The primary element of negligence liability is the negligent act - a failure to take care for the safety of the plaintiff. In determining the appropriate degree of care, it is useful to have some standard against which to measure the conduct of the defendant. One could suggest a number of possible standards such as the degree of care shown by a parent to a child, the care of a compassionate and humane person, or the care friends exhibit to each other.2The common law has, however, typically resorted to the reasonable person when it is in need of a normative standard of conduct, and negligence law is no exception. The standard of care that must be met in the tort of negligence is that of the reasonably careful person in the circumstances of the defendant.
The standard of the reasonably careful person was authoritatively established in the English case of Vaughan v. Menlove.3In that case, the defendant built a haystack close to the boundary between his land and that of the plaintiff. The haystack was so poorly constructed that it gave rise to a risk of spontaneous combustion. The defendant was warned of the danger but he did not take adequate steps to deal with it. In due course, the haystack caught fire and the fire spread to the plaintiff’s property where it destroyed some cottages. At issue was the appropriate measure of the defendant’s conduct. It was argued that the defendant was not negligent because he had acted honestly, in good faith, and to the best of his judgment. To impose liability would punish him, unfairly, for not being of a higher intelligence. Chief Justice Tindal rejected that argument and held that the defendant must "adhere to the rule which requires in all cases a regard to caution such as a man [person] of ordinary prudence would observe."4The defendant was held liable.
The standard of care of the reasonable person is an objective standard. It focuses on the defendant’s conduct and its sufficiency with reference to that of a reasonable person. No consideration is given to the defendant’s thought process or his subjective awareness of the danger that his conduct poses to others. Therefore, it is not necessary to show that the defendant was a conscious risk taker. Indeed, the test of the reasonable person excludes all the psychological and physical traits that make each person different. A person’s ability to apprehend and avoid danger may well depend, in part, on his intelligence, reaction time, strength, courage, memory, coordination, maturity, wisdom, temperament, confidence, dexterity, and many other personal attributes. The objective test excludes all of these individual characteristics in its determination of reasonable care.5The reasonable person is not, therefore, any single person. It is not appropriate for a judge or juror to evaluate the defendant’s conduct on the basis of what she would have done in similar circumstances.6Neither is the average person the reasonable person. The average person may fail to exercise sufficient care in some circumstances. For example, the average driver is prone to frequent acts of negligence. In truth, the reasonable person is an abstract legal construct, used to set appropriate standards of conduct in society. That standard of conduct is determined by taking into account both the practical realities of what ordinary
people do and what judges believe they ought to do.7It is not, however, a standard of perfection. The reasonable person may make mistakes and errors of judgment for which there is no liability. Nevertheless, the reasonable person is more alert to risk, and cautious by nature, than most of us.
The standard of the reasonably careful person has displayed surprising resilience and longevity. It is rarely questioned. There are a number of reasons for this. First, an objective standard presents fewer problems in respect of the proof of negligence. It is much easier for a plaintiff to establish the words and actions of the defendant as required by an objective test than to establish the defendant’s thought process that accompanied that conduct as required by a subjective test. Administrative convenience and expedience are, therefore, served by an objective standard. Second, it is good policy to require a uniform standard of safety and security in society. Citizens may then anticipate and expect a reasonable degree of care from others and may act in reliance on the fact that these standards have legal recognition and are enforceable. Third, the adoption of an objective standard more efficiently promotes the compensatory functions of negligence law. The use of a subjective standard of care, which imposes liability only on conscious risk takers, would significantly reduce the number of persons compensated by negligence law.8Most defendants in negligence cases are not conscious risk takers. They are people who have done their best but have failed to reach the normative standard of care by reason of mental or physical characteristics, momentary distractions, inadvertence, oversight, and other morally blameless reasons. Finally, the objective standard of the reasonably careful person in the circumstances has provided judges and juries with an abstract and malleable concept that can be applied to all activities, in all circumstances, at any time. Indeed it is capable of perpetual application as society evolves in this century.
When applying the standard of care to the facts of a case, courts have found it useful to review a number of factors that guide a reasonable person in the regulation of her conduct.9The most significant of these
is the concept of a reasonably foreseeable risk. Conduct is negligent only if it carries a risk of damage that a reasonable person would contemplate and guard against. In addition, courts routinely consider the likelihood of the damage occurring, the seriousness of the threatened harm, the cost of preventive measures, the utility of the defendant’s conduct, any circumstances of emergency, compliance by the defendant with approved practice or custom, and the defendant’s post-accident precautions. Other more controversial and elusive factors such as judicial policy, economic factors, the equity of the individual case, and the psychological phenomenon of hindsight bias may also be influential.
The central element in applying the standard of reasonable care is the concept of a reasonably foreseeable risk. The reasonably careful person avoids creating a foreseeable risk of injury to others. The concept of foreseeability may not, in itself, be sufficient to support a finding of negligence because other factors must be considered, but it is an essential component of liability. Four decisions of the Supreme Court illustrate the pivotal role of reasonable foreseeability. All four cases involved children who were injured when they came into contact with high-voltage electric wires under the control of the defendant power corporations. The defendant was found to be negligent in two of them.
In Gloster v. Toronto Electric Light Co.,10a boy aged eight-and-a-half years was injured when he reached out and touched a live wire that was just fourteen to twenty inches away from the public bridge on which he was standing. The danger was obvious to a reasonable person and the defendant was held to be negligent. In Amos v. New Brunswick (Electric Power Commission),11the defendant had allowed a poplar tree to grow up through electricity lines so that they were obscured from sight. Children were known to play in the area. The plaintiff was nine. He climbed to the top of the tree and was severely injured when the trunk or a branch of the tree swayed into the high-tension wires. The Court imposed liability. The risk was clearly foreseeable and a reasonably careful person would have trimmed the tree.
In the other two cases, the plaintiffs were unable to establish a foreseeable risk of injury. In Shilson v. Northern Ontario Light & Power
Co.,12a twelve-year-old boy was electrocuted as he walked across a narrow pipe stretching three hundred feet across a ravine that was twenty feet deep. When he got to the middle of the ravine, he reached out and touched a live wire four feet above the pipe. Warnings and barricades at each end of the pipe had not dissuaded him from venturing across. Given these unusual circumstances, the Court concluded that the defendant had "no reason to apprehend that children might find an opportunity of making the company’s high voltage wire . . . a source of danger."13In Moule v. New Brunswick Electric Power Commission,14the ten-year-old plaintiff was injured when he climbed a maple tree and came into contact with the defendant’s power lines. The defendant had taken some steps to reduce the danger. The maple tree had been trimmed of branches on the side facing the power lines and it was not possible to climb the tree directly from the ground. The plaintiff had initially scrambled into an adjacent spruce tree with the help of some boards nailed onto its trunk in the form of a makeshift ladder. From there he crossed over to the maple by way of a wooden platform. He then climbed the maple with the help of more nailed boards and straps. All of this "construction" appears to have...