Faculty Publications
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Item Factors Influencing Post-encroachment Time of Road Crossing Pedestrians Near Bus Stops Located on Mid-Block Sections(Springer Science and Business Media Deutschland GmbH, 2024) Ajaykrishnan, M.J.; Sethulakshmi, G.; Mohan, M.The increase in road traffic poses a significant threat to vulnerable road users, heightening the demand for their safety. According to the recent Road Accidents Statistics (MoRTH, 2020), out of the total road accidents reported in 2020, 15.8% involved pedestrians, and 65.1% occurred on straight road sections. This highlights the difficulty and lack of safety for pedestrians. Lack of visibility is the major cause of most accidents, and in the case of bus stops, parked buses affect the visibility of crossing pedestrians. In this study, traffic safety of crossing pedestrians is analysed using the proactive approach, which identifies an observable non-crash event that could have led to a conflict. Post-Encroachment Time (PET) is the most popular time-based measure that is the least time-consuming for accurate estimation of surrogate safety. This paper focuses on determining factors which affect PET of pedestrian crossings at mid-block sections with designated or undesignated bus stops. Videographic surveys were conducted at two mid-block sections with bus stops in Kerala, where accidents to pedestrians are frequent. Kinovea software was used to extract data from the recorded video samples, and IBM SPSS software was used to outline the factors influencing PET. The study found PET of crossing pedestrians to have a high positive correlation with the time taken for the vehicle to approach the crossing pedestrian, while other factors like evasive action and compliance behaviour were negatively correlated. The study proposed a model that will enable the easy computation of PET values of crossing pedestrians. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Investigating bus stops' influence on saturation flow at signalized intersections in heterogeneous traffic(Aracne Editrice, 2022) Shubhashree, K.S.; Mohan, M.The public transportation system efficiently reduces congestion and pollution as they lessen the dependency on personalized modes. However, most bus stops are located close to the intersection, and the stopping buses often create a bottleneck. At signalized intersections, this will seriously impact the saturation flow as it hinders the efficient functioning of the traffic signal system, resulting in delays and reduction of the intersection's capacity. Hence, a profound understanding of the factors associated with bus stoppages, which influence the saturation flow, is essential in designing efficient signalized intersections. This study simulates traffic flows at signalized intersections in heterogeneous traffic in a micro-simulation software VISSIM. Results of multiple simulation run indicated that saturation flow at intersections depends on the percentage of buses in the vehicular mix, the distance of bus stop from the stop line, and percentages of right and left-turning traffic. Further, the study proposes separate saturation flow models for upstream and downstream bus stop conditions. These could be used to optimally place bus stops near the intersection such that it does not hamper the performance of the intersection while not causing any undue discomfort to the bus passengers. © 2022, Aracne Editrice. All rights reserved.Item Application of Public Transit AVL Data for Evaluation of Delay Variability(Institute for Transport Studies in the European Economic Integration, 2023) Harsha, M.M.; Mulangi, R.H.; Panditharadhya, B.J.The travel time is the significant factor in evaluating efficiency and performance of public transit system. A greater percentage of travel time is accounted by bus stop delays which depends on passenger count, bus stop characteristics, traffic condition, bus performance, etc. Many of the Indian transit agencies store the passenger details stage wise not stop wise, which makes it difficult to evaluate delay variability at bus stop level. In this connection, Automatic Vehicle Location (AVL) data from Intelligent Transport System (ITS) implemented at Mysore, India is considered for evaluating bus stop delay variability. The collected data is used for estimating delay at five stops by adopting trajectory-based formulation. The probability distributions have been utilized to model the variability in delay. The performance has been analysed using Kolmogorov-Smirnov (KS) test. The daily variability of delay at bus stops has been evaluated using Coefficient of Variation (COV). The results of the performance evaluation of delay distributions show that the Generalized Extreme Value (GEV) distribution is the best descriptor of the delay variability in terms of accuracy, robustness, and survival capacity. In the absence of passenger data collection systems, method of evaluation of delay using AVL data presented in this study is helpful. © 2023 Institute for Transport Studies in the European