Retrospective Study to Compare Injury Patterns and Associations in 170 Patients Following Electric Scooter and Bicycle Accidents in Turkey

Introduction

Urban mobility has evolved dramatically in recent years, with micromobility becoming a rapidly expanding part of modern daily transportation routines. Studies have highlighted the growing popularity of electric scooters as a key component of micromobility, particularly in urban environments, due to their convenience and adaptability to traffic conditions [1]. Traffic congestion in metropolitan areas, along with increasing collective awareness of environmental issues, has encouraged this rapid development [2,3]. Electric scooters (also called “e-scooters”) have gained popularity, as they offer fast travel and the ability to avoid traffic jams thanks to their compact size [4]. In Eskişehir, e-scooter rentals started in April 2021, while the use of bicycles has a much longer history [5].

Apart from the convenience that e-scooters provide, they are known to have introduced new safety problems. Studies conducted in the United States, where e-scooters have become a part of urban life, have shown that fractures (26–32%) and head injuries (28–40%) are related to e-scooter accidents [6–8]. These findings were also observed in studies conducted in Denmark, Germany, and Turkey [9–11]. The rapid global adoption of e-scooters has been accompanied by a notable increase in injuries. Studies from various countries have shown that orthopedic injuries, particularly fractures of the upper and lower extremities, are among the most common trauma types associated with e-scooter accidents [1,12,13]. However, varying legal regulations in different countries make it difficult to compare the traffic situation on Turkish roads. In Turkey, it is not mandatory to wear protective equipment or have a driver’s license when using e-scooters, but it is forbidden for those under the age of 15 years to use them, to use them on sidewalks, to have more than one person on the scooter, and to exceed a speed of 25 km/h [14]. While bicycle users in Turkey commonly use designated bicycle paths, e-scooter users often prefer sidewalks and highways. These behaviors significantly increase the likelihood of accidents. A study conducted in Turkey emphasized that the absence of proper infrastructure for e-scooters frequently forces riders onto sidewalks and vehicle lanes, exacerbating safety concerns [11]. In a retrospective study by Şenel et al, involving 534 patients with e-scooter-related injuries in Turkey, it was reported that the most common cause of trauma was loss of balance, which accounted for 80% of the cases [12]. This emphasizes the critical role of stability and balance in e-scooter safety. The lack of adequate user training or protective measures, combined with insufficient infrastructure, significantly exacerbates the risk of accidents. In alignment with these findings, our study aims to further investigate how such infrastructural and behavioral factors influence injury patterns in Eskişehir, Turkey.

The necessity of this study is justified by the limited research on the integration of e-scooters on Turkish roads and the ongoing debate surrounding this mode of transportation. This retrospective study aimed to analyze and compare injury patterns, associations, and severity levels in e-scooter and bicycle accidents, based on data from 170 patients admitted to an urban emergency department in Eskişehir, Turkey.

Material and Methods

ETHICAL APPROVAL:

Patient data were obtained from the hospital database in compliance with the Turkish Personal Data Protection Law. Ethical approval was granted by the Eskişehir Osmangazi University Faculty of Medicine Ethics Committee, which waived the need for informed consent due to the retrospective nature of the study. The study adhered to the principles outlined in the Declaration of Helsinki.

STUDY DESIGN AND SETTING:

The study was conducted in Eskişehir, Turkey, a city with a population of approximately 900 000. A retrospective analysis was performed on patients referred by the prosecutor’s office to the Eskişehir Osmangazi University Faculty of Medicine, Department of Forensic Medicine, for a forensic report after involvement in e-scooter or bicycle accidents between April 2021 and December 2023.

PATIENTS AND INCLUSION CRITERIA:

All e-scooter and bicycle riders injured in traffic accidents during the study period were included in the study. No exclusion criteria were applied. The following variables were analyzed: age, sex, occupation (student or non-student), time interval, day, month, year, rider category (e-scooter or bicycle), accident location, use of protective equipment (helmet), mode of admission, accident mechanism, site and type of injury, alcohol or drug use, hospitalization, and radiological imaging.

