The results of capital stock and labor force coefficients showed that there is a constant return to scale in the road transport fleet sector. Also, in this sector, new investment and renovation has increased with technical progress in such a way that it has reduced the average age of the fleet and has led to an increase in the growth rate of qualitative capital and productivity. So; The direct relationship between fleet renewal and productivity in Iran's road transport sector is confirmed. Therefore, it is suggested to use equipment with superior technology and replace the road fleet with new and advanced equipment Therefore, all parts of the road transport industry require their own special attention, which is addressed to each of the topics in the discussions related to road safety management; And its special rules, regulations and standards should be taken into consideration. The road transport fleet is considered as one of the most strategic transport systems of any country. High level and technological complexity, quality and strict prerequisite standards have made this system known as one of the most effective transportation systems in the world.