OPINION

GEORGE, C.J.

Plaintiff was thrown from the horse on which he was riding after the horse was frightened by loud noises from a nearby garbage truck that was operating in its normal manner. Plaintiff sought recovery for his injuries from defendant garbage company, but the trial court granted summary judgment for defendant. The Court of Appeal reversed, concluding that under the applicable common law authorities and this court's decision in Knight v. Jewett (1992) 3 Cal.4th 296 [ 11 Cal.Rptr.2d 2, 834 P.2d 696] ( Knight), defendant owed a duty to plaintiff to avoid increasing the risk of harm over that inherent in the recreational activity of horseback riding, and that there was a triable issue of fact as to whether defendant had breached that duty.

We conclude that the Court of Appeal erred in reversing the trial court judgment in favor of defendant. As we shall explain, the Court of Appeal's mistaken analysis of, and conclusion on, the duty question posed here rested in part upon the appellate court's misapplication of the common law cases concerning liability for injury caused by fright to horses, and in part upon its misunderstanding of our decision in Knight, supra, 3 Cal.4th 296.

As discussed below, for more than 150 years courts have recognized that a defendant breaches no duty of care merely by operating socially beneficial machinery in a manner that is regular and necessary, even if such ordinary operation happens to frighten a nearby horse and, as a result of the horse's reaction, some injury or damage ensues. This long-standing line of authority establishes that although defendant had a duty to conduct its garbage collection activity in a prudent fashion (and to use due care to avoid making unusual noises unnecessary to accomplish its task), it had no duty to avoid making the regular noises that were a normal incident to its operations merely because of the possibility that these ordinary operations might happen to frighten a horse that was in the vicinity of its truck. Once the scope of defendant's duty of care is properly understood, we believe it is clear that the record in this case discloses no evidence that defendant breached its duty of care to plaintiff and, thus, that the trial court properly entered summary judgment in favor of defendant. Hence, we shall reverse the judgment of the Court of Appeal setting aside the trial court's judgment.

Contrary to what is implied in the Court of Appeal's reasoning, neither Knight nor its progeny established a broad, expansive duty on the part of defendant to avoid increasing the risk of harm to plaintiff over that inherent in the recreational activity of horseback riding — a purported duty that takes no account of the established authority recognizing reasonable limitations on the responsibility of others for the risk of injury arising from the skittishness of horses. Although the decision in Knight clarified the nature and scope of the duty owed by a participant in an active sport to other coparticipants in the sport, and also explained that, in light of the adoption of comparative fault principles, the assumption of risk doctrine completely bars a plaintiff's action only in those instances in which the defendant has not breached any duty of care to the plaintiff, Knight did not purport to establish the parameters of the duty of care owed by all potential defendants to persons who happen to be engaged in a sport or activity at the time they sustain an injury. In this case, in which defendant had no participatory involvement in the activity undertaken by plaintiff, the decision in Knight does not define whatever duty was owed by defendant to plaintiff. As already noted, the nature and scope of defendant's duty in these circumstances is established by the considerable line of authority addressing the question of a defendant's potential liability for injuries resulting from the frightening of a horse.

I

According to declarations and deposition transcripts submitted in support of and in opposition to defendant's motion for summary judgment, at 10:00 a.m. on a Monday in early December 1991, plaintiff Darrell Parsons rode his horse, Poco, on a public bridle path adjacent to the Los Angeles Equestrian Center in the City of Burbank. This portion of the bridle path is about a mile long, and at one point runs parallel to and fewer than 10 feet from a chain link fence, on the other side of which is a parking lot located to the rear of a restaurant.

