The purpose for the installation of a guardrail and its terminal is so that it will prevent impacts with dangerous objects such as the struck tree in the background.

Once again an ET-Plus terminal manufactured by Trinity Highway Products of Dallas Texas has demonstrated its questionable safety performance. Yesterday morning, Tuesday, November 6, 2018 police reported that a  car was westbound on Calvert Drive, south-west of Strathroy, Ontario. The female driver lost control of her car. The car crossed on the the south roadside where it reportedly hit a “guardrail” and then struck a tree. The female driver sustained life-threatening injuries. Given that guardrails are supposed to prevent impacts such as trees we decided to investigate. Furthermore, given the imprecision of descriptions by news media I was suspicious whether a guardrail was struck or whether the terminal of the guardrail was the actual point of impact.

I attended the collision site this afternoon, November 7th. My suspicions were confirmed, as shown in the above photo, that it was indeed the terminal of the guardrail that was struck and not the guardrail itself. Furthermore, the terminal was an ET-Plus which has had a considerable history controversy surrounding its performance. This continues to be my experience from examining a number of impacts over the past 4 years. There continue to be incidents of jamming of the terminal on the rail and thus preventing it from dissipating the collision energy in the manner it was designed to do.

In this latest incident the guardrail became jammed within the channel of the terminal, like it has done in a number of previous incidents I have examined. The photo below shows what happened in the present case as the ET-Plus terminal rotated past 90 degrees and thus made it impossible for the rail to pass through its throat. Only a very small length of the rail can be seen extruded from the throat of the terminal and this occurred before the system became jammed.

This metal rail is supposed to be squeezed through the throat of the terminal and come out in a flattened and curled shape. This is the process by which the kinetic energy of the striking vehicle is dissipated. Instead terminal has rotated to beyond 90 degrees with respect to the length of the rail and it became impossible for the rail to pass through the terminal.

If the terminal had performed properly a substantial amount of kinetic energy possessed by the vehicle would have been dissipated and thus the speed of the vehicle would have been reduced. Thus even if the car passed through the barrier the severity of the impact with the tree would have been lessened. The extent of damage to the tree can be seen the photo below.

Judging by the extent of damage visible at the tree, the female driver’s injuries were likely caused from this impact, more so than from impacting the ET-Plus terminal.Overall there continues to be evidence of questionable impact performance of ET-Plus terminals.