Jackknife Truck Accidents: Why They're So Dangerous and How to Get Legal Help in Ontario

A jackknife truck accident happens when a semi-truck’s trailer swings out at a sharp angle. It usually occurs when the wheels lock up during hard braking, on slippery roads, or at speed. Because a loaded truck weighs up to 80,000 lb, a jackknifing trailer can sweep across several lanes and cause deadly multi-vehicle pile-ups. If you were injured, I’m an experienced Ontario truck accident lawyer. Contact me for a consultation.

What Is a Jackknife Truck Accident?

A jackknife truck accident occurs when part of a tractor-trailer skids sideways and the tractor and trailer fold toward each other in a “v” angle of less than 90 degrees. This can develop in two ways:

• Trailer jackknife: The trailer wheels lose traction or lock while the tractor continues moving, causing the trailer to swing sideways toward the cab.
• Tractor jackknife: The tractor’s drive wheels lose traction, causing the rear of the tractor to swing sideways while the trailer continues pushing forward.

Jackknifing can happen when the wheels lose traction. Ice, snow, and freezing rain can make this loss of traction particularly dangerous on Ontario highways such as the QEW and Highway 403.

What Does it Mean When a Truck Jackknifes?

When a truck jackknifes, the tractor and trailer are no longer travelling in a straight line and begin folding toward each other at a sharp angle.

Trailer Jackknife Vs. Tractor Jackknife — What’s the Difference?

In a trailer jackknife, the trailer swings outward while the tractor continues forward, while in a tractor or drive-axle jackknife, the tractor rotates or swings while the trailer continues pushing it forward.

Why Trust Me, Derek Wilson, for Your Jackknife Truck Accident Claim?

I’m a Hamilton truck accident lawyer who has practised personal injury and insurance litigation for more than 30 years.

Before representing injured plaintiffs, I worked for insurance companies. That experience gives me direct knowledge of how insurers investigate claims, assess liability, and evaluate injuries.

Clients who choose my law firm receive:

• More than 30 years of experience focused on personal injury and insurance litigation.
• Direct access to me, who personally handles each file.
• A deliberately limited caseload designed to allow personal attention to each claim.
• Recognition by Best Lawyers and Best Law Firms, along with membership in the Law Society of Ontario and Hamilton Law Association.
• More than 100 five-star Google reviews.
• A free initial consultation.

For someone looking for a Hamilton truck accident lawyer after a serious commercial-vehicle crash, I work on a contingency-fee basis, meaning you pay legal fees when we recover compensation for you.

Why Does Experience Matter in a Jackknife Truck Accident Case?

Experience matters because determining why a tractor-trailer jackknifed can require evidence that does not exist in an ordinary car accident claim. An experienced accident lawyer in Hamilton can also identify potential defendants.

Why Are Jackknife Truck Accidents So Dangerous?

Jackknife truck accidents are because of several factors:

• Large vehicle mass: A heavy commercial tractor-trailer carries far more mass than a passenger car, increasing the forces involved in a collision.
• Trailer sweep: As the trailer swings sideways, it can strike vehicles in adjacent lanes, or push them into other traffic.
• Highway speeds: Jackknife crashes frequently occur on major roads where vehicles may be travelling at 65 km/hour or faster.
• Underride risk: A smaller vehicle can collide with or travel underneath the side or rear of a trailer, creating a particularly severe impact.
• Multiple-vehicle collisions: A jackknifed truck can suddenly block several lanes and trigger a chain reaction involving vehicles behind it.
• Secondary impacts: Vehicles that avoid the truck itself may collide with barriers, other motorists, or debris.

On busy routes including the QEW, Highway 403, the Linc, and Red Hill Valley Parkway a jackknifed tractor-trailer can create a hazard across several lanes before approaching drivers have enough distance to stop.

What Injuries Are Most Common in Jackknife Truck Accidents?

Jackknife truck accidents can cause:

• Traumatic brain injuries
• Spinal cord injuries
• Broken bones
• Internal injuries
• Neck and back injuries
• Whiplash and other soft-tissue injuries
• Lacerations and crush injuries
• Psychological trauma
• Fatalities

A seriously injured person may need long-term support while also dealing with time away from work.

Can You Survive a Jackknife Accident?

Yes. People can and do survive jackknife truck accidents, but significant and life-changing injuries are common.

What Causes a Truck to Jackknife?

