Bus Drivers’ Perspectives on Factors Contributing to Road Traffic RTAs on Prithvi and Mugling-Narayanghat Highway Segment in Nepal

Traffic crashes are caused by various factors, including vehicle conditions, road geometry, traffic patterns, environmental influences, and human behavior. Each factor contributes to crashes to varying degrees, impacting road safety [14]. Traffic crashes are a leading cause of death in developing countries [15].

Human factors play a significant role and are responsible for the majority of road accidents worldwide [16]. Human factors significantly contribute to RTAs, with non-adherence to traffic rules and law enforcement exacerbating the issue [17, 18]. Driver negligence, lack of attention, young driving, speeding, reckless driving, distracted driving, and driving under the influence of drugs or alcohol [19]. Some major driver-related factors responsible for RTAs are:

Fatigue and Sleepiness: Fatigue and sleepiness are common human factors that can impair driving performance and raise the risk of an accident. Drivers who are tired or sleepy are more likely to make mistakes, react slowly, and have microsleeps.

Aggressive Driving: Another human factor that can lead to RTAs is aggressive driving, which includes tailgating, cutting off other drivers, and aggressive passing.

Lack of Training and Experience: Drivers who lack proper training and experience are more likely to make mistakes and become involved in accidents. This is especially true for inexperienced and young drivers.

Distracted Driving: Distracted driving is a major cause of RTAs. This can include anything that diverts a driver's attention away from the road, such as texting, eating, or adjusting the music.

Speeding Driving: Speeding is a major contributor to RTAs [19]. Overspeeding is defined as driving at speeds exceeding the posted speed limit, increasing the risk of accidents and compromising road safety [20]. Drivers who drive faster than the posted speed limit have less time to react to changing road conditions and are more likely to lose control of their vehicles. Overspeeding significantly increases the risk of injuries and fatalities [21]. In 2019, speeding was responsible for 26% of all road fatalities in the United States, with more than 25 deaths occurring daily [22]. A 1% increase in a driver’s average speed raises their risk of fatal injury by 4% [23].

Impaired Driving: Impaired driving, which includes driving while under the influence of drugs or alcohol, is a major contributor to RTAs. Drivers who are impaired have slower reaction times and poor judgment, which can lead to accidents. Driving under the influence of alcohol is a significant threat to road safety in Nigeria. The maximum authorized BAC is 0.5 g/l, with proposed reductions to 0.2 g/l for novice drivers and 0.01 g/l for commercial drivers. Alcohol impairs vision and judgment, and increases tendencies for speeding, contributing to accidents. It has been demonstrated that laws prohibiting drunk driving reduce the number of alcohol-related accidents. Stricter drunk driving laws and their effective implementation are linked to lower rates of alcohol-related fatalities [24].

Seat Belt Use While Driving: Seat belt laws have been shown to reduce the number of injuries and fatalities in accidents [25]. Seatbelt users have a lower risk of most major RTAs [26].

Cell Phone Use While Driving: Laws prohibiting the use of cell phones while driving can have an impact on road safety. A study conducted in the United States of America revealed that the prohibition on using handheld cell phones while driving is significant in improving traffic safety [27].

2.1 Road infrastructure factors

Road infrastructure factors such as road type, geometric design, traffic control, lighting, and road environment are critical in determining road safety outcomes and significantly influence the occurrence of traffic accidents [28]. Inconsistent road geometry can cause significant variability in speed and introduce unexpected elements for drivers, increasing the likelihood of RTAs [29]. Such irregularities create confusion and affect drivers' ability to react safely [30]. During the early days of motorization, highway design standards advanced with the introduction of design manuals [31]. The road environment significantly influences driver behavior and, consequently, crash rates. Factors such as road geometry, signage, markings, and lighting play crucial roles in shaping drivers' choices and actions. Some of the road infrastructure factors are:

Road Geometry: Road geometry, which includes alignment, gradient, and cross-sectional design, can influence driver behavior. Poor road geometry is a significant risk factor for accidents [32].