At the same time that plaintiff rounded a corner and approached this location, a trash collection truck operated by defendant's employee, Efren Ramirez, was in the process of picking up and emptying a large debris bin located next to the fence in the restaurant's parking lot. While the truck stood stationary, Ramirez, from inside the truck's cab, inserted mechanical forks into the trash bin. Plaintiff, in deposition testimony appended to defendant's motion for summary judgment and thereafter lodged with the court by plaintiff, testified as follows: When he was approximately 10 feet from the truck, he noticed his horse look directly at the truck and "begin to tense up." The bin was lifted off the ground, to the height of the truck's windshield. Ramirez began shaking the bin up and down, apparently to settle its contents before taking the bin "all the way up and over" his cab to empty it into the truck bed. Plaintiff saw Ramirez "in the side-view mirror," at which time Ramirez proceeded "to go ahead up with the trash bin and all I heard was — evidently there were bottles and cans in the trash bin and the loudest noise — I can't begin to explain how loud that noise was. [¶] By then my horse is bolting and spinning and bucking and that's when I landed . . . on the concrete." According to plaintiff, "it was a matter of split seconds [from] when I turned onto that trail [until] what happened."

The parties stipulated that both plaintiff and Ramirez knew that horses are susceptible to being frightened, and that Ramirez had known for two years that the restaurant abutted a bridle path frequented by horses and their riders. The record contains no evidence that Ramirez saw plaintiff (or that plaintiff was within Ramirez's view) until after plaintiff was thrown and injured. Indeed, plaintiff's own deposition testimony, noting that he saw Ramirez in the side-view mirror, suggests that plaintiff's horse reacted to the noise and became uncontrollable while plaintiff and his horse were behind defendant's truck.

Plaintiff's complaint for damages alleged, as the basis for defendant's liability, that defendant "negligently operated a trash collection vehicle so as to scare plaintiff's horse, causing plaintiff to be thrown from the horse to the ground and to proximately and legally cause injuries and damages to plaintiff. . . ."

Defendant filed an answer asserting that plaintiff had failed to state a cause of action. Thereafter defendant filed a motion for summary judgment based on ostensibly alternative, but, as explained herein, essentially identical grounds. First, defendant asserted it owed plaintiff no duty to guard against the injuries complained of, citing in support the policy considerations set out in Rowland v. Christian (1968) 69 Cal.2d 108, 112-113 [ 70 Cal.Rptr. 97, 443 P.2d 561, 32 A.L.R.3d 496] and other cases. Second, defendant asserted, plaintiff's recovery was barred under the doctrine of "primary assumption of risk," as set out in our then recent opinions, Knight, supra, 3 Cal.4th 296, and Ford v. Gouin (1992) 3 Cal.4th 339 [ 11 Cal.Rptr.2d 30, 834 P.2d 724, 34 A.L.R.5th 769]. Plaintiff responded that summary judgment should be denied because it could not be determined as a matter of law that defendant breached no duty owed to plaintiff.

The trial court granted defendant's motion for summary judgment. The Court of Appeal reversed, concluding that defendant owed and possibly breached a duty to use care not to frighten horses being ridden on the trail, and that the case thus fell outside the bar of primary assumption of risk. We granted review.

II

A "motion for summary judgment shall be granted if all of the papers submitted show that there is no triable issue as to any material fact and that the moving party is entitled to a judgment as a matter of law. In determining whether the papers show that there is no triable issue as to any material fact the court shall consider all of the evidence set forth in the papers, . . . and all inferences reasonably deducible from the evidence. . . ." (Code Civ. Proc., § 437c, subd. (c).) A defendant "has met his or her burden of showing that a cause of action has no merit if that party has shown that one or more elements of the cause of action, even if not separately pleaded, cannot be established, or that there is a complete defense to that cause of action. Once the defendant . . . has met that burden, the burden shifts to the plaintiff . . . to show that a triable issue of one or more material facts exists as to that cause of action or a defense thereto. . . ." ( Id., subd. ( o)(2).) (1) On review of an order granting or denying summary judgment, we examine the facts presented to the trial court and determine their effect as a matter of law. In this case, defendant asserted, and the trial court found, that plaintiff's evidence failed to establish the "duty" element of plaintiff's cause of action for negligence. Duty, being a question of law, is particularly amenable to resolution by summary judgment. ( Knight, supra, 3 Cal.4th 296, 313.)

(2) We held in Knight, supra, 3 Cal.4th 296, that a participant in an active sport owes only a limited duty of care to coparticipants — a duty to avoid intentional injury or conduct so reckless as to be totally outside the range of ordinary activity involved in the sport. ( Id. at p. 320.) In the course of our discussion, we mentioned that "defendants generally . . . have a duty to use due care not to increase the risks to a participant over and above those inherent in the sport" ( id. at p. 316), and we cited, as an example, the duty of a commercial sporting operator to maintain its premises or equipment so as not to expose its patrons to an increased risk of harm. ( Ibid.)

