1. Introduction
Traffic accident is one of the most critical global health issues considered the ninth cause of death in the world [1, 2]. Traffic accident is the main cause of death for people aged 5-29 worldwide and also 1.35 million people die due to traffic accidents in the world each year [3]. According to the World Health Organization (WHO) report, low- and middle-income countries accounted for 93% of deaths due to the traffic road [3]. In Iran, traffic accident is the second cause of death, followed by cardiovascular diseases [4]. The rate of traffic accidents in Iran is high about 17.7% of all deaths. Among the Eastern Mediterranean countries, Iran has the highest car per capita (one car per 4 people) [5]. According to research, road accidents impose direct costs on society [6]. It is estimated that traffic accidents impose a financial burden of more than $ 518 billion on countries around the world, accounting for an average of 1% to 5%of the gross domestic product [7]. The young and the middle-aged people are mostly exposed to traffic accidents that lead to the loss of the active labor force; therefore, it imposes costs on society indirectly [6, 8, 9]. On the other hand, it has been reported that men are the most victims of the road accident which negatively affects the family economy [8, 10].
The total length of roads in Iran is 570,000 km [8] and most accidents occur on the main and suburban roads [8, 11] then considering the importance of prevention at the primary level, the United Nations General Assembly focuses on the maximum reduction in injury and mortality due to road accidents in the world by 2030 [3]. Therefore, the causes and effective factors in the occurrence of accidents can be identified and it is possible to reduce the number of road accidents by implementing preventive policies, and it is necessary to identify the factors leading to traffic accidents. No comprehensive and reliable information is available about road accidents in Torbat Heydariyeh City. Since Torbat Heydariyeh City is located on the road to Mashhad City, Iran, the traffic in this city is high. Therefore, this study was conducted with the aim of the epidemiological assessment of deaths caused by road accidents in Torbat Heydariyeh between 2013 and 2017.

2. Materials and Methods
This cross-sectional study was conducted with the aim of the epidemiological evaluation of deaths caused by road accidents in Torbat Heydariyeh City between 2013 and 2017. 
The code of ethics (IR.THUMS.REC.1397.031) was obtained from Torbat Heydariyeh University of Medical Sciences. Then, the information on fatal accidents recorded between 2013 and 2017 was collected by Forensic Medicine Organization. Variables included exact time of accident and death (hour, day, month, and year), gender, age, marital status, place of residence, occupation, education, road lighting, the scene of the accident, injured body parts, the final cause of death, place of death, condition of the deceased at the time of the accident, how the accident occurred, type of vehicle used by road accident victims, type of vehicle collided with road accident victims. The data were available in an Excel file so this software was used to analyze the data. To describe qualitative and quantitative variables, the frequency and Mean±SD were used, respectively. 
3. Results
A total of 311 fatal accidents have been reported from Torbat Heydariyeh between 2013 and 2017. Table 1 presents demographic information. The number of deaths recorded in the Forensic Medicine Organization of Torbat Heydariyeh and Mashhad was 214 (69%) and 97 (31%), respectively.



The scenes of the accident were suburban, urban, and rural roads and also unknown with the frequency of 134 (43%), 54 (17%), 9 (3%), and 114 (37%), respectively. The highest percentage of urban accidents occurred on the main street with 19% (60 cases) and the highest percentage of suburban accidents occurred on the main road with 50% (154 cases). 
The highest and the lowest percentages of road accidents accounted for 24% (76 cases) in 2016 and 17% (52 cases) in 2013, respectively. In addition, the highest number of accidents was in August with 40 cases (13%) and the lowest number of accidents was in February with 17 cases (6%) (Figures 1 and 2).







In terms of road lighting, 186 (60%) of road accidents occurred during daylight hours, 93 (30%) accidents occurred at night, and 32(10%) accidents occurred at sunrise or sunset. By dividing a day into four parts, most fatal accidents occurred in the third six hours between 12 PM and 6 PM (Table 2).



