Introduction

Road traffic injury (RTI) is defined as physical damage sustained by a person as a result of a road traffic incident/Crash [1]. Road crashes and deaths are becoming a matter of serious concern and a major public health problem with the increasing number of deaths, hospitalizations, and disabilities, especially among the productive young population [2]. RTIs cause widespread harm, ranking ninth globally in disability-adjusted life years (DALY) lost [3].

According to WHO, Motorcycles, scooters, and e-bikes are at higher risk of RTI, accounting for 30% of all road traffic deaths in 2022 [4]. Injuries are disproportionately high among males, disadvantaged groups, and young adults aged 15–29 years, particularly in road crashes, where disadvantage groups include low-income individuals, informal workers, rural residents, where they face elevated risk due to limited access to safety infrastructure, protective gear, legal protections and emergency services [4]. Over the past decade, Nepal has seen a dramatic increase in vehicle registrations [5]. In 2011, registrations surged by 325%, with 85% of newly registered vehicles being two-wheelers. By 2021, motorcycle registrations reached an all-time high of 556,819 units, reflecting the growing preference for two-wheelers as a primary mode of transport. This trend highlights the increasing accessibility and demand for personal vehicles, particularly motorcycles, across the country. [6,7]

Despite road safety data being gathered from multiple sources, including police reports, traffic records, insurance databases, and hospital reports, under-reporting remains a significant issue, particularly in Nepal and India, limiting a comprehensive understanding of the true burden of RTIs [8–10]. The primary sources, traffic police records and hospital data, often fail to capture the full extent of RTIs due to limitation in epidemiological, economic, and risk factors [11]. As a result, RTIs remain inadequately recognized as a critical public health issue, with gaps in data visibility hindering meaningful policy interventions [10,11]. This mixed-method study aims to assess the prevalence, risk factors and underlying mechanisms of RTIs among undergraduate two-wheeler drivers in Kathmandu. Additionally, it seeks to evaluate health-seeking behaviors, estimate the broader impacts of RTIs, and identify key recommendations derived from qualitative analysis.

Methodology

The quantitative study was conducted in four Kathmandu University-affiliated colleges in Kathmandu from December 2020 to February 2021. The ethical approval was obtained from Nepal Health Research Council (289) and the Institutional Review Committee of Kathmandu Medical College, reference number (1009210917) The permissions were taken from the principal, program coordinators and from the administration department to obtain the list, the phone numbers, and email addresses of the students and the college informed the students regarding the study. The data were collected from students enrolled in first to fourth year, spanning 28 classes from 4 academic institutions: Kathmandu Medical College, Nepal Medical College, National college and St. Xavier’s College.. It covered diverse streams including Medicine, Dental, BSc Nursing, Development Studies, Finance, and bachelor’s in social work.

The questionnaire was emailed to all 1,879 students across the 28 classes with two reminders sent weekly for two weeks. After two weeks the survey was closed. The participants gave online informed consent and participation in the study was voluntary.

All the students who use a two-wheeler irrespective of driving license currently studying in four colleges were included in the study and those participants who ride two-wheelers who did not give consent and cycle riders were excluded.

For the qualitative data 5 key informant interviews (KII) were conducted including the senior college program coordinator, emergency physician, traffic police officer, former Director-general of the Department of transport management, and judge They were informed about the study, and it was recorded only after they gave written consent. The interview was conducted in the Nepali language and lasted about 15–20 minutes. The qualitative component of this study was explicitly designed to elicit recommendations for reducing RTI from key stakeholders. The interview guide was structured around this purpose, and participants were asked to provide their perspectives on actionable strategies.

This study employed explanatory sequential mixed‑methods design. In the first phase, quantitative data was collected and analyzed to determine the prevalence of RTI and associated risk factors. The second, qualitative phase was informed by these findings and involved five key informant interviews to generate contextual recommendations to reduce RTI. The integration of both strands allowed quantitative results to establish the burden of RTIs, while qualitative insights provided stakeholder perspectives and actionable strategies.

Results

The total number of students studying in these colleges was 18,798, out of which 1,217 responded, giving a response rate of 64.8%. Among the 1,217 respondents, 579 (52.4%) used two‑wheelers. The participants ranged from 17 to 31 years and 308 (65.6%) were male respondents. The most used two‑wheeler was motorcycle (330, 57.0%) followed by scooter (249, 42.7%) (Table 1).