The Court of Appeal below acknowledged that in the present case, unlike Knight, supra, 3 Cal.4th 296, or the commercial operator example cited in our opinion, defendant and plaintiff had no relationship such as coparticipants in an active sport, or as recreational business operator and patron. The Court of Appeal nevertheless read the above quoted passage of Knight as imposing on defendants, generally, a duty — owed to all persons engaged in a sport or similar activity — not to increase the risks of harm over those inherent in the activity in which the plaintiff happens to be engaged. Moreover, the court asserted, such a duty to riders of horses, in particular, "was specifically recognized" under the common law. The Court of Appeal concluded that defendant owed a duty not to increase the risks to plaintiff over those inherent in the sport of recreational horseback riding, and that the public policy considerations set out in Rowland v. Christian, supra, 69 Cal.2d 108, 113, afforded no basis for declining to impose on defendant this asserted duty.

As described below, we conclude the Court of Appeal's analysis was erroneous, both with regard to the scope of the general common law duty owed to horseback riders, and with respect to the proper interpretation of this court's decision in Knight, supra, 3 Cal.4th 296.

III

A

(3) The present unfortunate encounter falls within a centuries-long continuum of contacts between horses and machinery. Whatever the standards of the leisure classes, as exemplified by the sentiment attributed to Mrs. Patrick Campbell ("My Dear, I don't care what they do, so long as they don't do it in the street and frighten the horses."), the courts long have recognized that the needs of a modern, industrial society often conflict with and generally must prevail over the delicate sensibilities of horses. Well before Poco was spooked by defendant's operation of its loud garbage truck with mechanical fork lifts, his equine ancestors similarly were frightened by shrieking, grinding, and hissing steam locomotives, motorized streetcars, steam rollers, motorcars, and numerous other contraptions of the industrial revolution. The attempts in this history to hold defendants liable for resulting injury to horse or rider were, with exceptions inapplicable here, uniformly rejected. Weighing the social utility of these machines and devices against the likelihood that horses might become frightened by the operation of such objects, the courts developed a remarkably uniform rule, holding that a plaintiff whose horse "shied" or "spooked" and caused damage because of the noise, sight, or odor caused by the defendant's regular and necessary conduct, cannot state a cause of action for negligence, because the defendant in such a case has breached no duty of care.

For example, in Stanton v. Louisville N.R. Co. (1891) 91 Ala. 382 [8 So. 798], the plaintiff waited in his horse and buggy at a railroad crossing while the highway was blocked by a stationary train. A second train approached, emitting steam and noise, which frightened the plaintiff's mare, causing her to break loose and injure herself and damage the buggy. Affirming summary judgment for the defendant, the court observed: "The authority to operate a railroad includes the right to make the noise incident to the movement and working of its engines, as in the escape of steam and the rattling of cars. . . . It is not liable for injuries occasioned by horses, when being driven on the highway, taking fright at noises occasioned by the lawful and reasonable exercise of these rights and duties." ( Id. at p. 799.) The court concluded that because the plaintiff failed to show that the noises or emissions complained of were unusual or unnecessary to the regular operation of trains, the defendant breached no duty of care and could not be held liable. ( Ibid.) Scores of decisions are in accord.

The same general rule has been applied in the decisions concerning injuries caused when horses became frightened by the sight, sounds, and odors of early steam- and gasoline-powered "horseless carriages." In Nason v. West (1900) 31 Misc. 583 [65 N.Y.S. 651], the defendant drove his steam-propelled motor carriage near the plaintiff's horse, which bolted, causing damage to the plaintiff's horse-drawn carriage. The court reversed judgment for the plaintiff on the ground that absent "proof of an unusual amount of vapor escaping at the time of the accident, [or] any amount of noise greater than is ordinarily heard in running a machine of that character" ( id. at p. 653), the plaintiff failed to establish a breach of duty by the defendant. The court explained: "[T]he mere fact that a horse takes fright at some vehicle run by new and improved methods, and smashes things, does not give the injured party a cause of action . . . [¶] . . . in the absence of evidence that, at the particular time complained of, the carriage was operated carelessly." ( Id. at p. 652.) The court concluded by articulating the public policy rationale behind its determination that the defendant had breached no duty of care: "The temporary inconvenience and dangers incident to the introduction of these modern and practical modes of travel upon the highway must be subordinate to the larger and permanent benefits to the general public, resulting from adoption of the improvements which science and inventive skill have perfected." ( Id. at p. 653.)

