Highway 407 Tanker Truck Fire – Dashcam Analysis
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.
Highway 401 – Median Barriers, Construction & Other Complaints Are Studied
What decisions do drivers make when their lane is ending and they are traveling at highway speed? Gorski Consulting has conducted testing with traffic cameras on Highway 401 to find out.
At highway speeds, with high traffic densities and a sudden emergency, drivers need to make quick decisions that could cost them, or drivers around them, their lives. Decades of research has helped to create the roadway environments that reduce the need to make those sudden decisions. Yet, unexpected events can occur.
Highway 401 in southern Ontario has received its share of complaints. From Windsor to Montreal this super-highway carries the highest numbers of Canadian drivers, by far, than any other. Its character changes greatly whether it contains multiple express and collector lanes in Toronto, or whether it contains only two lanes without a median in areas east of Kingston or close to Chatham.
Construction, maintenance and policing activities become a problem when traffic volumes increase. Often lanes become closed for these activities and drivers must make adjustments in their speed and lane travel. Numerous collisions occur in construction zones when closed lanes cause drivers to change lanes or bring traffic to a halt. Many collisions occur when unsuspecting drivers approach the stopped traffic at highway speed but are too late in their detection that traffic is stopped. This is more problematic when heavy trucks are loaded with cargo but their braking systems make if difficult to stop as quickly as passenger cars and light trucks. Numerous problems like these require objective data in order to develop counter-measures that provide realistic solutions to the problem.
Recently Gorski Consulting has been conducting observations along Highway 401 to gather the objective data that may form the grounds for improvements in the future. The use of synchronized, multiple, video cameras, placed in a short-range environment, allow for data to be collected about driving patterns and drivers’ actions.
The most recent observations were conducted on October 30, 2018 on Highway 401 near the Westminster Driver overpass on the outskirts of London, Ontario. This location has moderate traffic volumes that allow a relatively free flow. Considerable construction activities are currently taking place between Chatham and London however, at the time of the observations, no such construction activity existed in the vicinity.
The typical procedure is to paint markers at 100 metre intervals along the road edge. A video camera is pointed at the marker and it documents when vehicles pass that reference point. At the next 100 metre location another video camera captures the same vehicle. By knowing the time interval that it takes a vehicle to pass between the two markers an average speed is obtained. Other information such as the following distance of one vehicle behind another is also obtained.
Video cameras placed along the side of the highway document vehicles as they pass by paint markers and traffic cones placed at 100 metre intervals. This method provides information about the average speed of the vehicles.
The Westminster Drive site is particularly useful because the westbound lanes of Highway 401 become reduced from 3 lanes to just 2. This produces observations of drivers who must change lanes. Information about how long drivers wait to change lanes before reaching the end of the lane can be useful as failures in this decision making can be the source of collisions. Information is also obtained about how other drivers react to a vehicle attempting to cross into their lane and if they are accommodating and helpful or otherwise.
Panoramic views along the highway are also taken from the Westminster Drive overpass with cameras pointing east and west. This provides an additional perspective of the traffic.
View of two video cameras positioned on top of the Westminster Drive overpass and pointing at traffic east and west of the location.
Decisions regarding when to make a lane change are still far away from being completed by self-driving vehicles. While an algorithm developed through substantial research may provide the correct response in high percentages of instances, there are still situations where a human driver may be able to foresee something that the computer cannot, thus requiring human control to change the vehicle’s motion.
In this view the driver of the red car has succeeded crossing out of the ending lane at the very last instance. Decisions such as these can be problematic when traffic volumes are high and opportunities to make that lane change are limited.
The study of human decisions and how they drive can be beneficial to the creators of self-driving vehicles because, even if self-driving cars fully populate the road system there will still be a long ramp up process when self-driving cars will need to live among human decision makers.
Farm Tractor Lighting – Not Enough, Too Much or Too Confusing
Farm tractor lighting can lead to collisions when drivers do not understand their difference from typical motor vehicles.
When approaching a farm tractor from the rear drivers often assume that the lighting and its meaning is predictable much like city traffic. There are differences that could prove deadly. The lighting on the tractor in this photo is partially obscured making it appear that the vehicle will be making a right turn.
Farm tractors, much like construction equipment, often contain extra, flashing, lights that are located at portions of the vehicle that are not common. Drivers from urban areas who are not familiar with approaching such vehicles can obtain the wrong information about what the lights mean. Many farm vehicles are equipped with flashing amber lights that appear to be the same as the turn signal lights of urban vehicles. When a full view of the lighting is not observed a driver may believe the farm vehicle will be travelling straight ahead or making a right turn and attempt to pass. At the last moment the opposite may be true.
Because the left turn signal is obscured an approaching driver might begin to pass the tractor without knowing that the tractor is preparing to make a left turn.
This is something to think about next time you approach farm vehicles.
