More than 60% of accidents in Iran occur within 30 kilometers of cities entrance roads. Therefore the number of accidents per kilometer in these regions, in contrast to the other parts of roads is very considerable. The city of Tehran, as the capital of Iran, is the cross point of major arterials of passenger and freight transportation. Thus the evaluation of road safety, entering and exiting the city in the 30 kilometers buffer, can be considered to improve countrywide road safety. To investigate the effects of roadway characteristics and traffic conditions, including number of traffic violations, on accident frequency within 30 km of Tehran entrance roads, Poisson and Negative Binomial regression model were calibrated in this study. Although the goodness of fit index in Poisson model is much greater than the Negative Binomial model, the accident data dispersion in this study implies that Negative Binomial model is more appropriate to show the influences of effective variables. According to results of modeling, the variables including average daily volume, share of heavy vehicles, average daily speed violations and number of direct accesses and interchanges have effective influence on accident frequencies. Controlling access to roads and using effective actions to reduce the speed and number of speed violation can be accounted as effective policies to reduce accident frequencies within 30 km of Tehran entrance roads.

Background and Aim: Sensorineural hearing loss (SNHL) is one of the complications in hemodialysis patients. Vascular access (VA) represents a lifeline for these patients affecting their life quality and clinical outcomes. Arteriovenous fistula is the gold standard of VAs with minor complications and better hemodialysis adequacy. There is no study investigating hearing differences in hemodialysis VAs. Hence, this study aimed to compare SNHL characteristics amongst hemodialysis VAs. Methods: This cross-sectional study conducted on 64 patients aged 18− 60 years received regular hemodialysis in 2019. Demographic data and comorbid conditions were recorded based on patients’ case records and electronic databases. After a physical examination, otoscopy, tympanometry, and conventional audiometry, patients were divided into fistula (n = 26), permanent catheter (n = 36), and temporary catheter (n = 2) groups according to vascular access type. Results: Prevalence rate of SNHL was 63. 89%, 50% and 50% in the permanent catheter, fistula and temporary catheter groups, respectively. Most patients had mild sloping-SNHL in the permanent catheter and fistula groups as against moderate degree in the other group. There was no significant difference in hearing thresholds, degree and audiogram shape among VA groups. No significant relation was found between age, sex, hemodialysis duration and disease duration with hearing loss in all groups (p > 0. 05). Conclusion: More patients had SNHL in permanent catheter group. Vascular access types, longer duration of hemodialysis and disease duration do not seem to be associated with SNHL. However, further investigation is needed to clarify the relationship.