The courts have applied the same general "no breach of duty" rule (for injury caused by the fright of horses) to the necessary and usual attributes of other beneficial machines or devices. For example, in Simonds v. Maine Telephone Telegraph Co. (1908) 104 Me. 440 [72 A. 175], the defendant telephone company was in the process of erecting poles and stringing telephone wire, and for that purpose placed a large stationary wooden reel of bright telephone cable at the side of a city street. A passing horse bolted at the mere sight of the spooled cable and an accompanying lead pipe and caused injury to its rider. The court observed that the reel and pipe "were of such appearance as would be likely to frighten well-broken horses unaccustomed to them" ( id. at p. 176), but rejected the plaintiff's contention that the mere presence of the reel and pipe on the street established the defendant's liability for his injuries. The court reasoned that because the defendant had the right "to erect and maintain its poles and string on them its wires and cables where it did in the street, the [defendant] had the concomitant right to use suitable appliances therefor and in reasonably needful places. . . . [¶] . . . . To say that well-broken horses, carefully driven, must not be frightened, is to say that no new appliance, however useful, shall be used on or near highways. It is common knowledge that all horses . . . are liable to be frightened by any unaccustomed . . . appearances and noises in unaccustomed situations; that they are susceptible to fright from the most trivial things; that their vagaries are unforeseeable; and that it is practically impossible to guard against them." ( Ibid.) The court concluded: "The reel and the lead pipe being otherwise lawfully where and when they were in the street, the mere fact that they were likely to frighten horses unaccustomed to them did not make their presence there unlawful." ( Id. at p. 177.) Accordingly, the court set aside a verdict for the plaintiff, on the ground that the defendant breached no duty of care. The same conclusions have been reached in other decisions concerning horses frightened by the normal and necessary functioning or appearance of steamrollers and threshers, and by various other socially beneficial acts conducted in a normal and necessary manner.

In each category of case, however, the courts recognized "exceptions" to the general rule of nonliability. It has been held that a defendant breaches a duty of care if (i) the defendant conducts or uses a train, automobile, or other device in a careless or imprudent manner, or causes noises or emissions unnecessary to the regular operation of the machine, (ii) the defendant fails to take reasonable protective actions after it knows that the plaintiff's horse actually has become frightened, (iii) the defendant or its employees conduct its machinery in an unnecessary or malicious fashion designed to cause fright, or (iv) the defendant violates a safety statute designed to protect the class of which the plaintiff is a member.

This court addressed the general common law rule, as well as the first and third described exceptions to that rule, in Hahn v. S.P.R.R. Co. (1877) 51 Cal. 605. In that case the defendant's train was stopped when the plaintiff approached, driving his span of horses harnessed to a wagon. The defendant's engineer "looked at [the plaintiff] and laughed, and then opened the cylinder-cocks," enveloping the plaintiff and his horses in a cloud of steam, and causing the horses to spook and throw the plaintiff. ( Id. at p. 606.) Affirming a jury verdict for the plaintiff, we observed that if the horses had been "frightened by the appearance of the train, or by the ordinary noise of its passage, the plaintiff could [not] recover. [¶] Nor should plaintiff have recovered if the runaway was caused by the blowing off of the steam, if this was necessary in the prudent management of the engine." ( Id. at p. 607.) But on the facts proved at trial, we observed, the defendant was at least negligent, and possibly willful and malicious, in unnecessarily releasing steam into the plaintiff and his team, and hence breached its duty of care to the plaintiff. ( Ibid.)

