The complexity of a heavy truck rollover will never be properly discussed in any news media reports of trial proceedings. This is due to the fact that, in many trial proceedings, that complexity is rarely acknowledged or properly evaluated.
A trial is presently underway with respect to a fatal collision that occurred on January 6, 2021 at the intersection of Bradley Ave and Jackson Road in the south-east industrial area of London, Ontario. It has been reported that Christopher Hamilton was driving a Hydro-vac truck which rolled onto a passenger car causing the death of the car driver, 39-year-old, Sarah Jones.
Official news media covering Hamilton’s trial indicate that he was charged with dangerous driving causing death. A focus of the news media was that certain “mandatory safety forms were not filled out on the day of the collision”. While not irrelevant, this fact should have little to do with whether Hamilton’s actions were dangerous and caused Jones’ death.
Not unexpectedly, the official news media also reported that the defense lawyer, Phillip Millar, spent considerable time grilling a health and safety manager for Royal Fence Ltd., Terry Didluck, for his actions in attending the collision site. Millar suggested that the company had sent Didluck to the site to conduct his own investigation. Even if Didluck did precisely that, it can hardly be called an unexpected activity. As an employee and company-owned vehicle was involved in a fatal collision it would make complete sense that a health and safety manager of the firm would attend the collision site to get further information as to how the collision occurred.
Official news media reported the Crown’s contention that the truck had working brakes but that it had “extreme weight” and that Hamilton’s speed was too fast. The Crown Attorney was quoted as saying “He didn’t leave time or space enough to brake”. These comments and allegations cannot be evaluated without more detail. What was meant by the comment “extreme weight”? Was the truck loaded above the provincial legal requirements? That was never clarified. And the comment that Hamilton did not leave time or space enough to brake, was there evidence that Hamilton did not brake? These are very important facts that have not been explained.
The travel direction of the truck was never revealed in the news media articles. However from the evidence at the site it is clear that the truck would have been travelling southbound on Jackson Road and then was in the process of making a right turn onto westbound Bradley when the truck rolled over. Some of the characteristics of the site and remaining evidence are shown in the following photos taken on October 29, 2023.
It would also seem unusual that, upon approaching the intersection with Bradley Ave, Hamilton would not stop for the stop sign since his view to the east would be limited by trees as shown in the two photos below.
Even if he did not come to a complete stop it would seem unusual that Hamilton would travel into his right turn at any great speed since he would need to evaluate the approach of westbound vehicles on Bradley. Many turns performed by drivers of passenger cars are done at speeds of about 20 km/h and a speed of a 30 km/h would be above average. However a heavily-loaded hydro-vac truck would need to make the turn at a slower speed.
The location of the gouges in the centre of the intersection pose an unusual situation because of their location. Presumably these gouges were caused when the Hydro vac truck began to rollover. However, why is the truck rolling over so early in its right turn? In typical rollover scenarios the rollover should begin after the truck has been turned to a critical angle which would be expected to be further to the south and west.
One might conclude that the gouges in the centre of the intersection were caused by the underside of the car that was eventually pushed to the southwest and then crushed by the truck. Since there has been no indication by anyone as to the position of the car before the impact this possibility cannot be nullified. However the gouges begin north of the centre-line of Bradley and it is difficult to believe that the car would have been in the wrong (westbound) lane as the collision unfolded. So it appears more likely that these gouges are from the Hydro vac truck.
One might also argue that the gouges at the centre of the intersection were caused by another major collision. However there has been no news report of a major collision at this intersection since January, 2021. Also if the gouges we caused by another collision it would be a large coincidence that the involved vehicles could have been travelling westbound and southbound and, after impact, they would have to travel into the same area where the Hydro vac truck was found.
Thus important questions about this collision need answers but these have not been provided in any news reports of the trial.
The official news media also reported that “In an agreed statement of facts the court has heard the industrial vacuum truck was travelling too fast in the intersection when the crash occurred”. While that may be the case, the fact that these facts were agreed upon by the opposing lawyers should not leave one with reasonable assurance of reality. Lawyers are not technical analysts and what they agree upon may be totally illogical. There has been no information provided as to how the speed of the truck was determined. The simple fact that it rolled over does not necessarily mean that the speed of the truck was unreasonably selected by Hamilton.