OPP Speed Enforcement on Hwy 401 – Actual Observations Indicate Greater Problem
View of Highway 401 near Elgin Road (Highway 73) in Middlesex County where an observational study was conducted to estimate the average speed of vehicles travelling in the median (fast) lane.
The OPP reportedly conducted a two-day “aerial blitz” of speeding vehicles along Highway 401 last week. The number of charges are far below the actual number of speeders that could have been ticketed. It was reported that 72 charges were laid, 38 of which were for speeding. Observations of the speed of drivers conducted by Gorski Consulting indicate that this must have been a very short or very selective enforcement because of the actual number of speeding drivers that actually exist.
In the Gorski Consulting study conducted in November of 2016, near the interchange of Highway 73 east of London, Ontario, westbound traffic was documented with multiple video cameras for slightly less that 8 minutes. In that time 62 vehicles were observed travelling along the fast lane, or the lane closest to the median. Twenty-four, or 39%, of those vehicles were observed to be travelling over 120 km/h. Matching this data to the 38 speeding charges by the OPP, and assuming the location of their blitz was at a similar traffic volume, it would suggest that the OPP observed less than 15 minutes worth of traffic during the blitz. The OPP were quoted as saying this blitz was “designed to increase public compliance with safe driving measures”. This may help to publicize the extent of the problem but the blitz itself is unlikely to have had any effect on the speeding habits of drivers.
The difference in the numbers of observed speeders and what charges were laid outlines an obvious problem about the lack of enforcement of speed limits along Highway 401. The reality is that pulling vehicles over for a speeding violation along the Highway is a dangerous operation that could produce more harm because of the potential collisions that it can cause. While a “move over” law requires drivers to slow down and change lanes away from emergency vehicles the reality is that such changes in speed and direction are themselves the cause of collisions. In many instances speeding drivers cannot change lanes quickly enough because of factors such as visibility problems and traffic density. The sudden reduction in speed of vehicles causes speeding drivers to brake suddenly and cause problems for other speeding drivers around them. While it can be said that this is the fault of those speeders it never-the-less does not prevent the causation of serious consequences.
The other reality is that there is likely not enough police available to deal with the speeding problem. Enforcement could reduce the speed of vehicles over an extended time when drivers begin to recognize that police are monitoring drivers’ speeds on a regular basis. But this takes manpower that our society is presently unwilling to pay for.
Under these difficult realities technological advances such as the implementation of automatic emergency braking cannot come fast enough, particularly for heavy trucks and buses. While this may not be a panacea in itself, early findings indicate it could make a large difference in the types and severity of collisions that occur on high-speed freeways like Highway 401.
Extreme Case of Bumper Over-Ride Highlights A Common Safety Issue
Sometimes eye-catching photos of extreme bumper over-ride can draw the public’s attention to more meaningful consequences.
An extreme case of bumper over-ride was published on the OPP’s West Region twitter account today. The front end of a tall pick-up truck was shown on top of the hood and windshield of a small passenger car and the incident reportedly occurred in the area of Norfolk County, Ontario. OPP reported no one was injured from the incident and that is good news. More importantly these views may have caught the attention of many persons who would ordinarily be too busy with seemingly more important matters in their lives – until they are caught up in a major collision that threatens them.
While the view of one vehicle on top of another appears dramatic, a closer analysis reveals a relatively, low severity event. But it raises awareness to other issues.
Views from this present incident indicate that it was more eye-catching than life-threatening. There is minimal crush visible on both vehicles. Even the interior of the car shows minimal potential for intrusion into the driver’s space and the air bag did not deploy. That is the goods news. But this scenario outlines much more serious concerns.
Even though the left front wheel of the pick-up truck is partly onto the car’s windshield there was minimal structural intrusion into the driver’s space and the air bag did not deploy.
Even a quick glance at my reference library shows a copy of a Society of Automotive Engineers (SAE) manual from 2005 entitled “Vehicle Aggressivity and Compatibility in Automotive Crashes”. This is a compendium of research papers related to collisions similar to what is shown in the above photographs. Even early in my career, in the 1980s while I was conducting investigations of over 100 major collisions a year, I had developed a theory from studying the results of hundreds of head-on collisions including a specific study of Light Truck and Van (LTV) collisions that was conducted over a period of over 3 years. The theory I developed was that, if one wanted to survive a major head-on impact at relatively low cost, one should buy a four-wheel-drive, Chevrolet Suburban. The Suburban was stiff, it had a wide stance and its bumper was taller than most passenger cars. My studies demonstrated that, in a head-on impact, the vehicle that rode over top of the other vehicle’s front end resulted in a better chance of survival for the over-riding driver. That observation was true in many ways for many years.