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Table 1. Age, institution and driving experience and license details of the undergraduate students who use two-wheelers (n = 579).

https://doi.org/10.1371/journal.pone.0341275.t001

Out of 579 two‑wheeler users, 218 (37.6%) reported road traffic incidents and among them, 49 (31%) had multiple incidents, and 19 (3.2%) experienced more than three. However, only the most recent incident per respondent was considered, regardless of severity. Not all road traffic incidents necessarily led to RTI; when enquired further, only 135 (23.3%) out of 218 incidents resulted in RTI. Among the 135 respondents who sustained injuries, 79(58.5%) were male and 56(41.5%) were female. These injury details corresponded only to two‑wheeler drivers and did not include pillion passengers. Pillion riders were present in 139 (24%) of incidents, and 99 (71%) sustained minor injuries, but no fatalities were recorded.

October was the most common month for incidents (40, 18.3%), while the majority occurred over weekends (74, 33.8%), nearly half (107, 49.3%) between 12 PM and 6 PM, and (98, 45%) on the ring road, particularly in Chabahil, Koteshwor, and Gwarko. Collisions accounted for 119 (54.4%) of incidents, with 100 (45.6%) involving another two‑wheeler. Speeding (76, 34.8%) and sudden braking by another driver (47, 21.7%) were leading causes. Non‑collision incidents (99, 45.6%) were mainly due to vehicle slip (48, 48.6%) and imbalance (45, 45.8%). Mechanical defects in the two‑wheeler were reported by 18 (8.3%) of respondents.

Out of the 135 RTIs, 769 injuries were recorded as some respondents sustained multiple injuries. Lower limbs were most affected, including the knee (91, 11.8%) and lower leg (90, 11.7%), while elbow injuries (77, 10%) were common in upper limbs. Bruises (328, 42.6%) were most frequent, followed by sprains (192, 25%), fractures (75, 9.7%), and joint dislocations (39, 5%).

Out of all incidents, more than half of respondents (139, 64%) required treatment. Nearly half (102, 47%) opted for the emergency room. Of the 11 respondents who needed further management, 9 (84.6%) required admission, and 6 (53.5%) were admitted for 5 days, with the maximum duration being 1 week.

More than half of respondents (91, 57%) reported disability after the injury. The majority (118, 74.5%) could not perform regular activities for less than 1 week.

Financial impacts were also evident. Half of the respondents (79, 50%) paid up to NPR 1,000 for treatment, mostly for bruises. Nearly (14, 9%) paid up to NPR 50,000 for more serious injuries. The healthcare cost ranged from NPR 200–70,000, with a median of NPR 1,350 and IQR of NPR 4,425. Insurance covered costs for 47 (30%), whereas 108 (70%) paid out of pocket. In addition, 58 (40%) incurred repair costs for their two‑wheelers, ranging from NPR 1,000–125,000.

As undergraduate students, respondents also experienced educational impacts. (96, 66.6%) took leave for less than 1 week, whereas (27, 19%) took leave for more than 2 weeks. The median and IQR for leave days were 7 and 10 days respectively, with a range of 1–28 days. (2, 9.6%) missed examinations due to injuries.

Association between respondent’s attributing factors with RTI among two wheelers using bivariate and multivariate analysis

The study identified key factors associated with RTIs. (Table 2) The Crude odd’s ratio demonstrated that males were more likely to sustain RTIs than females, and scooter users demonstrated a significant association with RTIs. Riders with 4–6 years of driving experience were at higher risk. All the associations were found to be statistically significant. It was followed by multivariate analysis.

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Table 2. Adjusted odds ratio with various variables of the respondents with RTI (n = 579).

https://doi.org/10.1371/journal.pone.0341275.t002

The multivariate analysis highlighted that male had higher odds of RTIs compared to females, and motorcycles were significantly associated with increased risk. Riders with 4–6 years of experience showed reduced odds.

The qualitative section was complemented by 5 key informants’ interview were conducted with experienced stakeholders including senior college program coordinator, emergency physician, traffic police officer, former Director-general of the Department of transport management, and judge. These interviews were specifically designed to gather expert recommendations on reducing RTIs. A major strength of this study lies in the depth of insights provided by the informants, whose perspectives have been refined into 5 overarching themes as summarized in Table 3.

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Table 3. The themes and recommendations from the qualitative study.

https://doi.org/10.1371/journal.pone.0341275.t003

Together, these themes highlight a multi‑layered approach to road safety: early education to instill discipline, infrastructure and transport reforms to reduce risk exposure, stronger enforcement by traffic police, legal reforms to deter risky behaviors, and licensing reforms to ensure competency. The verbatim quotes provide the rationale behind each recommendation, grounding them in stakeholder perspectives and reinforcing their relevance to policy and practice.

