The Impact of Heavy Vehicles on Freeway Safety (Case study: Qazvin-Zanjan Freeway)

Heavy vehicles are an important part of the country's transportation system, which, due to their physical and functional conditions, have an impact on the safety conditions of roads, especially freeways, which account for about 15% of Iran's road accidents every year. In this research, the Qazvin-Zanjan freeway has been chosen as the axis of study because it is considered a transportation and transit axis and the volume of truck traffic is high, and the required information regarding truck accidents on this freeway, related to the years 2012 to 2014, It has been collected from the General Directorate of Highways and Road Transport of Zanjan province. This research, in two descriptive and inferential parts, examined the frequency of accidents and tested the data through the chi-square test with SPSS statistical software, and it was determined that factors such as clear weather, lack of lighting on the road, and the traffic of 2- and 3-axle trucks in the frequency of accidents in the studied axis They are effective. Considering the necessary measures and suggested amendments in the existing laws, the number of these types of accidents can be reduced in a short period of time.