A panel of this state's Court of Appeal applied the second described exception to the common law rule in Eddy v. Stowe (1919) 43 Cal.App. 789 [ 185 P. 1024]. In that case, the plaintiff was riding his horse on the side of a road when a passing motorcycle frightened the animal. The defendant, approaching in his automobile from a distance of some 200 feet, noticed that the plaintiff's horse was bucking and lunging in fright, but nevertheless proceeded directly toward the plaintiff, striking the frantic horse and causing the plaintiff serious injuries. ( Eddy v. Stowe, supra, 43 Cal.App. at pp. 793-794.) Because the defendant had known of the plaintiff's "perilous position" ( id. at p. 795), but had made no effort to "slow up, stop his machine, or do whatever was reasonably required" under the circumstances, the defendant was held to have breached his duty of care to the plaintiff. ( Id. at pp. 795, 797-798; see also Connolly v. Pre-Mixed Concrete Co. (1957) 49 Cal.2d 483 [ 319 P.2d 343] [reaching same conclusion on similar facts].)

Finally, in Johnson v. City of Santa Monica (1937) 8 Cal.2d 473 [ 66 P.2d 433] — a case that fell within none of the exceptions to the common law rule — we observed that a driver of a moving vehicle has no duty to stop or cease operation merely because he or she sees a horse nearby that is not displaying fright, and hence the defendant, a truck driver, was not liable to plaintiff, whose horse bolted suddenly into the path of the truck. We noted that, unlike Eddy v. Stowe, supra, 43 Cal.App. 789, in the case before us the plaintiff's horse displayed no advance warning of fright, and the defendant, upon noticing the horse's fright, "acted at once and clearly in a manner to meet all obligations cast upon him by the law." ( Johnson v. City of Santa Monica, supra, 8 Cal.2d at p. 475.) We commented: " Certainly it was not incumbent upon [the defendant] to stop his truck merely because a horse and rider were approaching the road on which he was traveling, at least until he observed that the horse had become unmanageable. Any guess as to what he might have done to avoid the accident is in the realm of surmise and conjecture. . . ." ( Ibid., italics added.)

B

(5) As a general rule, each person has a duty to use ordinary care and "is liable for injuries caused by his failure to exercise reasonable care in the circumstances. . . ." ( Rowland v. Christian, supra, 69 Cal.2d 108, 112; Civ. Code, § 1714) Whether a given case falls within an exception to this general rule, or whether a duty of care exists in a given circumstance, "is a question of law to be determined on a case-by-case basis." ( Isaacs v. Huntington Memorial Hospital (1985) 38 Cal.3d 112, 124 [ 211 Cal.Rptr. 356, 695 P.2d 653].)

"`[D]uty' is not an immutable fact of nature `"but only an expression of the sum total of those considerations of policy which lead the law to say that the particular plaintiff is entitled to protection."' ( Dillon v. Legg (1968) 68 Cal.2d 728, 734. . . .)" ( Ballard v. Uribe (1986) 41 Cal.3d 564, 572, fn. 6 [ 224 Cal.Rptr. 664, 715 P.2d 624], italics added.) Some of the considerations that courts have employed in various contexts to determine the existence and scope of duty are: "the foreseeability of harm to the plaintiff, the degree of certainty that the plaintiff suffered injury, the closeness of the connection between the defendant's conduct and the injury suffered, the moral blame attached to the defendant's conduct, the policy of preventing future harm, the extent of the burden to the defendant and consequences to the community of imposing a duty to exercise care with resulting liability for breach, and the availability, cost, and prevalence of insurance for the risk involved. (Cf. Schwartz v. Helms Bakery Ltd. [(1967)] 67 Cal.2d 232, 237, fn. 3 . . .; Wright v. Arcade School Dist. [(1964)] 230 Cal.App.2d 272, 278 [ 40 Cal.Rptr. 812]; Raymond v. Paradise Unified School Dist. [(1963)] 218 Cal.App.2d 1, 8. . . .)" ( Rowland v. Christian, supra, 69 Cal.2d at p. 113.)