A truck usually jackknifes when its tractor or trailer begins skidding out of alignment with the rest of the vehicle. This can happen for several reasons:

• Sudden or hard braking can cause wheels to lock or lose traction.
• Excessive speed reduces time or distance to brake safely.
• Braking or turning on a curve can destabilize a tractor-trailer.
• Weather increases the risk of a skid on Ontario roads.
• Poorly maintained brakes or other braking-system defects can contribute to loss of control.
• Tire failure can destabilize the truck.
• Unbalanced, shifting, or unsecured cargo can change the trailer’s centre of gravity and make it harder to control.
• An empty trailer has less weight pressing its tires against the roadway and can be more susceptible to traction loss.
• A fatigued driver may react too late, misjudge traffic conditions, or brake improperly.
• Impairment or distraction can cause a driver to brake or steer abruptly to avoid a hazard.
• A driver who has not been properly trained may be less prepared to control a developing skid.
• Poor maintenance, inadequate supervision, or schedules that encourage unsafe driving can contribute to a collision.

The cause may identify where negligence occurred. For example, excessive speed may point to driver negligence.

Are Jackknife Accidents Preventable?

Yes, many jackknife accidents are preventable when commercial drivers and trucking companies follow appropriate safety practices.

Ontario also regulates commercial-vehicle safety and driver hours. Drivers subject to provincial hours-of-service requirements generally must have at least 10 hours off duty in a day and cannot drive more than 13 hours in a day, subject to applicable rules and exceptions.

Why Do Trucks Jackknife in Winter or on Ice?

Trucks are more likely to jackknife on ice or snow because reduced tire traction makes it easier for the tractor or trailer to begin sliding sideways.

Who Is Liable for a Jackknife Truck Accident in Ontario?

Liability for a jackknife truck accident in Ontario depends on what caused the truck to lose control. Potentially liable parties include:

• The truck driver, in cases of speeding, following too closely, hard braking, distracted driving, impairment, fatigue, or other unsafe driving.
• The trucking company or motor carrier, if driver’s conduct, negligent hiring, training, supervision, scheduling, or maintenance practices led to the accident.
• A cargo loading company, in cases of improperly distributed, overloaded or unsecured cargo.
• A maintenance provider, if poorly maintained brakes, tires, or another mechanical system contributed to the crash.
• A manufacturer, if defective vehicle components create a product-liability issue.
• A road authority, if design or maintenance of the roadway caused the accident.

Ontario commercial vehicles operate within a regulatory framework that includes the Highway Traffic Act, Commercial Vehicle Operator’s Registration requirements and hours-of-service rules. For example, Ontario’s Highway Traffic Act requires vehicle braking systems to be maintained in good working order, while provincial commercial-vehicle rules impose limits on driving and on-duty time.

Who Can be Held Responsible for a Jackknife Truck Accident?

Anyone whose negligence contributed to the jackknife accident may potentially bear responsibility. That can include the driver, trucking company and third parties responsible for cargo, maintenance or defective equipment.

Can I Claim if the Truck Driver Skidded on Ice?

Potentially, yes. If the driver skidded on ice because they were not driving at a safe speed or if the tires were not correctly maintained, this can still point to negligence.

How Do Lawyers Investigate Jackknife Truck Accidents?

Lawyers investigate jackknife truck accidents by gathering evidence to determine why the truck lost control and who contributed to the crash. This may include the following steps:

1. Preserve evidence. A lawyer can send a spoliation/evidence-preservation letter to the trucking company and other parties that relevant evidence must be preserved.
2. Obtain electronic truck data. Commercial trucks may contain an Electronic Control Module (ECM), Electronic Logging Device (ELD) data, or other systems that record information relevant to the crash. This data may help establish speed, braking and other events leading up to the collision.
3. Examine maintenance and inspection records. These records can reveal problems involving brakes, tires or other components that may have contributed to the jackknife.
4. Review the carrier’s safety records. A trucking company’s Commercial Vehicle Operator’s Registration (CVOR) and related records may provide relevant information about its compliance and safety history.
5. Obtain police evidence. The collision report, photographs, measurements, officer observations, and any charges laid after the crash can provide evidence.
6. Locate witnesses and video. Witness statements, dash-cam footage, and traffic or surveillance cameras may show how the truck was moving immediately before it jackknifed.
7. Investigate possible distraction. Where legally obtainable and relevant, cell-phone records or other evidence may help determine whether the driver was distracted.
8. Retain experts when necessary. Accident reconstruction engineers can analyze vehicle movement, braking, road conditions, and collision dynamics. Medical and financial experts may establish the extent and long-term cost of a person’s injuries.

A commercial truck investigation can be more complicated than an ordinary car accident claim because critical evidence may be held by the trucking company or other third parties. There may also be several potentially responsible parties and insurers involved.

