It doesn’t take a rocket scientist to understand the dangers involved when a 40-ton semi-truck experiences a rollover. However, it is helpful to understand several fundamental laws of physics play a role in causing most truck rollovers.
An analysis by the Insurance Institute for Highway Safety found that there are more than 9,000 injuries and 300 fatalities attributable to rollovers of large trucks. Additionally, the damages from rollovers carry an estimated $3.5 billion dollar annual price tag.
Understanding the Causes
Most drivers understand the basic concept of center-of-gravity. This is the term for the point of stability in a fully loaded truck. When that center shifts, it is often a major factor in losing control of a truck and, in extreme cases, causing it to tip over.
Traveling along any curved path will create a force that pushes the truck into a lean in the direction of the turn. Called centrifugal force, the effect is made greater as the speed increases. Thus, experienced drivers know to slow down their speed and rate of turn to combat the effects of this force. The Federal Motor Carrier Safety Administration studied this problem closely in its Large Truck Crash Causation Study (LTCCS).
During this study, a rollover was defined as an accident involving “one or more vehicle quarter turns about the longitudinal axis.” Studying a sample of 967 crashes of Class 8 trucks that involved at least one fatality, the results showed rollovers were involved in at least 9 percent of all accidents. That extended to a rough estimate of at least 13,000 rollovers during the two-year period of the study.
The study also concluded, not surprisingly for most professional truckers, that rollovers were the most dangerous and caused the most damage to other drivers and vehicles. In addition to the well-known issue of center-of-gravity shifts, they indicated that driver errors were at the heart of most rollover accidents.
They attributed the causes to:
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Excessive speeds in curves
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Misjudging the sharpness of curves
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Drifting and then over-steering to correct the drift
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Badly distributed loads
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Improperly secured loads
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Maintenance issues with suspensions and tires
The study also explained the physics that applies to inertia and bodies in motion. The front wheels of the cab move faster than the attached trailer and load. The combined effect of rapid movement of the front and slower movement of the rear add to the loss of control and, ultimately, the shift in the center of gravity that makes a rollover possible.
Rocket Scientists to the Rescue
Thankfully, it is this role of scientific principles that has motivated a group of non-truckers to attack the problem of rollovers. Axicle Engineering is a tech startup that is made up of a team of rocket scientists and engineers from the automotive industry. The team includes founder Steve Krug, who was an engineer at Tesla with an aerospace background.
Krug was concerned with finding an effective way to reduce highway accidents and the deaths and injuries they cause. He and other Tesla engineers who worked on the Tesla Semi project understood the physics and dangers of rollovers. They also established two priorities: dangers for the drivers of semis and the high costs of damage to the cabs in a rollover.
Their brainstorming produced a patent-pending prototype fifth-wheel device they call the Truck Anti-Roll System, or TARS. This system is designed to sense a pending rollover and, at a critical moment, detaches the cab from the trailer and its load. That leaves the driver in an upright vehicle and only the load tipped over. Tests thus far show a 99.9 percent accuracy in accessing a pending rollover.
One early supporter of this potential solution is Ryan Scott of Kysar Millenium Leavitt Insurance. He was quoted in American Trucker as stating that TARS “…can protect the two most important assets … the driver…and the cab itself.”
Axicle reports it already has $30 million in orders for its initial 7,500 units at $4,000 per unit. It is projected that insurance credits from companies such as Kysar will provide a payback for the unit in less than three years.
American roads will soon be safer thanks to an innovative group of rocket scientists.
