Kayvan Aghabayk

• PhD (Transportation)
• University of Tehran

Cyclists are among the most vulnerable road users, increasingly subject to various sources of distraction, including the use of mobile phones and engagement in other tasks while navigating urban environments. Understanding and mitigating the impact of these distractions on cyclist safety is crucial. Despite the importance of this issue, the effect...

Fully automated vehicles (FAVs) are anticipated to enter the passenger vehicle market soon. Given the uncertainties surrounding user adoption of this emerging technology, research is needed to understand their user acceptance. While most studies on the acceptance of automated vehicles have been conducted in upper-middle-income or high-income develo...

Risky driving behaviors of young novice drivers and related crashes pose not only a threat to road safety but also a significant challenge to sustainable development. The high rate of traffic crashes involving young drivers leads to substantial losses in human capital, productivity, and labor, which are irreparable and place a strain on societal re...

While current research extensively delves into the importance of driving skills and attitudes concerning traffic safety, a conspicuous gap remains in substantiating a meaningful correlation between self-reported driving skills and attitudes toward traffic safety. This underscores the need for more in-depth investigation and empirical evidence to be...

Growing global research utilizes user acceptance models to investigate the public acceptance of automated vehicles (AVs). A growing body of literature suggests it is essential to recognize cultural differences that may influence people's decisions and the intention to use (AVs). While the influence of perceived safety on AVs adoption has been exami...

Pedestrian risky behaviors are one of the contributing factors to crashes involving pedestrians. Therefore, it is crucial to comprehend the mechanisms by which pedestrians interact with many influential components in the traffic environment. This study aimed to evaluate pedestrians’ red light running intentions and related factors under different t...

Distracted driving poses one of the most significant risks to road safety. The current study aims to provide a deeper understanding of the factors affecting the severity of distracted driving crashes in New York City and to explore the temporal stability in the effects of different variables on crash outcomes in 2016 to 2019 period by adopting a po...

Run Off Road (ROR) crashes are frequent and pose a significant risk of injury and fatality. Given the complexity of their mechanisms and the interaction of multiple factors, this study aims to comprehensively investigate the factors influencing the severity of ROR crashes, which have been understudied. Furthermore, addressing the current methodolog...

Chain reaction crashes (CRC) begin with a two-vehicle collision and rapidly intensify as more vehicles get directly involved. CRCs result in more extensive damage compared to two-vehicle crashes and understanding the progression of a two-vehicle collision into a CRC can unveil preventive strategies that have received less attention. In this study,...

School trips affect different aspects, such as air pollution and urban traffic, and of personal wellbeing, such as students’ physical and mental health. The increasing concern about environmental sustainability has prompted a reevaluation of daily activities, including school transportation. While different factors that affect students’ school trip...

Pile-up (PU) crashes, which involve multiple collisions between more than two vehicles within a brief timeframe, carry substantial consequences, including fatalities and significant damages. This study aims to investigate the real-time traffic, environmental, and crash characteristics and their interactions in terms of their contributions to severe...

This study aims to assess the public acceptance of Autonomous Modular Transit (AMT) and identify key factors influencing people’s intentions regarding the future use of AMT. While the integration of autonomy and modularity in transport systems has gained attention in recent years among researchers, the study of AMT acceptance is non-existent in the...

The movement of passengers is a crucial component of a multi-modal transportation system. Many evacuation incidents at train stations have been reported, which have resulted in injuries and fatalities during emergencies. Although there is a considerable number of review studies on passenger or pedestrian crowd modelling, there is a lack of studies...

Pedestrian safety is a critical issue in the United Kingdom (UK) as pedestrians are the most vulnerable road users. Despite numerous studies on pedestrian-vehicle crashes globally, limited research has been conducted to explore the factors contributing to such incidents in the UK, especially on rural roads. Therefore, this study aimed to investigat...

Fewer studies have investigated the factors affecting fully Automated Vehicles (AVs) acceptance and their association with demographics and travel behaviour in the Australian context. Evidence shows that public opinions and adoption towards AVs may vary by country. Therefore, this study aims to systematically explore the factors affecting public op...

There has been an increasing trend in using user acceptance models to explore the public acceptance of automated vehicles (AVs) in different countries. Most of the previous studies have analysed perceived usefulness, behavioural attitude, subjective norms as well as perceived ease of use, but other important factors, such as trust and data privacy,...

Due to a lack of physical protection and balance, motorcycle riders are one of the most vulnerable road users and are more likely to suffer severe injuries than motorists. Between 2009 and 2020, about 60% of motorcycle crashes occurred on nonintersection urban roadways in Victoria, Australia. While considerable research on intersections and their i...