Road Conditions: Poor Road conditions, such as potholes, uneven surfaces, and a lack of signage, can also play a role in vehicle accidents. Poor road infrastructure was found to be a significant factor in road accidents in low- and middle-income countries.

Road Signage and Markings: Proper Road signage and markings at hazard locations can help drivers navigate and avoid potential hazards, reducing the risk of accidents [33].

2.2 Weather related factors

Weather conditions such as heavy rain, snow, and fog can heighten the risk of vehicle accidents [34]. Furthermore, rainy weather reduces pavement skid resistance and vehicular stability, such as braking stability and steering operation. Key weather factors influencing crash likelihood and severity include visibility, temperature, wind speed, precipitation, and moisture. These variables are critical as their unpredictable interactions can drastically alter accident probabilities. Considering these factors in road safety measures is essential to minimize risks and enhance driving conditions [35].

2.3 Vehicular factors

Although numerous passive and active safety features have been incorporated into vehicles in recent years, such as airbags and collision warning systems, the incidence of crashes has not diminished. Vehicle mechanical characteristics and driving environment design significantly contribute to road accidents. Poorly maintained vehicles and the absence of modern safety features like lane assist, brake assist, electronic stability control, and Anti-lock Braking System increase accident risks [36]. Additionally, poorly designed driving environments exacerbate driver fatigue, a major factor in vehicle accidents, particularly in heavy-duty vehicles. Driver fatigue results from prolonged driving in suboptimal conditions, affecting both commercial and passenger vehicle drivers [37]. Improving vehicle maintenance standards and incorporating advanced safety features, along with designing ergonomic driving environments that minimize fatigue, are essential to enhancing road safety and reducing accident rates.

Geometric deficiencies on roads can affect driver behavior, potentially leading to RTAs. Poor road design or conditions may influence drivers' decisions, increasing the risk of accidents [38]. Human error, including speeding, distractions, alcohol consumption, traffic rule violations, fatigue, and drowsiness, is a primary cause of RTAs. According to study [4], cell phone use while driving is a major distraction, reporting a significant increase to 11% over the past decade. They emphasize that mobile phone usage raises the likelihood of road accidents by four times. Research carried out [39] shows that about 25% of road accidents involving heavy trucks and passenger vehicles result from driver distractions caused by mobile phones. A study [40] investigated distractions among novice and professional drivers using accelerometers and cameras. Their findings identified risky behaviors like eating, calling, or texting as significant contributors to road accidents. These activities notably increase accident risks, especially among inexperienced drivers.

Factors contributing to RTAs in low- and middle-income countries are driver behavior, inadequate road infrastructure, poor vehicle maintenance, and a lack of traffic law enforcement [10]. The author also emphasizes the significance of addressing social and cultural factors like attitudes toward road safety and risk-taking behavior. Driver behavior, such as speeding and reckless driving, road infrastructure, such as poor road design and maintenance, vehicle-related factors, such as defective brakes and tires, and environmental conditions, such as weather and visibility, were all major contributing factors [41]. The study highlights the importance of targeted interventions aimed at reducing the specific causes of RTAs in different contexts, as well as the need for a comprehensive approach to road safety that addresses these multiple factors. Poor road infrastructure, insufficient traffic management, driver behavior, vehicle defects, and environmental conditions are the major factors contributing to RTAs [42]. They also emphasize the need for additional research to better understand the causes of RTAs, as well as to develop effective interventions to prevent or reduce the occurrence of accidents. Similarly, several key factors, including driver behavior, vehicle design, road design, and environmental conditions such as weather and lighting, are responsible for RTAs [43].

