According to the Global status report on road safety 2018, 1.35 million people worldwide die each year due to traffic accidents, and traffic accidents are the eighth leading cause of death for all ages. Also, the mortality rate dealing with traffic accidents in low-income countries (27.5 percent of people) is 3 times higher than in high-income countries (8.3 percent of people), which shows the high importance of traffic accidents, especially in low-income countries (12). The results of the present study showed that the mortality rate dealing with traffic accidents in Iran during the years 2006 to 2018 had a decreasing trend. However, based on these results, the average age of the deceased has increased during the study years. According to the WHO, the number of traffic accidents deaths decreased slightly from 18.8 percent to 18.2 percent, from 2000 to 2016 (12). In this regard, the results of the study by Sadeghi-Bazargani et al., conducted in East Azerbaijan province among bus and minibus users during 12 years (13), and Mahdian’s study conducted in Kashan (14), showed the decreasing trend of fatal accidents in Iran. Also, the results of a study performed in Colombia showed that the incidence of traffic accidents deaths from 1998 to 2012, in people under 60 and over 60, has a decreasing trend (15). The results of a study by Fernandes et al showed that the incidence of traffic accidents across pedestrian in Brazil decreased from 1996 to 2015 (16). In our study, the results for vulnerable road users (pedestrians, cyclists and motorcyclists) were not available for further investigation, however, the study of Hamzeh et al., conducted in Kermanshah showed that there was a declining trend in the number of traffic accidents deaths in pedestrians from 2004 to 2013, while the number of the deaths among other vulnerable road users fluctuated during these years (17). In general, the declining trend can be partly due to the separation of type 2 traffic accidents and non-traffic accidents (since 2013) from traffic accidents which can have a significant impact on reducing the trend of the mortality, and likely more to some reasons such as reforming traffic laws and imposing heavy fines on offending drivers, especially in cities, installing more surveillance cameras on roads and in cities, and emphasizing the use of helmets (15, 17). It seems that the existing differences between the provinces of the country in terms of traffic accidents deaths and its trend over the years are affected by the economic situation of the provinces, although this issue needs further investigation. However, in this regard, studies have shown that the amount and trend of the reduction in traffic accidents deaths in different countries are different and has a strong relationship with the economic level of the countries so that the risk of traffic accidents death in low-income countries is 3 times higher than high-income countries (12). The results of a study conducted in Brazil showed that the reduction in the incidence of pedestrian deaths in the northern regions of Brazil has been slower than in other regions. Results of the study showed that one of the reasons for this difference is the worse economic situation in the northern regions of Brazil than in other areas (16). This difference can be due to having more facilities and financial support for designing safe and preventive interventions at different levels and different tools in areas with better economic status. According to the results of this study, the highest mortality rate was observed in the age group of 65 years and above, although this rate has been decreasing during the study years. These results are similar to the results of studies reported in Iran (14, 18, 19) and Colombia (15). A significant proportion of older people suffer from hearing loss, visual impairment, cognitive decline, musculoskeletal problems, imbalance and gait, and a variety of chronic diseases, which puts them at greater risk for road accidents, injuries and subsequent deaths (15, 19). Since a significant proportion of traffic accidents deaths are likely to occur in people over 60 years of age due to urban accidents and pedestrians, street crossings should be installed or adapted for this age group. Installing escalators or elevators in the area of pedestrian bridges can be such measures.