Application of Global Positioning System Data for Automatic Control of Safety Standards Related to Speed Signs before Horizontal Curves

摘要

To secure safe conditions for road transportation is of great importance and calls for high cost to control the unrestrained trend of road accidents. The use of Mobile Mapping System as a method for road safety auditing, is a trend that provides a comprehensive database of information including video images and geographical information. In this paper, the data collected by the Global Positioning System reciever installed on the Mobile Mapping vehicle is taken into consideration. The goal of the present paper is to introduce an automatic method which can control the safety standards related to speed limit signposts before the horizontal curve and maintain sufficient accuracy in controlling the safety standards related to warning signs before the horizontal curves and also analyze the coordinates of the centerline axis points of the path and determine the geometrical specifications of the horizontal curves to economize on time and cost. The proposed method is capable of presenting a safety distance before the beginning of the curve for the purpose of installing suitable signpost to reduce the speed and automatically control the safety standards related to them. On the basis of the obtained results, in 174 identified curves on 318 kilometers of an undivided two-lane rural road, the accuracy of the proposed method for sharp horizontal curves (radius of less than 150 meters) was proved to be 90% for the phase of determining the horizontal curve radius and it was 97% for the phase of determining the beginning point of the horizontal curve.