Discussion

This study examined RTIs among undergraduate two-wheeler users in Kathmandu. Most RTIs occurred between 12 PM and 6 PM, aligning with patterns observed in Nepal and India [12–14]. The time frame coincides with peak traffic hours, and key informants including traffic police and emergency physicians confirmed that the two-wheeler incidents are frequently reported during these hours, reinforcing the need for time targeted enforcement and awareness.

Injuries between 6–10 PM may be linked to driver fatigue, as seen in studies from China and Croatia [15,16]. Weekend incidents were more frequent, possibly due to increased travel activity, speeding and reduced traffic congestion [14–16]. This pattern is consistent emergency room data from Nepal [17,18] as with global trends as mentioned by WHO [2].

RTI concentration in October likely coincides with festive travel during Dashain and Tihar [19] which highlights the needs for different traffic management strategies around those months. Informants emphasized that festive periods bring increased mobility and risk suggesting that traffic police should intensify monitoring and during these months.

Collision data revealed that 46% of incidents involved another two-wheeler and was found similar in studies in Kashmir India but slight less was found in another study done in Nepal [20,21], reinforcing the vulnerability of motorized two-wheelers in urban traffic ecosystems. Informants consistently attributed this to reckless driving and poor adherence to traffic rules, particularly among young riders. Their recommendations included road safety education into school curriculum and launching targeted campaigns over time to reinforce the emphasis on human behavioral factors.

Mechanical defects, though reported by only 8.3% of riders, mirror findings from Kathmandu-based studies [21–22] and underscore the importance of regular vehicle inspections. Informants highlighted gaps in vehicle maintenance and called for stricter inspection protocols. These align with WHO’s on two-wheeler safety which emphasizes on vehicle conditions and enforcement of vehicle standards and regular inspection [4].

Injury patterns showed the upper limb was most affected (49.9%), followed by lower limb injuries (39.4%), also found consistent with studies in Nigeria, Nepal, and Laos [23–25]. The predominance of bruises (42.6%) and sprains (25%) [26–29] suggests that while many injuries are minor, their cumulative impact on academic performance and financial stability is substantial. Nearly 13.3% of respondents took leave from college post-injury and treatment costs ranged from NPR 1,000 to NPR 50,000, with 60% paying out-of-pocket. Notably, vehicle repair costs often exceeded healthcare expenses, this economic strain is echoed in studies from Vietnam, Bangladesh and Nepal [30–33]. WHO has also mentioned that economic impact is disproportionally high pushing families into poverty due to high out of pocket expenses [4].

Strengthening the role of traffic police was also seen as a critical point. The informants recommend random license checks, stricter enforcement of speed limits and equipping officers with real- license verification tools. They also stressed the importance of political interference to ensure consistent application of rules for everyone. These suggestions align with the best global practices outlined in WHO road safety manual [1,3] and road safety charter and European transport safety council (ETSC) [34–36].

Legal reforms were also found essential as suggestions included increasing age limit for license eligibility, implementation of suspension for violations and enforcing use of helmet use for both riders and passengers. Informants argued that the penalties should be proportionate to severity of negligence. These suggestions align with the WHO recommendations for graduated licensing system and stricter penalties for risky behaviors [4]. The licensing system was also identified as areas where reforms were necessary. They advocated for a learner’s permit system that included a supervised driving period before attaining full license, these again align with the global best practices [4].

The quantitative findings of this study highlighted the scale and nature RTI among two‑wheeler users in Kathmandu. Patterns in injury mechanisms, types of injuries sustained, and the duration of license holding and driving experience revealed important risk factors. These data also underscored the significant health and financial burden, with high out‑of‑pocket expenditures, frequent disability, and disruption of education. Such evidence provides a strong basis for targeted intervention and improved post‑crash care, ensuring that the burden of RTI doesn’t disproportionately fall on students and their household.

The qualitative insights complemented these findings by offering stakeholder‑driven recommendations. Informants emphasized shared responsibility across road users, policymakers, enforcement agencies, and the health system, aligning with global Safe System principles. [5] They called for reducing dependency on two‑wheelers through stronger public transportation, fiscal measures such as pollution and vehicle taxes, stricter enforcement of traffic laws, and reforms in the licensing system. Together, these perspectives highlight that addressing RTIs among young riders requires both data‑driven interventions and systemic reforms, ensuring safer roads, equitable health financing, and coordinated multi‑sectoral action

Supporting information

Acknowledgments

We would like to thank all the undergraduate who contributed to our studies as participants, students along with Dr. Nishchal Dhakal, Mr. Ujjwal Upadhyay, Father Augustine Thomas for providing me the necessary support to conduct the study in their respective colleges. We would also like to thank the 5 key informants who provided their valuable time and experience without whom the research would not have been completed.