Many modern trucks are now equipped with engine control modules (ECMs) which are capable of retaining collision data, very much like passenger cars. But even when such trucks are equipped the recording ability is often shut off by the vehicle owner/operator. Even when such a recording is available specialized hardware is required to conduct the download and such hardware is less available than a download for a passenger car. So there is strong doubt that police ever conducted a download of collision data from this truck.
Why the truck rolled over may only be partially related to its speed. The propensity for motor vehicle rollover is affected by two parameters, one being the vehicle’s track width and the other being its centre-of-gravity. The track width is the lateral distance measured from the centres of two wheels, the right front and the driver’s tires for example. The centre-of-gravity of vehicle is a vertical measurement of how high the centre of its mass is from the ground. The track width does not vary from one journey to the next, but the centre-of-gravity can change depending on the cargo being carried and this is particularly important with heavy trucks. The news media reported Hamilton’s assertion that “…he had no way to safely check the load he was carrying” and, in a roundabout way, that comment is true. He might have some idea whether his truck was carrying a load close to the maximum allowable but he has to be able to appreciate how that weight would affect whether his truck would rollover. And there is no training or data that could tell him that.
With respect to many light vehicles the track width and centre-of-gravity has been studied for many years to the point that a specific measure, the Static Stability Factor (SSF), has been developed so that light vehicles can be compared to each other for their propensity to rollover. The SSF is determined by dividing the vehicle’s track width by twice the vehicle’s centre of gravity, or SSF = t/2h. Most light duty vehicles possess a SSF somewhere between 1.00 and 1.50. The lower the value of the SSF the greater likelihood that the vehicle could rollover. Agencies such as the National Highway Transportation Safety Administration (NHTSA) have published such data to inform consumers about the safety characteristics of the vehicles they might purchase.
But what about vehicles such as Hydro vac trucks? There is no such data available. Certainly neither Mr. Hamilton nor Mr. Didluck would be aware of the SSF for the Hydro vac truck. And more importantly, the SSF value would change drastically depending on whether the truck was full or empty because the truck’s centre-of-gravity would change. But there is more.
The characteristics of the cargo being carried also has a relationship on the propensity for truck rollover. When a solid mass is carried the propensity for the load to shift can be rectified by strapping the load solidly to the truck. But when a liquid cargo is carried it cannot be strapped down and it has the propensity to slosh back and forth within the container in which it is stored. This is why for tanker trucks that carry liquids on a regular basis, baffles, or partitions, are purposely built into the tank to reduce the amount of sloshing and therefore reducing the potential for causing rollover.
But vehicles such as the Hydro vac truck do not necessarily carry liquid cargo. Sometimes the cargo may be substantially liquid and sometimes it may not, depending on what is sucked up. If the cargo on a particular day is more like a liquid it will slosh back and forth no differently than any liquid in a tanker truck. And this is where Hamilton’s comment is correct. How could he know the liquid character of the load he was carrying? He could likely know the cargo’s weight but not the percentage of its liquid form. When liquid sloshes in a holding vessel it has the effect of changing the lateral force that tips a vehicle over. Did the opposing lawyers who agreed “on the statement of facts” understand this? Unless there was an expert there to guide them it is likely that they would know nothing about this issue.
And so what about expert involvement? Will Hamilton’s trial include testimony by competent and unbiased experts who can guide the court through technical issues that they do not have the ability to determine on their own? Even when such expert opinion is available too often it is seen as an impediment to the court’s previous and obvious knowledge of who is innocent or guilty.
And here is the application of “lawn mower justice”. Lawn mower justice is where the justice system rides over top of all persons whether they are innocent or guilty. Without the public’s knowledge and intervention, the lawn mower continues to run because there is minimal accountability. The importance of catching and punishing guilty persons supersedes those instances where an innocent person’s rights are violated.
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