The effect of roadside elements on drivers' speed selection and lateral position on road

Highway related crashes are considered as one of most concerned types of problems in the modern world. Run-Off-Road (ROR) crashes could be identified as the most critical among highway related crashes. Previous research studies on Traffic Engineering has found that the road side elements will have a positive influence toward ROR crashes. Hence, the study explores the relationship of roadside elements with drivers' speed selection and lateral position. In this research study, the effect of road side vegetation and utility poles on drivers' speed selection and lateral positioning was evaluated. A straight roadway section and horizontal curve roadway section with varying road side vegetation were selected to get the required data for the study. Fifty vehicle were observed at each location to get the speeds and lateral positions. Collected data was analyzed using Multiple Regression Analysis technique to generate models to find drivers' speed selection and lateral positioning of vehicle on road. Study found that in lightly vegetated roadways, subjects drove speedier and drove much near the edge of the road. At the point when the scene changes into more vegetated, subjects drove much slower and drove near to the center of the road. The models demonstrate that the impact of road side vegetation way much higher in curved roads areas than straight segments. Therefore, it is recommended to post a speed limit sign and proper monitoring system at each critical curved roadway section in the country.