Breach of Duty

Most personal injury claims are based on negligence (carelessness), and you have to prove breach of duty to win a negligence claim. Proving breach of duty is not enough by itself to win, but it is necessary whether you seek to win, to name a few examples, a car accident claim, a bicycle accident claim, or a pedestrian accident claim. Proving breach of duty is easy in some cases, and tricky in others.

Background: Introduction to “The Reasonable Person”

Background: Introduction to “The Reasonable Person”

The so-called “reasonable person” decides a high number of personal injury claims, even though they don’t actually exist. The reasonable person is a hypothetical individual who possesses a quality that none of the rest of us have: complete rationality. 

If we want to know whether a defendant was negligent, one way of making this determination is to ask whether a “reasonable person” would have acted in the manner that the defendant did. If they would have acted the same, then the defendant was not negligent. If he would have acted differently, then the defendant might have been negligent.

Context: The Basic Elements of a Negligence Claim

To win a negligence claim, you need to prove five factors–duty of care, breach of duty, damages, actual cause, and proximate cause.

Duty of Care

Almost everyone owes everyone else a duty of reasonable care to avoid injuring others. Some people owe a heightened duty of care to others (see below). 

Breach of Duty

A defendant breaches their duty of care by doing something they shouldn’t do (dropping a banana peel on the floor, for example), or by failing to do something they should do (failing to fix a stairway railing, for example). 


“Damages” normally include a physical injury. Once you prove that you suffered a physical injury, you can add elements of psychological harm, such as pain and suffering, to your claim. You must be able to prove your damages, however.

Actual Cause

The defendant’s breach of duty must have been the actual cause of your injuries. In other words, it must be true that if the defendant had not breached their duty, you would not have suffered your injuries.

Proximate Cause

Proximate cause exists when a “reasonable person” would have foreseen that breaching the duty of care in the manner that the defendant did would lead to the injuries that the defendant suffered. If even a reasonable person would not have foreseen the harm, the defendant is not liable. 

The purpose of the “proximate cause” requirement is to prevent accident victims from being able to file a claim over a freak accident. 

The Burden of Proof

The burden is on the person making a claim to prove that claim. Initially, that places the burden of proof on the injury victim to prove the defendant’s liability. If the defendant offers an affirmative defense (the statute of limitations deadline has already expired, for example), the defendant is the one who must prove it.

The person with the burden of proof must prove it by a “preponderance of the evidence.” A preponderance of the evidence is enough evidence to tilt the scales of justice in your favor, even only slightly. If you can prove a 51% likelihood that your claim is true, for example, the claim is established.

Different Levels of the Duty of Care

Not every defendant is subject to the same duty of care. Following are three commonly-applied levels of the duty of care:

  • The duty of ordinary care: This is just the duty of care that every mentally competent adult owes to everyone else.  
  • Premises liability: The owner or manager of property (such as a shop) must inspect their property for latent dangers, and must repair or warn against any unreasonable dangers.
  • Professional duty of care: Someone with professional training is expected to use that training in the service of their clients. A physician, for example, must exercise a professional duty of care when treating patients. The same standard might not apply if they render first aid on the roadside after witnessing a traffic accident.

It is not always obvious what the specific demands of a given duty of care might be in a given situation.

Proving Breach of Duty

Following are the most common ways of proving breach of duty.

Common Sense

“Common sense” is where the “reasonable person” standard most often comes into play. Suppose, for example, that the plaintiff suffered injuries in an accident that occurred while the defendant driver was “tailgating” the victim. “Tailgating” means driving too close, but how close is too close? Common sense can tell you.

Expert Testimony

The “common sense” of an expert witness is likely to be persuasive, at least if the expert is qualified and does not wilt under cross-examination.

Negligence Per Se

“Negligence per se” allows you to prove negligence by showing that the defendant violated a safety statute or regulation. The statute or regulation defines the duty of care. You still need to prove damages and causation to establish liability. 

Contact a Hamilton Personal Injury Lawyer for a Free Initial Consultation

Most Hamilton personal injury lawyers spend most of their time resolving negligence claims. Unlike lawyers in other fields, personal injury lawyers do not charge by the “billable hour.” Instead, they calculate their fee as a pre-agreed percentage of whatever amount of compensation they manage to secure for their client. 

You pay nothing (ever) unless you win compensation, and consultations are free. Take advantage of this state of affairs by contacting a personal injury lawyer for a free legal review of your case. Contact our legal team from Findlay Personal Injury Lawyers today at (905) 522-9799 to get started!