The most injuries were related to the head and face at 48% (148 cases), then to the head, face, chest and abdomen, hands and arms with 8% (24 cases), and finally to the chest and abdomen with 7% (22 cases). The final cause of death was due to head injury with 41% (128 cases), multiple fractures with 33% (103 cases), and bleeding with 9% (26 cases). A total of 151 individuals (49%) died at the hospital, 138 individuals (44%) at the scene of the accident, and 22 individuals (7%) on the way to the hospital.
The majority of those who died in the accident were passengers with 42% (130 cases), then drivers with 41% (126 cases), and pedestrians with 17% (55 cases).
The number of vehicles collided with each other, vehicles collided with a pedestrian, vehicles overturned, and those collided with a fixed object was 148 (48%), 57 (18%), 85 (27%), and 21 (7%), respectively.
Motorcycles with 25% (77 cases), then pedestrians with 18% (55 cases), Pride car with 16% (51 cases), Peugeot 405 car with 11% (33 cases) allocated the highest percentage.
The percentages of vehicles that collided with the victims were Pride cars with 10% (30 cases), road construction vehicles with 10% (31 cases), Mercedes- Benz trucks with 8% (25 cases), as well as 71 cases of overturning of the victims’ car (23%).
The results of the chi-square test indicated a significant relationship between the place of death and injured body parts such as the head, face, chest, abdomen, hands, and arms (P=0.049). Most deaths occurred at the hospital. In other cases, most deaths occurred at the scene of the accident (Table 3).