Traffic crashes involving pedestrians have a high frequency in developing countries. Among road users, pedestrians are the most vulnerable, as their involvement in traffic crashes is usually followed by severe and fatal injuries. This study aims to identify pedestrian crash patterns and reveal the random parameters in the dataset. A three-year (201...

Fully automated vehicles (FAVs) are predicted to enter the passenger vehicle market in the near future. Being a new technology, there is significant uncertainty on adoption by users. There is a need for studies on the user acceptance of autonomous vehicles. This study aims to assess user acceptance of FAVs in a middle-income country, Iran, by adopt...

The design of safe and efficient pedestrian facilities necessitates the knowledge of complex human movements, such as intersecting pedestrian streams, under different conditions. This study aims to experimentally investigate the impact of intersecting angles on collective crowd dynamics under two different urgency levels. Data were collected from a...

Although the relationship between anger and personality characteristics in the literature is well-acknowledged for drivers, there is a lack of systematic investigation of pedestrians. The current study aimed to evaluate pedestrian anger expression (PAX) and its contributing factors, including demographics, travel habits, and the big five personalit...

Limited studies have investigated pedestrians’ exit choices in an emergency in multi-level commercial buildings. In particular, the comparison between exit choices before and after awareness of an incident location is non-existent in the literature. Likewise, the influence of individual attributes, such as the presence of a child or a companion, on...

Introduction: An important issue affecting the safety of riders is running a red light. Many factors can affect this risky behavior including demographic, safety, and meteorological factors. Method: Using two models, the Prototype Willingness Model (PWM) and the Theory of Planned Behavior (TPB), this study examines this behavior. In this study,...

In developing countries such as Iran, due to the inadequate infrastructure for rail and air transportation facilities, intercity buses are the most common type of transportation for long distances. Because of the long hours of driving, bus driving is considered a challenging job. Moreover, given the high capacity of these vehicles, a small error fr...

Background The study of user satisfaction with public transport services is of key interest for enhancing public transport ridership. However, the elevated risks of virus transmission on public transport associated with COVID-19 have resulted in a shift towards private vehicles. This issue is of concern to policymakers due to reduced levels of publ...

COVID-19 has been associated with a decline in public transport ridership in many cities. However, the impact of the pandemic on passenger perceptions of public transport, particularly loyalty, remain largely unexplored. Using a case study of Tehran’s bus system, this paper aims to assess the moderating effect of COVID-19 on passenger loyalty. A cr...

Several studies have focused on ergonomics of commercial and urban bus drivers; however, there exists a dearth of research on BRT drivers. This study was conducted to investigate the factors affecting the BRT drivers' mental health and satisfaction. The study was carried out on 171 BRT drivers in Tehran, Iran. The required data were collected throu...

This study aimed to evaluate the driving behavior of taxi drivers in Isfahan, Iran, and assess the probability of a driver being among the high-risk taxi drivers. To identify risky driving behaviors among taxi drivers, the Driver Behavior Questionnaire (DBQ) was used. By collecting data from 548 taxi drivers, exploratory factor analysis identified...

This study aims to develop a modified version of the existing driving behaviour questionnaire (DBQ) by including items related to driving behaviour under rainy conditions to evaluate driving behaviour changes and their implications. A survey of 680 drivers in Iran was conducted with the modified DBQ considering rainy conditions. Exploratory and con...

Introduction: The safety of pedestrians is a major concern in Victoria, Australia. Despite the considerable number of pedestrian fatalities and injuries in traffic crashes, a limited number of studies focused on pedestrian crash severity in Victoria. Methods: This study investigates and identifies the influential factors determining the severity...

Upon exiting buildings, theatres, and stadiums, which house a great number of people, egress points can act as bottlenecks, resulting in crowded exits and decreased flows. Most studies investigating flow have been conducted in either narrow bottlenecks (doors) or funnel shape bottlenecks, with the latter investigating bottlenecks placed in the midd...

The community, and especially the family, affects children’s traffic safety. Parents influence children’s current and future traffic behaviors. Numerous studies have demonstrated a relationship between parenting style and children’s behavioral problems such as antisocial behaviors and delinquency, so the modification of parenting styles could have...

Understanding changes in travel behavior during the spread of pandemic diseases such as COVID-19 is important to develop a resilient transportation system. Since one of the most important ways to prevent the spread of this virus is to keep a safe distance from other people (i.e. social distancing), it has implications for the operations of public t...

This paper evaluates a priori acceptance of shared dockless e-scooters in Iran using the extended Technology Acceptance Model (TAM). The proposed extended model includes subjective norms, hedonic motivation, and environmental awareness in the acceptance of e-scooters in addition to the original TAM constructs. Also, two open-ended questions were pr...