To reduce the risk of accidents, this study focuses on the importance of designing and maintaining safe road environments, improving driver education and training, and developing effective policies and regulations. Likewise, driver-related factors, such as speeding, distraction, and impaired driving, were found to be the most frequent causes of serious road accidents [44]. To improve road safety, targeted interventions that address the underlying causes of traffic accidents, along with comprehensive road safety policies that address the multiple causes of RTAs, such as improving driver education and training, improving vehicle safety features, and upgrading road infrastructure, are vital [26].

The analysis presented in Table 6 reveals that multiple demographic and contextual factors significantly influence the likelihood and nature of RTAs on Nepal’s highways. A clear pattern emerges, showing that the type of bus driven, whether tourist, big, mini, or micro bus, affected specific risk factors, suggesting that safety interventions should be tailored to vehicle types. For instance, the significant F-values associated with variables such as drunk driving, loud music/headphones, unhealthy competition between buses while driving across bus categories highlight how operational differences impact RTAs causes. Policymakers should thus consider differentiated regulatory frameworks, including vehicle-specific maintenance protocols and driver training modules tailored to each bus category.

Education level also plays a critical role in accident patterns, as indicated by significant variations among drivers with Bachelor’s degrees, SEE/SLC, and qualifications below SEE/SLC. This suggests that driver education programs need to be customized based on educational backgrounds. For example, drivers with higher education levels who the study found more prone to risky behavior may benefit from advanced defensive driving and risk perception training, while drivers with lower educational attainment may require foundational training focused on hazard awareness and infrastructure navigation. Implementing tiered educational programs could enhance overall road safety outcomes.

Age and driving experience further influence accident risks, with younger drivers showing higher vulnerability to distractions and risky driving, and older drivers struggling with challenging road conditions. Drivers with varying years of experience also demonstrate differences in their exposure to significant factors such as speeding and fatigue. This emphasizes the need for continuous professional development and refresher courses that address age- and experience-specific risks. Licensing authorities should consider mandatory periodic assessments that reflect these demographic variations, ensuring that drivers maintain competencies appropriate to their age and experience level.

The temporal analysis of RTAs occurrences by time of day and season highlights high-risk periods such as early mornings, festive seasons, and the rainy season. These findings indicate that temporal factors must be integrated into road safety planning. For instance, increased traffic enforcement, targeted awareness campaigns, and enhanced road maintenance should be prioritized during this critical time. Seasonal infrastructure adaptations, such as improved drainage and fog-resistant signage, could mitigate weather-related risks during the monsoon and winter months.

The current research and prior studies share significant similarities, particularly regarding the dominant role of human behavior in RTAs. The study [46] highlighted that over 70% of RTAs are attributed to human factors, aligning with the current research’s focus on speeding, reckless driving, and drunk driving as key contributors. Both studies emphasize the importance of driver behavior in accident causation. Similarly, the study [41] underscore the impact of vehicle defects such as faulty brakes and tires, which is consistent with the current study’s findings on the role of defective vehicle components in RTAs. Environmental factors such as adverse weather conditions and poor visibility are common factors. The current research finds that weather-related issues, like rain and fog, significantly contribute to road accidents, reflecting the environmental concerns identified by the study [41]. Additionally, both studies recognize infrastructure-related issues, such as poor road surfaces, narrow roads, and inadequate signage, as contributing to accidents. Moreover, both studies stress the importance of addressing these factors through targeted interventions to improve road safety.

Unlike previous research that generally addresses RTAs at national or global levels, this study provides localized, context-specific insights. It uniquely explores how different types of buses tourist, big, mini, and micro perceive with various risk factors, highlighting operational differences rarely examined before. Additionally, the study investigates the influence of driver demographics such as education, age, and years of experience on road accident risks, revealing nuanced patterns, including that higher-educated drivers may engage in riskier behaviors. Temporal factors, including time of day and seasonal variations, are also integrated to better understand RTAs trends. By combining these dimensions, the research offers a comprehensive and detailed understanding of RTAs in Nepal, providing evidence-based recommendations for tailored road safety interventions and policy development specific to the country’s unique traffic environment.