Investigation of the Driver's Eye Height from the Ground According to Variation in National Transportation System Characteristics

One of the significant issues in the road safety is sight distance. Rules and parameters for stopping sight distances in Iranian driving law often refer to values found in AASHTO reference well consolidated that these values are related to the United States’ studies during the years 1938 and 1941, and the driver’s eye height from the ground is one of these parameters. While the world periodically monitors variations of this parameter, in Iran the value has remained unchanged for some fifteen years, despite changes to the technical characteristics of the national vehicular fleet and the driver population. The aim of this paper is to submit recent surveys from a significant percentage of passenger cars and to determine the statistical parameters for the set of measured values, and also localize and update the value of this parameter based on driver behavior in accordance with the existing fleet. In this research, 198 values of driver eye height were obtained from a cross picture of travelling cars in the cities of Tehran, Mashhad and Semnan. The results showed that the level of Iranian driver eye height is higher than the value given in the Iranian driving law. This height is one of the parameters needed to determine the minimum radius in the vertical crest.