No statistically significant relationship was observed between the place of death and the type of vehicle (P=0.956), gender (P=0.811), and distance from the city (P=0.395).
4. Discussion 
In the present study, the epidemiology of deaths caused by accidents in Torbat Heydariyeh between 2013 and 2017 was examined. During this period, 311 fatal accidents were reported. The Mean±SD age of the deceased was 39.55±22.71, the highest frequency (37%) was in the age group of 20-40 years. The most common cause of death was due to a head injury (41%) and the majority (42%) of those who died in the accident were passengers. And motorcycles were reported to be the most accident-prone (25%). The results of the present study show that deaths due to road accidents had a decreasing-increasing trend and most of the deaths occurred in 2016, especially between March and August. Rezazadeh et al conducted a study that showed a declining trend in road accidents from 2009 to 2019 [12]. Japan and Turkey also indicated a declining trend in road accidents in recent years [13, 14]. A reduction in accidents can be attributed to the increase in road control, including speed control.
Based on the findings of the present study, the highest mortality occurred in the age group of 20-40 years and the Mean±SD age of the deceased was 39.55±22.71 years. Abedini conducted a study that reported that the majority of road accidents occurred in the 19-36 age groups [9]. In addition, a study conducted by khorami indicated that most fatal road accidents occurred between young and middle-aged people [15]. However, in another study by Nasiri, the highest number of deaths due to road accidents was reported in the age group of 19-30 years, which is inconsistent with our results [16]. This age group is at risk of road accidents due to risky and emotional behaviors as well as higher speed. On the other hand, this group is of working age; therefore most road accidents threaten them. If they have an accidents, it can impose an economic burden on society.
In the present study, most of the deceased were self-employed and had a diploma or lower level of education and even 20% of them were illiterate. In other words, the higher the level of education, the fewer fatal road accidents. The results of a study by Khorami in Fars Province, Iran, were consistent with our study [15].
In studies conducted in Turkey and China, fatal accidents have also decreased by increasing the education level [17]. In a study conducted in India, nearly a quarter of the victims were illiterate, which is consistent with the results of the present study [18]. It can be explained that drivers with higher levels of education have more respect for driving regulations. Therefore, the low level of education among the victims of road accident is considerable. 
In the present study, married people had the highest percentage of deaths, but in another study by Rakhshani, single had the highest percentage of deaths, which is inconsistent with our results [19]. Reducing fatal road accidents should be considered because most deceased were the breadwinners whose death can lead to economic issues for their families.
The highest percentage of deaths were males (69%). In this study, the death ratio of men to women was approximately 2.1. In another study by Abedini, the rate of male mortality was also higher than the other gender [9]; in two other types of research by Rahmani and Rezazadeh, the ratios were 4.1 and 3.5, respectively [12, 20]. Men are more likely to be out of the house than women, and since the self-employed had the highest mortality rate (25%) in this study, this death ratio was justifiable. In Ethiopia, the death caused by road accidents was much higher for men (82.5%) [21].
The results of the present study showed that about 45% of fatal road accidents occurred on suburban roads (43%) and only 3% of fatal road accidents occurred on rural roads. A study by Khorammi indicated that around 27% of fatal road accidents occurred on suburban roads which were 3.5 times more than fatal road accidents on rural roads [15]. In two other studies by Shahbazi and Entezami, this difference was also significant and the reason can be attributed to the high traffic on suburban roads [22, 23].
In the present study, most fatal road accidents (60%) occurred during daylight hours; our results are consistent with Khorami’s study [15]. In the present study, 24 hours of a day were divided into 4 parts. The most fatal road accidents occurred between 12 PM and 6 PM. In a study conducted in Kermanshah, the most fatal road accidents were reported from 7 AM to 7 PM [24]. This can be due to the rush to get home and take an afternoon nap. However, a study conducted in India indicated 7 PM as the time with the most fatal road accidents [18].
Nasiri’s study showed the early hours of the night as the time with the most fatal road accidents [16]. A study in Fars City, Iran, showed fatal road accidents mostly occurred between 4 AM and 6 AM that was inconsistent with our results [15].
Head and face injuries were the most common cause of death in road accidents in this study, and the other studies were consistent with the present study [15, 16, 19, 23, 25, 26]. This study showed multiple fractures as the second cause of death, but Khorami reported bleeding as the second cause of death [15].
According to the results of this study, most of the deaths occurred after transfer and at the hospital; the reason can be the small size of the city and the proximity of the scene of the accident to the hospital. Two other studies by Abedini and Rakhshani showed that most deaths occurred at the scene which was inconsistent with our results [9, 19].
According to the findings of this study, passengers and then drivers had the highest number of fatalities, while in the study carried out in Fars, Kerman, and Khuzestan drivers had the highest number of deaths [15, 16, 27].
In the present study, the collision of two cars was the highest accident pattern of fatal accidents. The results of a study in East Azerbaijan were consistent with the present study [28]. This collision can be attributed to failure to observe the safe following distance, unauthorized speed, or driver drowsiness.
In this study, motorcyclists had the greatest number of deaths. In the study by Khorami [15], motorcyclists had the highest number of deaths, while in another study by Nasiri, motorcyclists were the second group with high fatal accidents [16]. Riders are mostly at risk of injury due to imbalance caused by collision [29]. Pride and Peugeot cars have the most fatal accidents, followed by motorcycles and pedestrians. The results of other studies are consistent with our study [19, 23]. Some studies in Iran have proven some fatal accidents related to this result [30-33].
5. Conclusion
Since road accidents impose direct and indirect costs on society, intervention measures should be considered to improve public health and prevent the increasing trend of road accidents. One of the most crucial intervention measures can be the coordination between relevant officials. One of the limitations of the present study is the lack of access to all fatal accidents; hence access to registration systems should be possible in each city. Therefore, necessary measures should be taken to integrate the death registration system of the country for easy access to information.
Ethical Considerations
Compliance with ethical guidelines
This article was derived from a research project approved by Torbat Heydariyeh University of Medical Sciences (Code: IR.THUMS.REC.1397.031).
Funding
This research was supported by the research project (No.400000054), Funded by the Torbat Heydariyeh University of Medical Sciences.
Authors' contributions
Conceptualization and Supervision: Hojjat Zare; and Nayereh Kasiri; Methodology: Hojjat Zare; and Nayereh Kasiri; Mahbubeh Abdollahi; Investigation, Writing–original draft, and Writing–review & editing: All authors; Data collection: Hojjat Zare; Data analysis: Mahbubeh Abdollahi; Funding acquisition and Resources: Torbat Heydariyeh University of Medical Sciences.
Conflict of interest
The authors declared no conflict of interest. 
Acknowledgments
We thank the Vice Chancellor for Education, Research and Technology of Torbat Heydariyeh University of Medical Sciences, Student Research Committee, Forensic Medicine organization of Torbat Heydariyeh, as well as the Forensic Medicine Organization of Mashhad headed by Mr. Aria Hejazi for their cooperation and support.



References