On the setting of retro-reflective delineators in the freeway tunnel
Xin Zhi-gan · Applied Mechanics and Materials · 2015
The paper is to introduce its study results on the approach to the rational setting problem of the retro-reflective delineators in the Freeway Tunnels. As is known,tunnels,especially,the long ones,are accident-prone places along the freeways. In order to improve the tunnel traffic safety,it is of primary necessity to provide drivers with a consist visual environment as much as close to the regular road conditions. To satisfy the demand of the alternative conditions in the tunnel,we have done an experiment by using a software name the Smart-Eye Pro 5. 7 eye tracker,we have chosen the drivers ' visual data of different combination schemes in height and diameter of the retro-reflective delineator.The experiment results indicate that,there exists a significant visual demand difference between the passenger car drivers and the large freight truck drivers towards the retro-reflective delineator setting height. For example,it would be optimistic to set the retro-reflective delineator setting height about 0. 4 m for the small car drivers; and accordingly,the best setting height for the drivers of large or heavier trucks has been proved about 1. 0 m. In order to control the flash frequency intensity which influences the drivers' visual perception,we have discovered that 15 m should be taken as the proper spacing between the delineators. Or more practically speaking,to meet the drivers' visual demand,the rate of drivers' pupil diameter change should be controlled within the range of 0. 396-1. 302 mm / s. In accordance with the said demand,the best suitable delineator materials for the reflective grade for small cars should be of ultrastrong grade,whereas it belongs to the general engineering-level for the huge trucks. One more point to be added is that the research results of this paper have already been adopted to Muchong Tunnel of G65 freeway in Guangxi Zhuangzu Autonomous Region with a result being that the rate of the drivers' pupil diameter change has been controlled inside 1. 302 mm / s,and,in turn,the accident frequency has been reduced by 51. 8% as against the same period of the last year.