewed mainly use path condition factors. In conclusion, recommendations are made for future walkability audits that focus on accessibility factors, as well as micro-scale design factors.
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Cities
Abstract Equitable use (EU) is the first principle of universal design and promotes the usefulnes... more Abstract Equitable use (EU) is the first principle of universal design and promotes the usefulness and marketability of products for people with diverse abilities. Sidewalks, as the main circulation path for pedestrian transportation, can be designed and assessed based on this principle to improve their usability for all pedestrians. Currently, there is no clear definition of EU in the sidewalk design criteria; consequently, no design and assessment guidelines are based on this concept. This study aims to remedy this shortcoming in knowledge by defining and translating the theoretical and conceptual components of the characteristics of EU for sidewalks. This study also attempts to identify the contributions of sidewalk design factors in the main dimensions of EU applied to sidewalks. To achieve these objectives, we conduct an extensive literature review of available universal design guidelines and handbooks as well as scientific articles regarding the implementation of EU in outdoor environments and sidewalks. The results of this review contribute to the development of conceptual models to define EU in sidewalk design. A questionnaire was administered to collect data to test the fitness of these conceptual models. Fitness tests are conducted with structural equation modelling (SEM). The EU translation can be useful for designing and assessing sidewalks to ensure that sidewalks serve people with various abilities on an equal basis.
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Journal of Transport Geography
Abstract Numerous techniques for collecting data are available to assess pedestrian built environ... more Abstract Numerous techniques for collecting data are available to assess pedestrian built environment features. Recently, several studies favoured Google tools over conventional data collection techniques because they are more cost- and time-effective. The use of Google tools to assess pedestrian built environments remains in its early stages. Various challenges are encountered in assessing certain types of features and the intervals between the time of image/video capture and assessment. Thus, an in-depth study on the challenges of employing the Google tools is necessary. This study discusses the issues associated with the use of Google tools to assess pedestrian built environments and attempts to introduce new objectives for further tools and studies in this field to eliminate the aforementioned shortcomings of the existing tools.
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Sustainability
This present study developed two predictive and associative Bayesian network models to forecast t... more This present study developed two predictive and associative Bayesian network models to forecast the tolerable travel time of university students to campus. This study considered the built environment experiences of university students during their early life-course as the main predictors of this study. The Bayesian network models were hybridized with the Pearson chi-square test to select the most relevant variables to predict the tolerable travel time. Two predictive models were developed. The first model was applied only to the variables of the built environment, while the second model was applied to all variables that were identified using the Pearson chi-square tests. The results showed that most students were inclined to choose the tolerable travel time of 0–20 min. Among the built environment predictors, the availability of residential buildings in the neighborhood in the age periods of 14–18 was the most important. Taking all the variables into account, distance from students’...
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In disasters, all sectors must be prepared to face any events. Transportation is the most importa... more In disasters, all sectors must be prepared to face any events. Transportation is the most important phase of an emergency plan that needs special attention. It is necessary to examine the transport infrastructures, personnel and vehicles to determine the preparedness of the transport phase. In this article, we propose a primary assessment framework to evaluate the elements involved in transport. The results of this assessment help decision makers to be more aware of the weaknesses and strengths of their system.
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Despite the vast studies on Katrina’s failures, little is known about the failures of bus deploym... more Despite the vast studies on Katrina’s failures, little is known about the failures of bus deployment through New Orleans’ pre-evacuation during Katrina. The final image that emerges from the literature is negative: unsuccessful and poor bus management before and through Katrina, the flooded buses in parking lots, and local authorities forgot the non-drivers. The objective of this study is to survey of previous approaches of bus deployment to support the emergency transportation operation. Canada, Cuba, and USSR were studied due to their success in deployment of buses through disasters. Discussion of the findings yields suggestions in three main fields: Management of assets (buses), emergency transportation plan, and identification of vulnerable residents and their preparedness to face traumatic events. This study attempts to increase the efficiency of bus deployment through the catastrophic events in disaster prone areas.
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Papers by Mahdi Aghaabbasi