What Evidence Is Used to Prove a Jackknife Truck Accident Claim?

The evidence used in a jackknife truck accident claim depends on the cause of the crash, but may include vehicles data and records, truck carrier data, police reports, videos and photos of the accident, and other evidence available.

A lawyer investigating a jackknife truck accident looks at the evidence together to determine how the crash developed and who may be legally responsible.

Why Is it Important to Act Quickly After a Truck Accident?

It is important to act quickly because evidence relevant to a truck accident can be lost, overwritten, or become more difficult to obtain over time.  A lawyer can take steps to request that relevant records and electronic evidence be preserved.

What to Do After a Jackknife Truck Accident in Ontario

After a truck accident, take these steps, if you are uninjured enough to do so:

1. Get to a safe location and call 911. Follow emergency personnel’s directions and do not put yourself at further risk to collect evidence.
2. Seek medical attention. Get assessed after the collision, particularly if you struck your head, lost consciousness, or have significant pain.
3. Document the scene if it is safe to do so. Take photographs or video of the vehicles, their positions, damage, road conditions, skid marks, and surrounding area.
4. Record information about the truck. Note the trucking company’s name, licence plate, insurance slip and other identifying information visible on the tractor or trailer.
5. Get witness information. Record the names and contact information of people who saw the collision or the truck’s movements before it jackknifed.
6. Notify your automobile insurer promptly. Report the accident and ask about the process and deadlines that apply to your claim and any available Ontario accident benefits.
7. Keep your records. Save medical documents, receipts, correspondence with insurers and records showing missed work or other accident-related expenses.
8. Be careful when discussing fault. Give police and your own insurer the information they require, but avoid speculating about the cause of the collision or accepting responsibility for anything.
9. Get legal advice before resolving the claim. An accident lawyer in Hamilton can explain the applicable claims and deadlines before you sign a release or accept a final settlement.

You generally have a two-year limitation period to file a claim, but notice deadlines occur much sooner, and evidence can go missing in hours or days. When in doubt, consult with a lawyer sooner rather than later.

What Should I Do Immediately After a Jackknife Truck Accident?

Immediately after a jackknife truck accident, move to safety if possible, call 911 and seek medical attention. Once you are safe, document what you reasonably can.

How Long Do I Have to File a Jackknife Truck Accident Claim in Ontario?

Ontario personal injury claims are generally subject to a two-year limitation period, but the deadline that applies to a particular claim depends on the circumstances. Insurance claims and claims involving certain defendants can also involve other notice requirements or deadlines.

Compensation Available After a Jackknife Truck Accident Injury

What a person can recover depends on factors including their insurance coverage, the circumstances of the crash and the nature and long-term effect of their injuries.

Ontario’s Statutory Accident Benefits Schedule provides a system of benefits for people injured in automobile accidents. Following changes that took effect July 1, 2026, the benefits available to a particular person can depend in part on the applicable policy and optional coverage, but may cover:

• Medical and rehabilitation benefits
• Attendant care benefits
• Income replacement benefits
• Caregiver benefits
• Other benefits available under the applicable policy
• Death and funeral benefits in fatal accident cases

A person injured because of another party’s negligence may also have a tort claim for losses caused by the accident. This claim is separate from the Accident Benefits process and requires establishing legal responsibility.

Depending on the case, damages may include compensation for pain and suffering, medical and care expenses not covered by OHIP, income loss and expected loss of future earning capacity, care needs, and other losses.

What Compensation Can I Recover After a Jackknife Truck Accident?

Compensation may be available for the financial and non-financial consequences of your injuries. The specific categories depend on your circumstances, available insurance coverage and whether another party can be held legally responsible.

How Much is a Jackknife Truck Accident Claim Worth?

There is no standard settlement amount for a jackknife truck accident claim because every individual’s injuries, recovery, income losses, and future needs are different.

Speak With Me, Hamilton Jackknife Truck Accident Lawyer Derek Wilson, Today

If you were injured in a jackknife truck accident in Hamilton or elsewhere in the Golden Horseshoe, I can review what happened and explain your legal options. Commercial truck claims can involve multiple parties, insurers and sources of evidence, so getting advice early can help ensure important issues are identified.

Derek Wilson Injury & Disability Law represents injured people in Hamilton and surrounding communities, including Stoney Creek, Burlington, Grimsby, Niagara, Brantford and Cambridge.

Your consultation is free and there are no upfront legal fees, so call me at 905-769-0418 for your free consultation.