| In recent years,the semi-trailer train（hereinafter referred to as semi-trailer）played an increasingly important role in the highway freight transportation.It was urgent to study the formation mechanism of blind areas during semi-trailer right-turning and early-warning prevention measures to ensure traffic safety.Because the rate of collisions with slow-traffic travelers caused by semi-trailer right-turning blind area had risen sharply,and the high fatality rate had seriously threatened the life and property safety of travelers.Based on the statistical investigation of related collision accidents and the characteristics analysis of semi-trailer right-turning and slow-traffic travelers,this paper explored the formation process and interactive relationship of the blind area of trajectory and the blind area of right rearview mirror combined with the actual vehicle test.Using PC-CRASH software,simulation model of the collision between semi-trailer and slow-traffic traveler was established,and studied the influence of different factors on the collision results and damage degree.Finally,the prevention and treatment measures for blind areas warning were proposed.The main research contents and findings can be summarized as the following aspects.（1）The formation process and interactive relationship of the blind area of trajectory and the blind area of right rearview mirror.The inner wheel difference model during semi-trailer right-turning was established by introducing virtual axis,and the method of determining the minimum safety distance for semi-trailer right-turning is discussed.Combined with the actual vehicle test,the relationship model of right rearview mirror visual vehicle length and semi-trailer turning angle in the right-turning process was established.Furthermore,the interaction mechanism of double-blind areas was analyzed.The results showed that the size of the included angle between tractor and trailer significantly affects the interaction and degree of the double-blind areas.When the included angle is 28.8°,the blind area of the rear-view mirror begins to generate,and as the included angle increases,the double-blind areas.begin to interact.When the angle is increased to63.4°,the double-blind areas produced by right-turning is the largest.It is determined that the minimum safe distance when a semi-trailer turns right is 4.4 m.（2）Safety evaluation indexes of collision accident between semi-trailer turning right and slow-traffic travelers.Using PC-CRASH software,simulation model of the collision between semi-trailer and slow-traffic traveler was established and the influences of collision position,driving speed and turning radius on the formation process of blind area of right-turning trajectory,human body injury and visual vehicle length were analyzed.The results showed that the front 2L/5 range of semi-trailer was the most dangerous collision area with a risk index of 0.7.It was suggested that the right-turning speed of semi-trailer should not exceed 25 km/h,and the minimum turning radius should be controlled at 9.0 m≤r1≤10.5 m,r2≤15 m.（3）The blind areas warning and prevention measures of semi-trailer right turning.Based on the formation of the blind area of right rearview mirror,the minimum angle of the supplementary right rear-view mirror when the semi-trailer turns right was calculated to be41°.The right-turning visual observation and blind-filling measures combined the traditional rearview mirror with the camera device was proposed.At the same time,the prevention and treatment measures such as the projection warning system of the inner wheel difference blind area and the mark and marking of the right-turning area at the intersection of the road were proposed.These can effectively reduce the blind area of the rear-view mirror and the accident rate. |
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