Unsecured loads are a danger to the occupants of a vehicle and this is an issue that is often misunderstood.
Constable Kerry Schmidt of the Ontario Provincial Police (OPP) posted several photos on the OPP West twitter account showing a van loaded with various supplies and equipment, including a law tractor. These photos are re-produced below.
The danger of insecure loads does not lie just with the possibility that they may spill onto the roadway. But there are grave dangers that exist for the vehicle occupants if such a loaded vehicle is involved in a significant impact.
In the last of the three photos shown above the pile of lumber clearly blocks the driver’s view of anything to the right of the vehicle. In such an instance a collision is more likely to occur. The type of collision that might occur is not guaranteed and could involve a significant impact to the side, front or even to the rear of the vehicle. The results of such impacts can be complicated but previous investigations show how they can be deadly.
As an example, say that you have a 100 kg load in the back of your van. In a significant impact your vehicle may be slowed down by 40 km/h. Converted, this is equivalent to a change-in-velocity of about 11.11 metres per second. But such major collisions are often completed in about 1/10th of a second. So, in fact, the change-in-velocity is actually 10 times higher or equivalent to 400 km/h, or 111 metres per second. A “g” is the acceleration attained due the earth’s gravitational pull which is equal to 9.81 metres per second squared. As an example, if you jump off a cliff your body will be accelerated toward the ground at a rate of 9.81 metres every second. Thus in terms of ‘gs’ the rate at which you slow down in a 40 km/h impact is about 111 divided by 9.81 or about 11.3 gs.
Another way to look at it is to have a 200 pound man sit on your chest and you can appreciate the difficulty you might experience. Now multiply that weight by 11, or 2200 pounds, and this is the type of force we are dealing with. Is this healthy? Could you survive a 2200 pound weight being applied to your chest? That is the weight of a small car. Clearly not.
Returning to the example of our improperly loaded van, there is a lawn tractor positioned in the rear and there is no indication that it is tied down in any way to the structure of the vehicle. How much does a lawn tractor like this weight? Using the example above, it could surely weight 200 pounds. Now, what could happen if our van driver is involved in the 40 km/h change-in-velocity we discussed above? This lawn tractor is now an unsecured “cannon ball” that continues to travel forward within the vehicle interior even though the vehicle itself is being stopped by the force of the impact.
So let us say the van driver is wearing his seat-belt and the air bag deploys thus providing excellent protection. But what about that unsecured “cannon ball” that has not been slowed down by a seat belt or air bag. This 2200 pound object now drivers into the rear of the driver’s seat back after the driver and van have lost most of their forward motion.
Stop and think for a moment. Do you really think that automotive engineers are so cleaver that they can devise the creation of a seat back that can stop a 2200 pound object in a fractional distance that could be needed to protect the driver? Wonderful things have been accomplished but this miracle is still awaiting discovery. Essentially nothing will stop this extreme weight from striking the driver. What can be beneficial is if the object can be re-directed so that it travels to another part of the interior that does not contain a passenger.
So my recommendations are as follows. Number one, never allow such a situation to occur as shown in the photos above. The cost of using a small trailer or other vehicle which can transport your equipment and heavy supplies is worth the additional cost in comparison to losing your life.
Secondly, if you absolutely need to carry some relatively heavy cargo in your vehicle’s interior there are procedures that can be used to minimize your danger. For a frontal impact recognize that most severe frontal impacts will involve the left portion of the front end and this will induce counter-clockwise rotation. Thus, if you are not carrying passengers on the right side of vehicle, place the heavy object on the right side of your vehicle. When the typical, severe, frontal impact occurs the heavy cargo is more likely to travel into the right portion of the interior and you could be saved.
Next, place your have cargo as low as possible, like on the floor for example. Consider also whether you have created the undesirable conditions that could cause the cargo to be ramped upward during a severe impact and make proper adjustments where possible.
Thirdly, place your cargo in contact with a solid portion of the vehicle interior. By doing so you may be able cause the cargo to begin slowing down as early as possible, or close to the timing of the slowing of the vehicle structure.
And fourthly, and most importantly, secure the cargo to the structure of your vehicle so that it has an opportunity to ride down the collision along with the vehicle structure. If you like, view this as a “seat-belt” for your cargo.
None of the above procedures can prevent you from sustaining major or fatal injuries when carrying heavy cargo but they can minimize the chances. Otherwise, understand the dangers and use the proper vehicle for such transportation.