Introduction: In recent years, Australia is seeing an increase in the total number of cyclists. However, the rise of serious injuries and fatalities to cyclists has been a major concern. Understanding the factors affecting the fatalities and injuries of bicyclists in crashes with motor vehicles is important to develop effective policy measures aim...

Road freight transport and heavy vehicles play a significant role in transporting commodities and merchandise goods in Australia. According to the predictions, heavy vehicle traffic in Australia will increase by 50 per cent by 2030. The heavy vehicle traffic growth increases safety concerns since the probability of vehicle crashes increases by five...

Understanding the relationship between bus-pedestrian crash severity and factors contributing to such crashes is important. However, there exists a dearth of research on the factors affecting bus-pedestrian crash severity. This study aims to fulfil this gap by investigating the factors affecting the severity of pedestrian injuries. A data set of bu...

Developing countries have a high frequency of traffic incidents involving pedestrians. Given the vulnerability of pedestrians, many of these incidents result in serious or fatal injuries. The present study aimed to validate a pedestrian behavior questionnaire in Iran to investigate Persian pedestrian behaviors and to understand the relationship of...

Despite many studies on exploring the behaviors of pedestrians crossing the road, there is a need for comprehensive studies that identify the factors that may influence pedestrians crossing behavior at signalized and unsignalized intersections. This study aims to comprehensively examine the influence of gender, age group, group-crossing, technologi...

Taxi drivers face many problems every day including safety issues. The tendency to quickly transport passengers to their destinations for more income has resulted in dangerous driving behaviors leading to traffic violations. So, taxi drivers need appropriate support and training programs to improve safety and reduce the risk of crashes. Implementin...

Objective There has been extensive research into road user behavior, although how pedestrians express their anger has yet to be explored. This is important given the high vulnerability of pedestrians and the additional risks that angry people often undertake. The present study developed a tool to measure one’s tendency to engage in aggressive acts...

Pedestrian’s speed is an important parameter for modelling and simulating pedestrians’ crowd movement under normal and emergency conditions. Limited studies have examined the effect of the slope of walkways on pedestrian’s speed. This study investigates the pedestrian’s normal walking and jogging speed on inclined and level walkways. Specifically,...

Aggressive driving is a global road safety concern. However, little research has been conducted to understand the frequency of aggression nor what factors contribute to this. Moreover, in these researches, the effect of personality aspects on various driving anger expressions has not been investigated. The current study aims to investigate how driv...

Ensuring a high level of customer satisfaction with public transport is a key objective for transit agencies wishing to maintain and/or increase service uptake. Importance – Performance Analysis (IPA) can be used to identify gaps in the performance of public transport service attributes relative to their importance. However, this approach is often...

Introduction: Buses are different vehicles in terms of dimensions, maneuverability, and driver's vision. Although bus traveling is a safe mode to travel, the number of annual bus crashes cannot be neglected. Moreover, limited studies have been conducted on the bus involved in fatal crashes. Therefore, identification of the contributing factors in...

The performance of employees in a transport set is highly affected by their satisfaction and occupational problems. Underground metro drivers work in special conditions as compared with the drivers of suburban trains and urban tramways. Even though several studies have focused on the ergonomics of train drivers, there is a dearth of research on und...

Professional drivers play a key role in urban road network safety. It is therefore important to employ safer drivers, also find the problem, and train the existing ones. However, a direct driving test may not be very useful solely because of drivers’ consciousness. This study introduces a latent predictor to expect driving behaviors, by finding the...

Simple circular curves have been proposed by the road specifications to be implemented in horizontal alignment. In these curves, the centrifugal force is applied suddenly to the vehicles at the beginning of the curve and remains constant at its maximum value until the end of the curve. The current research intends to introduce a new curve for horiz...

While buses are a safe form of transport in developed countries, developing countries like Iran face significant safety concerns regarding buses. Nevertheless, few studies have examined the factors associated with the number and severity of bus crashes. The present study investigates the underlying risk factors associated with the severity of urban...

Complex pedestrian or passenger crowd movements, such as intersecting movements, can create a bottleneck resulting in delays during emergency escape from public infrastructure such as major public transport hubs. Limited studies have examined the effect of different intersecting angles and walking speeds on pedestrian outflow. This study aims to sy...

Introduction: Motorcyclists are exposed to more fatalities and severe injuries per mile of travel as compared to other vehicle drivers. Moreover, crashes that take place at intersections are more likely to result in serious or fatal injuries as compared to those that occur at non-intersections. Therefore, the purpose of this study is to evaluate t...

Highways and in particular their pavements are the fundamental components of the road network. They require continuous maintenance since they deteriorate due to changing traffic and environmental conditions. Monitoring methods and efficient pavement management systems are needed for optimizing maintenance operations. Pavement performance prediction...

