Highest Degree of Confusion: The Case Against the Common Carrier Doctrine

The common carrier doctrine—a common law principle that holds common carriers of passengers to the “highest degree of care,” rather than the reasonable care standard that governs most negligence actions—has been accepted as the law in Arizona dating back to territorial days. The doctrine holds common carriers to a higher standard of care than the ordinary person is required to exercise; in other words, the common carrier must exercise greater than reasonable care. It remains unclear, however, what exactly constitutes “greater than reasonable” behavior. The real trouble arises if the liability of a common carrier must be weighed against another actor held to the reasonable care standard for purposes of comparative negligence analysis. When Arizona first adopted the common carrier doctrine, fact-finders were not yet charged with the task of allocating percentages of fault between negligent parties. Since the dawn of the comparative negligence era, the prospect of applying the common carrier doctrine in a uniform and equitable fashion is challenging, if not impossible.

Perhaps it is not a coincidence then that since Arizona embraced a comparative negligence scheme,1 the Arizona Court of Appeals has bucked against the traditional doctrine on at least two separate occasions.2 Most persuasively, the Lowrey court articulated a compelling argument for abandoning the common carrier doctrine, contending that the justifications3 for the common carrier doctrine can be wholly accommodated by the reasonable care standard, so the doctrine “adds no useful element to the ordinary negligence standard of reasonable care under the circumstances.”4

On December 6, 2011, the Arizona Supreme Court will hear Oral Argument in Nunez v. Professional Transit Management (CV-11-0186-PR), presenting the Court with an opportunity to revisit the common carrier doctrine. Despite the doctrine’s long history in the state, the Arizona Supreme Court should seize the opportunity to adopt the reasonable care approach to common carrier liability for five reasons: (1) to achieve a greater level of consistency with general principles of negligence law; (2) to simplify the job of the fact-finder and minimize the likelihood of confusion when apportioning liability to common carriers; (3) to promote judicial economy; (4) to modernize tort law to better reflect the realities of mass-transit in the 21st century; and (5) to encourage the growth of a robust public transportation system in Arizona.

Eliminating the common carrier doctrine in favor of the reasonable care under the circumstances standard would reconcile the law governing common carriers with the bedrock principles of negligence law. For most negligence actions, the reasonable care under the circumstances standard serves as the constant. Its elegance and effectiveness is derived from its flexibility. What constitutes reasonable care under the circumstances will change from case to case, but the standard of care remains constant.5 In other words, the reasonable care standard already requires certain actors (like common carriers) to take more precautions based on the individual circumstances of a case. Fact-finders can consider, for instance, the special relationship between a common carrier and a passenger when determining whether a carrier’s behavior met the standard of reasonable care. As a result, eliminating the common carrier doctrine would harmonize common carrier liability with the traditional foundation of negligence law.

Eliminating the common carrier doctrine would also simplify the fact-finder’s task in common carrier negligence actions and, in turn, minimize the likelihood of jury confusion. Requiring a common carrier to exercise greater than reasonable care “is a hard concept to make sense of and one very likely to be misunderstood.”6 As a result, when weighing the comparative fault between a common carrier and a passenger, the jury is charged with apportioning fault based on two different standards of care: the reasonable care standard governs the plaintiff’s actions, but the highest degree of care standard applies to the defendants. The task of apportioning fault in a negligence case is always challenging, but when jurors are asked to apply different legal standards to different actors the challenge grows more complex. If the basic negligence standard of reasonable care is applied to all parties, however, jurors can focus on sorting out the facts rather than trying to make sense of competing legal standards.

If common carriers are not held to a different standard of care, then the judicial resources exhausted on determining whether a party is a common carrier could be reallocated. From state to state, the scope of what constitutes a common carrier differs, particularly on the margins. For instance, should an escalator be considered a common carrier? What about an amusement park ride? Even if a jurisdiction has clear rules about which categories of transportation constitute common carriers, there is still likely to be litigation about whether a particular party was acting as a common carrier. If, for example, taxicabs are recognized as common carriers, then would a rideshare advertised on Craigslist be considered a common carrier? If a jurisdiction applies the common carrier doctrine, then the stakes are high for parties that might be considered common carriers. When facing the possibility of being held to the highest degree of care—and as a consequence face a higher likelihood of liability—those parties will likely attempt to escape categorization as a common carrier. In a scheme that simply applies the reasonable care standard, this aspect of common carrier litigation would disappear. Instead the sole focus would be on whether the behavior of the parties was reasonable in light of the circumstances, not on whether they fall within the scope of the common carrier definition.

Many of the legitimate justifications for the common carrier doctrine at the time of its creation have faded away with transformations in society. Although there was a time when mass transit was an ultrahazardous activity, technological improvements have greatly reduced this concern. Additionally, stricter government regulation has spurred innovation and prevented carriers from ignoring the safety concerns associated with mass transit. Applying anachronistic standards increases the risk of anomalous outcomes that could result from the confusion caused by the common carrier doctrine.

Finally, the common carrier doctrine creates a greater risk of liability for suppliers of mass transit, thus discouraging the growth and development of Arizona’s public transportation infrastructure. Recently, Arizona has taken meaningful steps forward in this area through the construction of the light rail system in Phoenix, plans to install a modern streetcar in Tucson, and long-term aspirations of connecting the metropolises with a high-speed train. In the interest of creating a greener, more efficient, and more desirable transportation infrastructure, Arizona must embrace mass transit. Special categories of liability that target common carriers only serve to inhibit this goal. Adequate levels of safety and redressability in the event of true negligence are still attainable under a traditional negligence scheme. The fact that New York, the state with great reliance on common carriers, has turned away from the common carrier doctrine should alleviate concerns that abandoning the doctrine will lead to a more hazardous public transportation infrastructure.7

Just as the safety of common carriers has changed over the past century, so too should the status of the common carrier doctrine. If formally adopted, the reasonable care standard would provide a consistent, workable framework for assessing common carrier liability as Arizona begins to increase its reliance on public transportation. If, however, the court does not wish to adopt the Lowrey approach, it should at least seize the opportunity to clarify the emerging confusion in the lower courts and issue a clear standard for common carrier liability.


  1. Ariz. Rev. Stat. § 12-2505 (2011). 

  2. See Lowrey v. Montgomery Kone, Inc., 42 P.3d 621, 627 (Ariz. Ct. App. 2002) (“We believe that the time has come to discard the notion that a common carrier bears a higher duty towards its passengers than that of reasonable care under all of the circumstances.”); see also Block v. Meyer, 696 P.2d 1397, 1383–84 (Ariz. Ct. App. 1985) (“We find no error in the trial court’s failure to instruct the jury that a common carrier owes its passengers the highest standard of care practicable, or words to that effect.”). 

  3. Historically, the common carrier doctrine was justified based on the perceived ultra-hazardousness of mass transit, the carrier’s duty to the public, and the passenger’s dependence on the common carrier for its safety. 

  4. 42 P.3d at 626. 

  5. Prosser & Keaton, Torts § 32 173–74 (5th ed. 1984) (“The whole theory of negligence presupposes some uniform standard of behavior… . The standard of conduct which the community demands must be an external and objective one, rather than the individual judgment, good or bad, of the particular actor … .”). 

  6. Lowrey, 42 P.3d at 627. 

  7. See Bethel v. N.Y. City Transit Auth., 703 N.E.2d 1214, 1218 (N.Y. 1998) (rejecting the common carrier doctrine in favor of the reasonable care standard).