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Jackknife Trucking Accidents


Our Canadian highways are filled with 18-wheelers that pose a threat to innocent persons on the road. These dangerous vehicles are often poorly maintained and driven by tired truckers. Their victims are usually oblivious to the danger of the 80,000 pounds that could careen into their vehicle at any given moment. Of course, there are many safe drivers and some companies that concentrate on safety. However, the urgency to cover the miles in as short of a time as possible, is the norm, with profitability being the driving force. Needless to say, given the amount of trucks on our roads, there is a lot that can go wrong. One of the most horrific types of trucking accidents is called the “jackknife” trucking accident – which is explored below.

What is a Jackknife Trucking Accident?

Large trucks are generally made up of a cab and a trailer. A jackknife trucking accident is when the trailer of a large semi truck swings out from the cab, forming a 90° angle similar to the “V” shape of a pocket jackknife. Jackknife accidents are typically caused by the uncontrolled braking of a tractor-trailer, Or when the tractor trailers accelerate too harshly or too early on a corner. When this happens, it can cause the drive wheels to spend, especially when the truck is lately loaded. This can cause serious problems for semi’s or truck trailer combinations. When the drive wheel spins, the semi trailer or trailer can continue forward under its own momentum, pushing the drive wheels sideways and jackknifing the truck. This would typically occur when quartering on a road surface which is wet, slippery or has a negative camber.

The following video depicts a jackknife trucking accident:

Jackknife trucking accidents are extremely dangerous – particularly on busy roadways or highways. The jackknifing of a trailer can cause brutal accidents when the trailer, which rotates about the tractor, extends to adjacent lanes blocking the incoming or following traffic.  Vehicles can easily get swept up by the swinging trailer and even moreso, can get wedged under the trailer. Motorists sometimes can’t see a jackknifed truck until it’s right in front of them, especially if it’s been spread across other lanes into the opposite direction. On a highway with a speed limit of 100 km/hr, stopping in time to avoid an unexpected collision is difficult. 

How Common Are Jackknife Accidents?

In Canada, it is estimated that more than 90% of our consumer goods are shipped via semi truck, and as of 2020, there are more than 1 million transport trucks regularly traveling across the country. Further, approximately 10,000 Canadians are seriously injured in trucking accidents every year, while around 2,000 Canadians are killed in trucking accidents.

Jackknife accidents are among the most common type of trucking accidents that occur in Ontario due to the variety of factors that could influence these collisions – and in fact – jackknife accidents are one of the most common accidents that result in death. The harsh weather conditions of Canada’s winters, the high volume of traffic on our 400-series highways, and the number of road users who travel each day all influence the chances of trucking accidents that can take lives and put survivors at risk.

What Causes a Trucking Jackknife Accident?

There are a variety of factors that can cause a jackknife trucking accident. However, sudden braking is the most common cause of most trucking jackknife accidents. A semi truck can weigh up to 80,000 pounds fully loaded, while the average car weighs up to 4,000 pounds. As a result, a truck requires more room to brake than a motor vehicle does and can’t stop on a dime if sudden circumstances require it. When the truck does stop too quickly, the trailer cannot move forward due to the cab, and since it is being pulled behind the cab, it swings out to the side instead.

Other common causes of jackknife trucking accidents we have seen include:

  • Accelerating too harshly or too early on a corner, especially if the road surface is too wet or slippery
  • Speeding or taking a sharp turn too fast 
  • Improper lane changing or merging 
  • Not adjusting for bad weather conditions such as ice and snow 
  • Driver inexperience, such as losing control when navigating a curve
  • Equipment malfunction or maintenance issues, such as locked brakes 
  • Oversized loads causing imbalance weight distribution
  • Shifting cargo
  • Distracted driving
  • Impaired driving
  • Driving while fatigued 
  • Badly worn or bald tyres are more likely to puncture or blow out. Lack of tread depth also reduces grip on slippery surfaces and this can lead to braking skids, poor steering response and jack knifing

Jackknife Accidents and Under-Ride Accidents

One of the many reasons why jackknife trucking accidents can be so severe and potentially deadly is because they can lead to under-ride accidents, which are arguably the worst type of trucking accident. 

Under-ride accidents occur when a vehicle cannot stop in time to avoid striking a truck and end up sliding underneath the side or rear of the trailer. This can lead to devastating injuries and often horrific death for the driver and occupants of the car, as they can be crushed, decapitated, or suffer severed limbs. Those who survive are at serious risk for traumatic brain injuries, spinal cord injuries, and other devastating catastrophic consequences.

Underride trucking accidents often happen at night or during sun-setting/rising conditions. Underrides normally happens when a truck jackknifes, or when a truck driver is attempting to cross a street or make a left-turn into a street and the car runs underneath the side of the trailer. Rear underride trucking accidents happen when the a car rear ends a trailer, particularly when the truck is stopped or parked and there are no warning markers, or they have been improperly placed in relation to the truck’s position.

Some trucks are equipped with under-ride guards, which are u-shaped metal bars that hang from the back of larger commercial trucks to prevent cars from sliding underneath in the event of an accident. While these safeguards add extra protection and can prevent fatal consequences, not every truck that drives on Ontario’s roads has them installed.

The following is an example of a underride trucking accident:

Serious and Catastrophic Injuries From Jackknife Accidents

Jackknife trucking accidents can lead to serious injuries and even wrongful death. The sheer size difference between a semi truck and a motor vehicle almost always leaves the car driver with more devastating consequences than the truck driver.

While any car accident has the potential to cause a variety of catastrophic, severe, or life-changing injuries, these are some of the most common consequences of jackknife trucking accidents:

If You’ve Been Involved in a Trucking Accident, we can Help. Schedule your case with an Experience Trucking Accident Lawyer today.

We understand that commercial truck accidents can be devastating, and that if you or a loved one has been involved in a trucking accident, life can change in a moment. Our trucking accident lawyers have represented trucking accidents victims since 2003 and have the experience and knowledge you and your family deserves. Although we cannot undo the collision and your losses, we can hold wrongdoers responsible and make sure that you and your family are protected financially, for life. We can – make you whole again.

Matt Lalande and the dedicated team at Lalande Personal Injury Lawyers handle cases where victims have been seriously hurt in a collision and crashes involving a large semi trucks, cargo trucks, delivery trucks, big rigs, 18 wheeler, or other commercial vehicle. You are not alone in dealing with challenging truck accident injuries.

Contact us nationwide by calling our trucking accident lawyers toll free at 1-844-LALANDE, or local in the Hamilton/GTA at 905-333-8888. Alternatively you can contact us through our website by sending us a confidential email and we will respond to your inquiry without any delay.



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