A bus crash near Smoky Lake Alberta this week brings back memories of the Humboldt Broncos crash. Looking at the two crash site photos (above) there is an eerie similarity with respect to the final rest positions of the vehicles. In the Smoky Lake case a smaller truck collided with a school carrying 14 students. Critical injuries were reported to some students but little further information has been provided.
A major difference between the Smoky Lake collision and the Humboldt Broncos tragedy is that the school bus was struck in the right side. In contrast the Humboldt Broncos bus struck the side a large, loaded trailer of a Tractor-trailer combination. The side of any vehicle provides less protection to its occupants for obvious reasons as there is less structure available to protect the occupants from the impact force and structural intrusion. Thus, on face value, one should expect that the occupants would be more vulnerable to injury in this school bus than in the Humboldt Broncos crash. Yet, although the severity of injuries has not be fully established, substantially more injury, and death occurred in the Humboldt Broncos crash.
Few have been willing to highlight the obvious fact that very little of substance has been released with respect to how the occupants of the Humboldt Broncos bus sustained their injuries. The RCMP, which was the only official agency allowed on the site, and was the only agency that could document crucial facts about the crash, have never released their report for public evaluation. Without such details there are critical concerns about what has been reported and this can be contrasted with what is visible in the travel paths and rest positions of the vehicles in both collisions.
For example a momentum analysis is frequently used in collision reconstruction to establish the pre-impact speed of vehicles. Such an analysis uses some of the following details taken from the post-impact status of the evidence.
- The pre-impact travel directions of the vehicles.
- The mass of the vehicles
- The post-impact travel angle of the vehicles
- The post-impact travel distance of the vehicles
Using such data a momentum analysis is a “closed box” such that, based on the above assumptions, an exact value of the pre-impact speeds and collision severity will be the resultant output. Opposing analysts argue about the assumptions being placed in this closed box because, once those assumptions are accepted the momentum results are straightforward. However, when the details that are necessary to complete a momentum analysis are not provided, such as the case in the Humboldt Broncos matter, the validity of a momentum analysis, or any analysis of pre-impact speed, can be in dispute. So, without those details, only very broad observations can be made. And when no further information is available the only understanding that can be obtained is through blind faith that those providing the conclusions have, in fact, performed their analysis in a crediable, valid manner.
Here is one of the general observations that can be made from both collision sites. The angle of departure of the vehicles in both crashes is similar. For simplicity, if we assumed that the masses of the vehicles in both crashes were similar in proportion to each other then the only factor that would cause these similar departure angles is the speed of the vehicles coming into impact. We have been told that, in the Broncos crash the loaded truck failed to stop at a stop sign and was reportedly travelling at highway speed at the time of impact. Similarly, the Broncos bus was also travelling at highway speed at the time of impact. Thus we should expect to see a departure angle of both vehicles in the range of about 45 degrees, and this is generally what is shown in the photo of the accident site above.
However the 45 degree angle of departure in the school bus crash at Smoky Lake is also visible in the collision site photo (above). Yet police reported that the school bus driver had stopped at the stop sign and then pulled out before the school bus was struck in its right side. So how could that make sense? If the truck was travelling at highway speed and the angle of departure was about 45 degrees, then the school bus must also have been travelling at highway speed. Yet how could the school bus be travelling at highway speed when it has just pulled out from a stopped position at the stop sign?
One of the ways reconstructionists settle these discrepancies is by also considering the energy that was dissipated in the crash. So if both vehicles are travelling very quickly we should see a lot more crush in the structures of the vehicles than if both vehicles are travelling slowly. Once again, without any details except what we can see in the site photos, this energy analysis must be very broad. It has been observed that a number of persons came to the conclusion that the roof of the Broncos bus was detached as a result of the collision and therefore it should be not surprising that fatalities occurred. However this detachment is very suspicious as there is no explanation why the roof pillars would be “cut” in the manner they appear to be. Conversely it is well known that emergency personnel will cut off a roof, especially when there are many injured occupants. Thus this roof detachment is likely not related to the severity of the collision and is likely a red herring that is confusing the public. The principal crush was at the front end of the Broncos bus and therefore it would be prudent to inquire if any occupants sustained major injuries when they were located a substantial distance, within the bus, from that crush. It is well understood that when a long vehicle is involved, and occupants are located far from the point of crush, the severity of a collision experienced by those distant occupants is different than the severity experienced by the occupants close to the area of crush. It is unlikely that all the fatally injured and critically injured occupants of the Humboldt Broncos bus were located at the very front where all the crush took place. So this issue needs proper study.
Finally, we can look at the travel distances of the vehicles after the impact. In general, when we look at the combined travel distances of both vehicles, the vehicles that are travelling at a faster speed before impact will also travel a longer distance after impact. Yes, that is a very bold simplification because that is not always true, but without the availability of the precise evidence, we can make that broad observation. Looking at the travel distances shown in the two sites, if anything, it would appear as if the two vehicles in the Humboldt Broncos crash travelled a shorter distance than the two vehicles in the Smoky Lake crash. On this basis it should cause us to ponder why this is so. Certainly factors such as rates of post-impact deceleration could be different, or other issues may be at play. But we cannot study this further because the police had not released the evidence to allow a more detailed analysis. All we can say is that something appears to be inconsistent.
After the Humboldt Broncos collision a Canadian Parliamentary Committee was formed to study bus passenger safety. Hearings were held though the spring of 2019 and a number of witnesses attended providing their opinions as to how we can improve passenger safety. At the same time a CBC Fifth Estate documentary was focusing the public’s attention on the lack of seat-belts on school buses. Many differing opinions were expressed. Regrettably, the Parliamentary Committee was disbanded when the federal elections commenced and it is yet to be determined if a new committee will be formed to continue the discussion.
Myself and Professor Ahmed Shalaby, of the University of Manitoba Transportation Department, co-wrote a brief to the Parliamentary Committee with our observations and recommendations. One of those observations was the lack of open, independent investigation that is currently conducted whenever a major bus collision occurs. While police are supposed to be impartial in their investigations, there are practical difficulties that interfere with that impartiality. And, as witnessed in the case of the Humboldt Broncos crash, objective evidence can become hidden from the public’s eye. It was our observation that in the U.S. the independent National Transportation Safety Board (NTSB) is empowered to investigate bus collisions such as the Broncos incident. But that is not so in Canada. In Canada the Transportation Safety Board (TSB) would only become involved in a bus collision if that bus was in collision with another mode of transportation such as a railway train, an airplane or ship. This provides an extreme limit on its ability to document bus safety problems. Thus we recommended that the mandate of the TSB be changed. Ours was the only submission that called for that change.
We see once again that a major bus crash has occurred at Smoky Lake. Although there is no current information that a fatality occurred, the fact that several passengers sustained critical injuries suggests that the possibility of a fatal result is not out of the realm of possibility. Even so, the levels of injury are an important matter that needs detailed and unbiased documentation that is released to the public. Much like the Humboldt Broncos case, it is unlikely that this will happen.
There is an overall lack of transparency with respect to collision data in Canada that was also one of the observations made in the Shalaby & Gorski brief. While various agencies conduct investigations and research studies these are rarely available to independent researchers and to the public in general. If we are to increase our efficiency in studying road safety problems this lack of transparency needs to be addressed.