In addition, when addressing conduct on the part of a defendant that is "deliberative, and . . . undertaken to promote a chosen goal, . . . [ c] hief among the factors which must be considered is the social value of the interest which the actor is seeking to advance." (Prosser Keeton on Torts (5th ed. 1984) § 31, p. 171, italics added, fn. omitted; Schwartz v. Helms Bakery Limited (1967) 67 Cal.2d 232, 237, fn. 3 [ 60 Cal.Rptr. 510, 430 P.2d 68] [quoting with approval italicized portion of same passage from earlier edition of Prosser Keeton, supra]; see also Wright v. Arcade School Dist. (1964) 230 Cal.App.2d 272, 278 [ 40 Cal.Rptr. 812]; Raymond v. Paradise Unified School Dist. (1963) 218 Cal.App.2d 1, 8 [ 31 Cal.Rptr. 847] [both listing, as the first policy consideration in duty analysis, "[t]he social utility of the activity out of which the injury arises"].)

(4b) The early cases discussed ante, part III.A, rely primarily, and often expressly, on this "social utility" policy consideration in concluding that, in a variety of contexts, a defendant is neither "negligent," nor does it "breach a duty of care," merely by causing a machine to produce noises or emissions that are necessary to the regular operation of the machine and that in turn cause a horse to take fright and produce injury or damage. In other words, the cases stand for the proposition that, as a matter of policy, there shall be no liability for fright to a horse and consequent damages arising therefrom when all that the plaintiff can point to is that a socially beneficial machine or apparatus — steam locomotive, streetcar, automobile, truck, transmission wire, steamroller, etc. — properly was used in the manner for which it was designed. Nothing involved in this social utility analysis has changed to direct a different result. If anything, given the declining relative importance of horses in contemporary society, defendant's position has strengthened.

Plaintiff proposes that defendant might have guarded against his injuries by employing various preventative measures — changing the hours of collection, temporarily "blocking off" the area with warning cones or tape, posting warning signs, providing riders with a schedule of collection times, or a combination of these methods. Like points could be raised with regard to most if not all of the cases discussed ante, part III.A, and yet the courts have declined to impose such conditions on the employment of similarly beneficial machines, because to do so unreasonably would impair the utility of those devices. We find no reason to doubt that defendant's garbage collection activity is a vital public service and a matter of high social utility. (See Lyman v. Village of Potsdam, supra, 127 N.E. 312, 314.) We perceive, and plaintiff offers, no basis for treating defendant's garbage collection truck differently from the various machines and devices discussed ante, part III.A, or for increasing the burden on machine operators over what was considered reasonable in an earlier age, when horse riding was more than a mere recreational activity.

A related policy consideration — the consequences to the community of imposing a duty to guard against the possibility of frightening a horse, with resulting liability for breach — also militates against imposing such a duty. The breadth of the list of noises and things that might scare or spook a horse ("[a]s a general rule a horse will shy at what he is not accustomed to seeing [or hearing]"; Pittsburgh Southern Rw. Co. v. Taylor (1883) 104 Pa. 306, 316) is rivaled only by the range of socially useful activities that may produce such noises and provoke such fright. As defendant observes, the Griffith Park network of trails, on which the injury in this case occurred, covers approximately 43 miles, much of it bordering Interstate Highway 5, U.S. Highway 134, and the neighboring urban and suburban communities of Burbank and Glendale. (Cal. State Horsemen's Assn., California Riding Trails Directory and Manual (1980) p. 47; Hileman's Recreational and Geological Map No. 3, Griffith Park (1986).) Should a homeowner whose property abuts this extensive bridle path (or who has horse-owning neighbors) be obligated to peek over his or her six-foot fence to make sure that no horse is near before starting a power lawn mower? Should he or she be required somehow to keep a constant lookout while mowing the lawn, lest he or she frighten a horse that approaches shortly after lawn mowing begins? Should a homeowner or building contractor be obligated to undertake similar procedures before and during use of chain saws, leaf blowers, or other loud power tools? What about noise from passing cars and trucks on the adjacent highways, or from a picnicker's radio, or from an emergency siren or alarm, or from a jetliner's sonic boom? We conclude that imposing a duty in the present case to guard against fright to a horse might well subject all manner of actors to the same duty and potential liability, with obvious and detrimental consequences stifling to the community.