Economic Integration. All rights reserved.Item Modelling personal safety perceptions at bus stop: employing hierarchical confirmatory factor analysis and structural equation approach(Aracne Editrice, 2023) Sethulakshm, G.; Mohan, M.Vehicle-pedestrian interactions occurring within a limited space are quite common at bus stops, making it essential to comprehend passengers' perception of safety near bus stops. Since the sense of perceived safety is subjective, developing a standardized tool to measure travellers' perception of safety, especially of bus users, is complex. The first part of this study aims to identify the indicators for measuring the perceived safety at bus stops, and the second part focuses on modelling the overall perceived safety of users’ at bus stops using structural equation modelling. The research examined the safety factors according to 14 indicators which were further reduced to five latent constructs using exploratory factor analysis. Perceived safety is taken as a second-order latent construct, and the second-order confirmatory factor analysis found that safety derived from five latent variables, namely bus stop facility, bus stop location, bus operator behaviour, other users' behaviour, and pedestrian facility, are potential indicators of overall perceived safety at the bus stop. The results recommend that providing night light facilities, adopting measures to avoid improper stopping of buses and left-side overtaking, avoiding bus stops on curves and junctions, and ensuring better sidewalk facilities could improve perceived safety. Structural equation modelling revealed that safety perceptions are negatively influenced by previous accident victimization and witnessing, age, educational qualification and total household vehicles. The results conclude that female respondents perceive less safety than males, and no effects can be attributed to the frequency of travel and trip length. The research findings will be helpful for the planning agencies to prioritize measures to improve travellers' feeling of safety. © 2023, Aracne Editrice. All rights reserved.Item Designing safe and accessible bus stops: an exploration of the interplay between perceived safety at crosswalk and transit ridership(Routledge, 2025) Sethulakshmi, G.; Mohan, M.Measuring personal safety perception is inherently complex, involving a multifaceted array of factors. This research advances the field of knowledge by developing a novel factor structure to assess pedestrian safety perceptions and modelling overall safety as a latent construct through a second-order Confirmatory Factor Analysis. Data were collected from 568 pedestrian interviews on safety perceptions near bus stops. The study concluded that perceived safety can be measured using four latent constructs: crosswalk infrastructure, crossing environment, management measures, and driver behavior, which collectively contribute to overall crosswalk safety. Using Structural Equation Modelling, the study confirms that as perceived safety while accessing bus stops via crosswalks decreases, bus ridership also declines. Findings also reveal demographic differences, with women, older individuals, and prior accident victims perceiving bus stop environments as less safe. Results suggest that policymakers should prioritize dedicated crosswalks and control speed and aggressive driving to maximize perceived safety at bus stops. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item Modelling sidewalk safety perceptions of pedestrians accessing bus stops and uncovering its role in shaping bus ridership: An empirical investigation(Elsevier Ltd, 2025) Sethulakshmi, G.; Mohan, M.Measuring personal safety perception is a complex task, as it encompasses a multi-faceted array of factors. This study explores the factors influencing the perceived safety of pedestrians while accessing bus stops via sidewalks and develops a comprehensive measurement model for sidewalk safety perception. Additionally, the study investigates potential links between sidewalk safety perceptions and bus ridership by applying Structural Equation Modelling (SEM). Data were collected from 568 personal interviews conducted across various Indian cities, focusing on pedestrians’ perceptions of safety while accessing bus stops. Perceived safety was conceptualized as a latent construct, with second-order confirmatory factor analysis identifying three primary dimensions: “Safety from Sidewalk Infrastructure”, “Safety from Other User Behavior” and “Safety from Sidewalk Maintenance and Management”. These three latent constructs collectively represent the overall safety perception of sidewalks in the context of bus stop access. Further analysis found that most bus users prefer a minimum sidewalk width of 1.5–2 m and an increased minimum width of 2–4 m near bus stops. The findings offer valuable insights into the intricate factors shaping pedestrian safety perceptions and provide a robust framework for enhancing sidewalk conditions to promote safer and more accessible public transit usage. © 2025 Elsevier Ltd