Understanding the impact of geometrical characteristics of bottlenecks in pedestrian egress behaviour is ubiquitous in safe and effective crowd management. This paper studies how funnel-shaped bottlenecks with different angles affect the microscopic and macroscopic properties of pedestrian egress flow. The minimum width of the bottleneck in all exp...

This study contributes towards enhancing two dimensions of traffic micro-simulation models. Firstly, it provides a methodology to reduce the calibration time and efort of micro-simulation models by integrating knowledge of multi-threading techniques and evolutionary algorithms. Secondly, it implements this methodology to calibrate a trafic micro-si...

Heavy vehicles influence general traffic in many different ways compared with passenger vehicles, and this may result in different levels of traffic instability. Increases in the number and proportion of heavy vehicles in the traffic stream will therefore result in different traffic flow conditions. This research initially outlines the different ca...

Many forms of complex pedestrian crowd behaviors, including merging, can be identified in built environments such as public transport stations and public buildings. Understanding and capturing this phenomenon in a robust model is a challenging task; it is also a significant opportunity for research, given the international demand for models of this...

Car-following (CF) models are fundamental in the replication of traffic flow and thus they have received considerable attention. This attention needs to be reflected upon at particular points in time. CF models are in a continuous state of improvement due to their significant role in traffic micro-simulations, intelligent transportation systems and...

Different behaviors of pedestrian under complex situations such as turning and crossing have been investigated in the past. However, few studies considered the behaviors of pedestrians in merging areas despite the fact that this situation is very common in built environment such as exit points of railway stations and stadium. Notwithstanding of the...

There are few studies investigating crowd dynamics in panic situations. They used measures such as exit flow rate to explore the exit performance in evacuation scenarios. However, there is limited research exploring the relationship of exit flow rate and density behind the exit for panic scenarios. This study presents a macro level analysis to inve...

Detailed understanding of the factors based on which individual pedestrians select an exit in a confined area, is of crucial importance in modelling crowd movement. Lack of explanatory disaggregate data representing the relative importance of the latent factors contributing to exit decision, continues to be obstacle to tackle the problem. The full...

SUMMARY This study develops a car-following model in which heavy vehicle behaviour is predicted separately from passenger car. Heavy vehicles have different characteristics and manoeuvrability compared with passenger cars. These differences could create problems in freeway operations and safety under congested traffic conditions (level of service E...

This paper uses a real-world data set to investigate a driver's car-following behaviour of different class of vehicles in congested traffic conditions. The existing car-following models do not explicitly consider heavy vehicle (HV) interactions with the other vehicles. This could become problematic in future due to the increasing proportion of HVs...

Heavy vehicles are significantly longer and heavier than passenger cars and consequently have quite different acceleration and braking capabilities. Heavy vehicle manoeuvres are therefore likely to influence drivers' vehicle-following behaviour differently to cars. Heavy vehicles can also influence the behaviour of drivers of other vehicles while f...

Following behaviour of passenger car drivers has been modelled in many studies over the last half a century. However, the existence of heavy vehicles in the traffic stream has not received the same level of attention. Heavy vehicles drivers show different following behaviour which could be the result of the different characteristics of their vehicl...

In the past decade, the development and the application of traffic microsimulation to replicate real-world traffic behavior have become pervasive among traffic and transport researchers. The modeling of a driver's car-following behavior, which forms the fundamental component of traffic microsimulation, has meanwhile been an important research direc...

Because car‐following (CF) models are fundamental to replicating traffic flow they have received considerable attention over the last 50 years. They are in a continuous state of improvement due to their significant role in traffic microsimulations, intelligent transportation systems, and safety engineering models. This article uses the local linear...

This study investigates the lane-changing behaviour of drivers of passenger cars and heavy vehicles on freeways and arterial roads. Lane changing has a significant influence on traffic flow through its impact on the surrounding drivers. In this study, detailed vehicle trajectory data are used as a basis for the analysis of drivers' behaviour. It is...

Traffic micro-simulation models have become very popular in transport studies and are extensively used in research and by industry. Traffic simulation models are especially very useful in reflecting the dynamic nature of transportation system in a stochastic manner, which is beyond the capability of some classic methods. Nevertheless, one of the ma...

Heavy vehicles and passenger cars differ in their maneuverability and acceleration capabilities. Heavy vehicles thus influence other traffic in a different manner than passenger vehicles, causing different levels of traffic instability. Increasing number and proportion of heavy vehicles in the traffic stream may result in quite different traffic fl...

The behavior of drivers of heavy vehicles when making a decision or executing a lane-changing maneuver on arterial roads and freeways is investigated. Vehicle lane-changing maneuvers often result in instability in traffic flow. The impact on traffic flow of lane changes by heavy vehicles can be even more serious than that of lane changes by passeng...