Contrary to the suggestions of plaintiff and the Court of Appeal below, two of the other considerations set out in Rowland v. Christian, supra, 69 Cal.2d 108, 113, do not compel a conclusion that defendant had a duty to guard against frightening plaintiff's horse.

Plaintiff asserts that because defendant's employee knew that a bridle path abutted the garbage bin and that the collection procedure might frighten a horse, a jury reasonably might conclude plaintiff's injury was "foreseeable." (6) As explained in Ballard v. Uribe, supra, 41 Cal.3d at pages 572-573, footnote 6, however, "a court's task — in determining `duty' — is not to decide whether a particular plaintiff's injury was reasonably foreseeable in light of a particular defendant's conduct, but rather to evaluate more generally whether the category of negligent conduct at issue is sufficiently likely to result in the kind of harm experienced that liability may appropriately be imposed. . . ." (Italics omitted.) In other words, there are numerous circumstances (including the present case) in which a given injury may be "foreseeable" in the fact-specific sense in which we allow juries to consider that question, but contrary to plaintiff's understanding, the "foreseeabilty" examination called for under a duty analysis pursuant to Rowland v. Christian, supra, 69 Cal.2d 108, 113, is a very different and normative inquiry.

Even assuming foreseeability as contemplated in Rowland v. Christian, supra, 69 Cal.2d 108, is established here, "we will not treat the mere presence" of such a finding, "standing alone," as imposing on defendant a duty to guard against injuries to plaintiff. ( Bily v. Arthur Young Co. (1992) 3 Cal.4th 370, 399 [ 11 Cal.Rptr.2d 51, 834 P.2d 745, 48 A.L.R.5th 835].) As we have observed, "social policy must at some point intervene to delimit liability" even for foreseeable injury ( Borer v. American Airlines, Inc. (1977) 19 Cal.3d 441, 446 [ 138 Cal.Rptr. 302, 563 P.2d 858]), and "policy considerations may dictate a cause of action should not be sanctioned no matter how foreseeable the risk." ( Elden v. Sheldon (1988) 46 Cal.3d 267, 274 [ 250 Cal.Rptr. 254, 758 P.2d 582], italics added; see also, e.g., Dillon v. Legg (1968) 68 Cal.2d 728, 739 [ 69 Cal.Rptr. 72, 441 P.2d 912, 29 A.L.R.3d 1316] [in determining presence of duty, foreseeability is of importance "[i]n the absence of `overriding policy considerations'"]; Bily v. Arthur Young Co., supra, 3 Cal.4th at p. 398 ["Even when foreseeability was present, we have on several recent occasions declined [on policy grounds] to allow recovery on a negligence theory."].) (4c) As suggested above, such policy considerations — i.e., the social utility of defendant's conduct, and the consequences to the community of imposing a duty to guard against frightening a horse — override the foreseeability factor in this case.

Nor do we agree that the final general consideration listed in Rowland v. Christian, supra, 69 Cal.2d at page 113 — the availability, cost, and prevalence of insurance for the risk involved — supports a legal conclusion that defendant had a duty to guard against frightening plaintiff's horse. The Court of Appeal below assumed that defendant already carries insurance against the risk that it might strike or spook and thus injure a horse or rider while driving its trucks on a roadway (see Veh. Code, § 21759). From this, the court hypothesized that "[a]dding coverage for injuring a horse or rider on a bridle path would not in all probability result in a significant increase in premiums." Whether or not the Court of Appeal's estimation is accurate as to defendant (there is no evidence to support this speculation), we are not confident that the same may be said as to the myriad other actors (i.e., potential defendants) whose everyday and reasonable conduct might cause similar fright to horses.

Although we reject plaintiff's assertion that defendant owed an expansive duty to guard against frightening horses, we affirm that defendant was obligated to conduct itself in accordance with the limited common law duty articulated ante, at pages 469-470. Specifically, defendant was required to (i) avoid employing its garbage truck in a careless or imprudent manner, or causing noises or emissions unnecessary to the regular operation of that machine; (ii) take reasonable protective actions if its operator knew, in time to take such countermeasures, that plaintiff's horse actually had become frightened by the operation of the truck's mechanical forklifts; and (iii) avoid conducting its machinery in an unnecessary or malicious fashion designed to cause fright.

