Two obvious issues needed to addressed from yesterday’s explosive fire that erupted when a tanker truck crossed over a concrete median barrier on Highway 407 between Keele and Dufferin Streets on the outskirts of Toronto, Ontario. A driver’s dashcam captured the seconds before the tanker truck impacted the barrier and this can be used to evaluate some of the concerns.
Firstly, the dashcam view shows that the westbound tanker truck was in one of the far right lanes when it was observed to travel across the highway. Markings on the barrier indicated the existence of black transfers that could suggest the scrubbing of tires (as is common) and there appeared to be a light-coloured area on the barrier that would be typical of metal contact. Photos of fire-fighters standing near the barrier provide some clues as to its height. A standard Ontario High Wall barrier would be about 110 centimetres (42 inches) tall. A typical male would be about 178 centiemetres tall. The photos suggest that the top of barrier could be slightly more than half the height of the firemen – but that remains to be seen. Certainly, one of the first questions to be asked should be “How tall was the barrier and was it of standard dimensions?” Standard dimensions are important because, although many concrete barriers are referred to as “Jersey” barriers, there could be some dimensional differences that may be important in preventing traffic from riding too high onto the barrier wall.
Secondly, the dashcam view showed how quickly the fire erupted just after it rolled onto the other (eastbound) side of the barrier. That sudden eruption should not occur. Typical tanker trucks that carry explosive fuel are designed to higher levels of safety to prevent rupture and explosion. So the next question that should be asked is “Why did this fire commence so quickly and was there a relationship between the design of the truck and the design of the barrier?”
Thirdly, the dashcam view would appear to confirm the obvious that the tanker truck rolled over the barrier. That is not what we would want to occur and that is why we have a tall concrete barrier to prevent that from happening. I have expressed previous concerns regarding the heights of roadside barriers and the incompatible centre-of-gravity heights of typical, heavy trucks and buses. Almost all roadside guardrails and barriers are too low to prevent a heavy truck or bus from rolling over the barrier. In fact, in many instances the low barriers actually “trip” the heavy vehicle into a rollover which might be less severe if the barrier was not present and the heavy vehicle was allowed to track or slide on its wheels to final rest.
We require the presence of roadside barriers and guardrails because they are generally successful in re-directing or slowing the motion of passenger cars and light trucks. However there is never any discussion about the dangers posed to heavy trucks and buses. The tanker truck in the present case likely had a high centre-of-gravity and that issue needs to be publicly addressed. Again, with no obvious solution many transportation officials and engineers would rather not talk about this problem. That is not always the best way to resolve a problem.
We also need to examine what was the cause of the tanker truck’s initial motion out of its lane on the far right side of the highway. Just yesterday I posted a news item on this website discussing the multi-video camera documentation of Highway 401 traffic on the western outskirts of London, Ontario. That analysis documented how vehicles changed lanes at a location where one of the 3 lanes terminated. Thus we could explore the conflicts that can occur resulting in drivers taking evasive actions to avoid a collision. Was the tanker truck’s motion in the present collision representative of some type of traffic conflict that occurred in, or next to, the truck’s travel lane? This is another question that needs to be publicly answered. The type of independent, non-funded, research being conducted by Gorski Consulting can provide insight into how such collisions occur. We will be posting some results of our Highway 401 observations in the near future.
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