STATISTICAL ANALYSIS:

Statistical analyses were performed using SPSS 27 (Statistical Package for the Social Sciences). Descriptive statistical methods (mean, standard deviation, median, frequency, percentage, minimum, and maximum) were used to evaluate the study data. The relationships between the type of vehicle used, demographic characteristics, post-accident actions, and accident-related features were analyzed using the Pearson chi-square test, Fisher exact test, and Fisher-Freeman-Halton test. A P value of <0.05 was considered statistically significant.

Results

DEMOGRAPHIC CHARACTERISTICS OF PATIENTS:

The study included 170 patients, of which 54 were e-scooter riders and 116 were bicycle riders. The mean age of the e-scooter riders was significantly younger than that of the bicycle riders (21.96 years, SD±10.07 vs 30.03 years, SD±20.93; P=0.001). Female patients were more prevalent among e-scooter riders (24.1%) than bicycle riders (12%; P=0.019). Most of the e-scooter patients (53.7%) and bicycle patients (44.8%) were students.

ACCIDENT CIRCUMSTANCES:

Among e-scooter riders, 25.9% had passengers during the accidents, compared with 11.2% of bicycle riders (P=0.021). Both groups recorded 3 injured pedestrians (e-scooter: 5.6%, bicycle: 2.6%). Most accidents occurred on weekdays (e-scooter: 81.5%, bicycle: 75%) and in the afternoon (e-scooter: 48.1%, bicycle: 39%), although cyclists were more likely to have accidents at night. Regarding seasonal distribution, there was no significant difference between the e-scooter accidents and the bicycle accidents (P=0.093).

Accidents predominantly occurred on the street for both groups (e-scooter: 85.2%, bicycle: 91.4%), but 7.4% of e-scooter accidents occurred at pedestrian crossings, compared with no bicycle accidents (P=0.022). Helmet use was not observed among e-scooter riders, whereas 11.2% of bicycle riders used helmets (P=0.010).

The primary mechanism of injury in both groups was motor vehicle collisions (e-scooter: 68.5%, bicycle: 79.3%), followed by falls (e-scooter: 16.7%, bicycle: 12.1%; P=0.379). Both groups mostly travelled to the emergency department by their own means (e-scooter: 63%, bicycle: 62.9%) (Table 1).

PATTERNS OF INJURY:

Head injuries were more frequent among e-scooter patients (44%) than bicycle patients (36.4%), but this difference was not statistically significant (P=0.420). Brain contusions were the most common head injuries in both groups (e-scooter: 45.8%, bicycle: 36.4%), followed by traumatic brain injuries (TBI; e-scooter: 37.5%, bicycle: 29.5%). Among patients with head trauma, intracranial hemorrhage was observed in 9.5% of e-scooter patients and 25% of bicycle patients, but this difference was not statistically significant.

Facial injuries were also prevalent in both groups, with soft tissue injuries being the most common type (e-scooter: 60.0%, bicycle: 51.0%). Fractures of facial bones occurred more frequently among bicycle patients (19.6%) than e-scooter patients (10.0%). Dental injuries were slightly more common in e-scooter patients (13.0%) than in bicycle patients (9.5%), but this difference was not statistically significant (P=0.492).

Chest injuries were exclusively observed in bicycle patients, with 5 patients sustaining fractures and 2 patients experiencing pneumothorax. Similarly, spine fractures were observed only in bicycle patients (6 patients), while no spine fractures occurred in e-scooter patients (P=0.433). Pelvic fractures were rare and reported in only 1.7% of bicycle patients.

Upper extremity fractures were more common than lower extremity fractures in both groups. However, total fractures were significantly higher in bicycle patients (47%) than in e-scooter patients (28%, P=0.020). Dislocations were observed in 6% of e-scooter patients and 11% of bicycle patients, but this difference was not statistically significant (P=0.240; Table 2).

Alcohol use was significantly higher among e-scooter riders (18.5%) than among bicycle riders (4.3%; P=0.006). Among e-scooter users involved in alcohol-related accidents, the reported injuries included 1 head fracture, 2 head contusions, 1 TBI, 2 facial contusions, and 2 facial fractures. In alcohol-related accidents involving bicycle users (n=5), the reported injuries included 1 head fracture, 1 head contusion, 1 TBI, 1 facial contusion, and 1 facial fracture. While the injury types appear somewhat comparable, the small sample size of alcohol-positive bicycle riders limits the statistical power to draw definitive conclusions. Nonetheless, the data suggest that alcohol consumption is associated with increased injury severity and complexity in both e-scooter and bicycle users.

