Apparently it does not take much effort to hide the fact that a median cable barrier failed to prevent an SUV crossing a median and killing 7 persons. While multiple news coverage focused on small images of the final rest position of the involved vehicles, attention was taken away from the tell-tale status of the damaged cable barrier.
These facts revolve around a tragic, multi-vehicle collision on I-85 north-east of Atlanta Georgia on Saturday, July 6, 2019. A northbound SUV reportedly crossed the median for unknown reasons and entered the southbound lanes. The resulting collision with two southbound vehicles resulted in the multiple deaths. The fact that all 4 occupants of southbound van were killed is another peculiar occurrence that needs further inquiry, but at another time. What is more revealing is how the public’s attention was diverted from the issue of the performance of the median cable barrier. Since no one was interested in documenting the poor performance of the barrier there are no photos available except some poor quality images that can be obtained from video at the site. Never-the-less, what poor quality images remain provide sufficient documenetation of the cable barrier’s failure.
The still image shown below is a frame taken from video of the site. While the focus of the video was with respect to the vehicles in the distant background, the important information lies within the red circle where we point out the status of the cable barrier.
Firstly, we can observe that the cable barrier exists only on the far side of the median, much like the situation that exists along Highway 401 between London and Tilbury, Ontario. Secondly, all the news reports simply confirmed that a Ford Excursion SUV crossed the median and nothing more. Yet, is it the purpose of the cable barrier’s existence to prevent such a cross-over? So why would news media not ask this simple question: How and why did the Ford SUV cross through the cable barrier when that should not happen? Is that not an important question when the result is that 7 innocent persons lost their lives?
The video frame below shows a closer view of the cable barrier. Note how the top cable is slack while the remaining three are tight.
Did the Ford Excursion travel over top of the cable barrier? Surely there is damage visible to the anchorage posts of the barrier in the extreme top corner of the video frame. So some contact was made with the cable barrier.
The warning signs should be raised when a similar occurrence was documented by Gorski Consulting on December 11, 2018 on Highway 401 near Merlin Road, between Windsor and Chatham, Ontario. The photo below shows the aftermath that fortunately, and miraculously, did not result in a fatality.
Again, little attention was paid to the fact that the cable barrier did not prevent the truck from passing through the barrier. A TV productrion crew was allowed onto the site to film the events for an upcoming television program. While the film crew covered the vehicle damage and the actions of the towing operators, the important matter of the barrier appeared to be of no interest.
A wider view of the Highway 401 site is shown below. Again, much like the Georgia collision site, there was a cable barrier only on the far side of the median, not on the near side.
While an investigator with the University of Western Ontario Multi-Disciplinary Accident Research Team in the 1980s, Zygmunt Gorski conducted a number of detailed documentatiuons of the travel paths of vehicles passing through the median of Highway 401 before a concrete barrier was installed. From this activity it was obvious that such travel paths and vehicle motions were chaotic and generally unpredictable when the vehicle reached the far side of the median. Even a median that is orginally designed with a well-groomed and relatively controlled slope will eventually take on uneven characteristics over the years. The belief by roadway designers that they can predict the path of a vehicle through such a median surface is clearly unrealistic. Once a vehicle reaches a barrier at the far side of the median the manner in which it strikes that barrier must be understood to be very unpredictable. And this is exemplified in the two examples shown above.What should be of concern is that, once again, little attention is being paid to these important matters that threaten the lives of innocent persons who have a right to arrive at their destinations in safety.