As part of the programme to develop safer street lighting columns for use on high speed roads a test has been carried out on a tubular steel column 40 ft high fitted with a shear joint at ground level. To simulate the case when a car runs off the carriageway on a high speed road, a medium sized saloon car was remotely steered into the column at a speed of approximately 60 mile/h. The main findings are listed below. (1) The declaration of the colliding car was so slight (an average of 2.2 g for 0.05 seconds) that it is unlikely that occupants would have been seriously injured. (2) The bottom of the column shaft was pushed away so that the car passed under it. (3) The column fell behind the car. Had this been a real accident it would either have fallen completely clear of the carriageway or have encroached only slightly into it, depending on the angle at which the car was leaving the road and the initial position of the column relative to the carriageway. It is concluded that the incorporation of a shear joint of the type tested into tall tubular or other steel lighting columns of normal height would greatly reduce the severity of injuries to the occupants of high speed motor vehicles colliding with the columns. (Author/publisher)
Abstract