IMAGING AND HOSPITALIZATION:

Radiological imaging was performed in 68.5% of e-scooter patients and 84.5% of bicycle patients, with a statistically significant difference between the groups (P=0.017). X-rays were the most commonly used imaging modality (e-scooter: 42.6%, bicycle: 47.4%, P=0.557), followed by computed tomography (CT) scans (e-scooter: 25.9%, bicycle: 33.6%, P=0.313). Magnetic resonance imaging was rarely used in either group, with 1.9% of e-scooter patients and 3.4% of bicycle patients undergoing this procedure (P=0.999). Cranial computed tomography scans were performed in 5.6% of e-scooter patients and 8.6% of bicycle patients (P=0.728).

Most patients in both groups were discharged as outpatients after receiving initial treatment. Hospital admission rates were low and comparable between the groups, with 7.4% of e-scooter riders and 5.2% of bicycle riders requiring hospitalization (P=0.715). Among admitted patients, the mean hospital stay was slightly longer for bicycle patients (4.3±4.1 days) than for e-scooter patients (3.2±3.5 days), although this difference was not statistically significant (P=0.072; Table 3).

TREATMENT AND OUTCOMES:

Surgical interventions were required more frequently in e-scooter patients (20.4%) than in bicycle patients (9.5%), although this difference was not statistically significant (P=0.232). Intensive care unit admission was rare in both groups, with 3.7% of e-scooter patients and 5.2% of bicycle patients requiring intensive care.

Wound management procedures, such as sutures and dressings, were performed in 16.7% of e-scooter patients and 12.1% of bicycle patients (P=0.467). Plaster cast or brace treatments were applied more often for bicycle injuries (15.5%) than for e-scooter injuries (9.3%). Most patients in both groups were discharged with outpatient follow-up plans (e-scooter: 50.0%, bicycle: 57.8%; Table 3).

Discussion

STRENGTHS AND LIMITATIONS:

One of the primary strengths of this study is the use of a large dataset spanning an extended timeframe, which provides a comprehensive overview of e-scooter and bicycle related injuries. This dataset offers valuable insights into injury patterns, particularly within a city that has seen regulatory changes in response to increasing accident rates. Notably, this study is the first to analyze accident data within this evolving regulatory context, providing a unique perspective on the potential impacts of such interventions.

This study, however, has several limitations. The retrospective design inherently relies on pre-existing records, which can introduce biases such as incomplete documentation or the omission of relevant variables, including detailed accident mechanisms and patients’ pre-existing medical conditions. Additionally, the small sample size of alcohol-positive bicycle users limits the generalizability of findings concerning alcohol consumption and injury severity. The study’s geographical focus on a single city (Eskişehir, Turkey) can also restrict the applicability of findings to other regions with varying traffic infrastructures, cultural norms, or regulatory frameworks. Furthermore, the absence of mandatory helmet use among e-scooter users and the lack of detailed data on protective equipment use by bicycle users may have influenced the observed injury patterns.

Methodological limitations also warrant consideration. The reliance on hospital records and forensic reports may result in underreporting of less severe injuries that did not require medical attention. Moreover, statistical analyses were constrained by the uneven sample sizes between e-scooter and bicycle users, particularly among alcohol-positive individuals, potentially impacting the robustness of group comparisons. These limitations underscore the need for prospective, multicenter studies with larger sample sizes and standardized data collection methods to provide more reliable and generalizable insights into injury patterns and risk factors associated with e-scooter and bicycle use.

Conclusions

The findings from this study indicate that the safety issues faced by e-scooter riders, other road users, and pedestrians differ significantly from those associated with bicycle riders. E-scooter users demonstrated higher rates of head injuries and alcohol consumption, whereas bicycle users experienced a higher prevalence of fractures. These findings emphasize the urgent need for targeted safety interventions, including mandatory helmet use, enhanced urban infrastructure, and stricter enforcement of traffic regulations, to mitigate the increasing rates of accidents involving urban e-scooters.