Not long after the owners of pick-up trucks began placing lifters on their suspensions and the bodies of their trucks began to rise higher. Even manufacturers began building light trucks with higher suspensions. It can be seen of the Chevrolet Silverado in the above example that its body is well above the typical height of an old-style truck of the 1980s. The advantage of a higher body was often seen in Jeeps which also had a stiff bumper/frame that was higher than typical passenger cars. The drawback of Jeeps however was that they had a smaller wheelbase and track width than a Suburban and were more prone to instability, particularly after the initial head-on impact. And this leads to another issue regarding survivability, height and instability that few would expect.
As I originally observed “height wins”, But not in all facets. Height wins during the initial 110 milli-seconds as two vehicles reach they point of maximum engagement (maximum crush) and the stiff bumper area of the taller vehicle drives through the softer upper regions (hood, fenders, etc) of the vehicle beneath. But often the vehicle collision does not end there. In most instances a head-on collision involves 60 percent or less of a vehicle’s front end. This means the vehicles’ centre-of-gravity do not line up and that the collision is not “central” but is off-set. This means that, although much of a vehicle’s velocity could be lost in the initial impact, the vehicle may also have additional, residual velocity after the initial impact. This is more true of taller vehicles because they are also likely to be more massive and they are less likely to be stopped by the lower, less-massive, collision partner. The bottom line is that this taller vehicle which rides over the top of the lower vehicle now becomes destabilized. That destabilization often involves the lifting of only the struck half of the vehicle such that, upon leaving the area of impact this taller vehicle has a greater tendency to begin to rollover rather than slide on its wheels to final rest.
So, having survived the initial impact because of the vehicle’s superior body height and mass, this driver is now faced with a possible substantial, post-impact velocity while commencing a rollover. This may not sound threatening because we know that, as long as the driver is properly restrained in a seat-belt, and stays within the safe confines of his/her vehicle, the deceleration rate of about 0.5 g will be of minimal consequence. But that is not the only issue.
In a major head-on impact there is a higher probability that the direct contact damage and crush is to the left front and thus a varying amount of deformation can occur which can exist as far back as the driver’s door without producing any serious structural intrusion. Meanwhile, near the end of this same impact, after the air bag starts to deflate and the driver is out of position, the relationship between the restraint system may not be ideal and the various components such as the door, side window or window sill may not be of the same shape as it was pre-crash. There is no guarantee therefore that a driver will stay comfortably confined by the restrain system, in a properly seated position, while the vehicle goes through a post-impact rollover with a substantial post-impact velocity. Partial ejection of the upper torso and head during these occasions have resulted in deadly consequences.
Too often the public has seen TV commercials demonstrating how a vehicle occupant is ejected clearly out of their vehicle and sustained their fatal injuries from striking the exterior environment. While this is one mechanism by which fatal injuries occur it is by no means the only mechanism. Whether it is full ejection or just partial ejection the body of the ejected occupant is in the vicinity of the vehicle when that vehicle is rolling over. The result is that the rolling vehicle may actually crush the ejected occupant’s body several times during the rollover before both come to their rest positions. Thus the lucky driver whose taller and heavier vehicle allows he/her to survive an initial impact may sustain fatal injuries from the seemingly less dangerous post-impact motion to rest.
Another important issue that is illustrated by the above photographs is air bag deployment. Note that the air bag in the small passenger car in the above photos did not deploy. Certainly this could be for a reasonable and foreseen eventuality programmed in the algorithm of the air bag control module. But one really knows. The triggering of air bags and the algorithms of how that is done is considered proprietary information that is only available to the manufacturer. I belong to several internet chat group of over 1000 international reconstructionists and there are many occasions where such investigators pose the question: ” Should the air bag have deployed in this described case?” or conversely “Should the air bag have not deployed considering the the low severity of this described case?” While a number of experts are willing to propose various reasoning for why the deployment should nor should not occur, the reality is that, without the details of the decision-making continued in the control module, it is only conjecture.
When vehicles of very different heights come into a head-on collision it becomes problematic, not only for the manufacturers to detect when an certain scenario requires air bag deployment, but investigators outside of the manufacturers also have a greater difficulty in making a correct determination of what should have happened. The reality is that the decision to deploy an air bag has to be made in a very short of time of 25 to 50 milli-seconds and that is well before there is enough information to know how the complete collision will eventually unfold. Much of the decision-making is made about the rate at which the velocity is changing. In fact the decision is made partly on the rate at which the acceleration is changing, which is referred to as Jerk. But no one can be sure what additional factors are taken into account or how. So the above photos help to bring attention to this fact that vehicles of different heights cause problems when they collide because the sensors that are positioned to capture the typical collision may not sense a collision in sufficient time to make a proper decision about air bag deployment.
In the end it does not create much harm when the OPP place photos on their Twitter account of a seemingly harmless and meaningless collision that catches the public’s attention. It gives me the opportunity to catch the public’s attention and discuss some consequences that could be major factors in their lives or of those near to them.
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