The London Fire Department provided the above photo a a pick-up truck that rolled over following a collision with another vehicle at Richmond and York Streets in downtown London on August 4, 2021. It was reported that there were no injuries.
This is a good opportunity to make some safety comments about the common habits of creating high-centre-of-gravity vehicles. We have heard the most-obvious problem that taller pick-ups, SUVs and Vans cause visibility problems in front and behind them, thus endangering pedestrians, particularly children But there are other reasons why putting lifters on your suspension is a bad idea. In recent years, many light vehicles have been built with short wheelbases, smaller track widths and taller heights. This is a recipe for disaster in an intersection collision because such a vehicle invariably rolls over. But that is not always a disaster. In fact, a low speed rollover can be very benign if occupants remain within the protective cage of their vehicle and nothing intrudes into where they are seated. The deceleration during a rollover can be in the range of 0.4 to 0.6g. This rate is lower than many instances where a driver applies maximum braking on a dry asphalt road.
The problem with rollovers is that you just don’t know. Decades earlier with few people wearing seat-belts we used to refer to the injury outcomes from rollovers as “dice in a box”. You shake the box and let the dice fall but the outcome is let to chance. And sometimes the “snake eyes” result in your death. With the advent of seat-belt usage and rollover “curtain” airbags much has improved. but it is still a risky result.
What persons believe about high centres-of-gravity is that they are safer when they are riding higher up. To some degree this is true. In many severe head-on collisions it has been observed that the vehicle that rode over the front end of the other would likely contain occupants whose injuries were less severe. The structure of the taller vehicle would penetrate the softer upper structure of the lower vehicle often resulting in structural intrusion and major injury results. But there is also a drawback to the higher centre-of-gravity idea.
When your vehicle rises over top of another it becomes “propelled into the atmosphere”, or lifted up, sometimes when the post-impact velocity of your vehicle is still high. Now you have a problem. Your vehicle is now launched, even if slightly, into the air and it becomes the “dice in the box” idea all over again. Your vehicle may roll but it may not be a soft landing on level ground. Your vehicle may strike a pole, tree, barrier, ditch, another vehicle or so many other unforgiving things. And this contact will often occur with the soft roof structure of your vehicle, resulting in structural intrusion. Vehicle manufacturers do not like to spend money on less likely dangers and so they do not believe that you need to be well protected from large vertical forces to the roof of your vehicle. So any impact of moderate severity can produce substantial roof crush. The experts believe you should be protected from soft rollovers on level ground not from major impacts to the roof region by immovable objects.
And the obvious problem with higher centres-of-gravity is that your vehicle is more prone to loss-of-control in curves and as a result of road surface irregularities combined with low friction levels such as in snowy or icy conditions.
The photo presented at the beginning of this article should be reminder. Soft, low-speed rollovers are generally not a safety problem so long as you stay inside your safety cage and nothing comes into where you are seated. But there is that issue of the “dice in a box”. Sometimes you just never know.
So, do not lift your vehicle any more than what the manufacturer has already done. There are safety consequences that you may not recognize.