But under the circumstances here presented, there is no basis on which to conclude that defendant breached the limited duty of care it owed to plaintiff. There is no evidence that defendant operated its garbage truck in anything but the regular and necessary manner of a garbage truck acting like a garbage truck (cf. Harrold v. Rolling J Ranch (1993) 19 Cal.App.4th 578, 589 [ 23 Cal.Rptr.2d 671]). Nor is there evidence that defendant's employee knew, in time to take appropriate countermeasures, that plaintiff's horse actually had become frightened by the operation of the truck's mechanical forklifts, and that the operator thereafter neglected to take reasonable steps to avoid increasing the risk to plaintiff. Nor is there evidence that defendant's employee willfully or maliciously caused plaintiff's horse to become frightened in response to defendant's activity.

Under the governing case law, as well as a consideration of the various factors set out in Rowland v. Christian, supra, 69 Cal. 2d at page 113, we conclude that defendant may not be held liable for properly using its truck in the manner for which it was designed. We thus decline plaintiff's invitation to expand the limited duty of care imposed by the common law with respect to the operation of machinery in the presence of horses.

C

The Court of Appeal found, contrary to our conclusion, that defendant had a common law duty to avoid increasing the risk of harm to plaintiff over that inherent in the activity of recreational horseback riding. For this proposition, the Court of Appeal relied principally upon Eddy v. Stowe, supra, 43 Cal.App. 789, and to a lesser extent upon Connolly v. Pre-Mixed Concrete Co., supra, 49 Cal.2d 483, and Johnson v. City of Santa Monica, supra, 8 Cal.2d 473. These authorities simply apply well-established common law and do not support the conclusion reached by the Court of Appeal.

As explained above, both Eddy v. Stowe, supra, 43 Cal.App. 789, and Connolly v. Pre-Mixed Concrete Co., supra, 49 Cal.2d 483, apply one of the exceptions to the general common law rule of nonliability ( ante, fn. 12) — i.e., when the defendant knows that a horse actually has become frightened by a truck or automobile, but nevertheless fails to take reasonable precautions to avoid increasing the risk of harm to the already endangered horse and rider, there is a breach of duty and liability for negligence. Because there is no evidence in the present case that defendant's operator proceeded in the face of knowledge that plaintiff's horse actually had become frightened, the Court of Appeal's reliance upon these decisions is misplaced. Johnson v. City of Santa Monica, supra, 8 Cal.2d 473, as explained above, directly applies the common law rule that a driver of a moving vehicle has no duty to stop or cease operation merely because he or she sees a horse nearby that is not displaying fright. Johnson v. City of Santa Monica holds that, absent evidence of careless driving, a defendant generally cannot be found liable for damages caused by a frightened horse. (Accord, cases cited ante, fn. 11.) Because there is no evidence of careless operation in the present case, the Court of Appeal's reliance upon Johnson v. City of Santa Monica is misplaced.

IV

Contrary to the Court of Appeal below, we conclude that our decision in Knight, supra, 3 Cal.4th 296, also offers no support for the proposition that defendants generally owe a duty not to increase the risk inherent in whatever activity plaintiffs happen to be pursuing, regardless of the lack of relationship between defendant and plaintiff.

In Knight, supra, 3 Cal.4th 296, the plaintiff sued to recover damages after the defendant injured her during an informal game of touch football. The defendant sought summary judgment on the ground that the plaintiff had assumed the risk of injury by "`impliedly agree[ing] to reduce the duty of care owed to her by defendant.'" ( Id. at p. 301.) In opposition, the plaintiff relied upon authority concluding that the defense of "reasonable implied assumption of the risk" had been eliminated by adoption of comparative fault principles in Li v. Yellow Cab. Co. (1975) 13 Cal.3d 804 [ 119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393] ( Li) ( Knight, supra, 3 Cal.4th at p. 301), and denied that "she impliedly had agreed to reduce the duty of care, owed to her by defendant." ( Id. at p. 302.) The trial court granted summary judgment, and the Court of Appeal affirmed. We granted review to resolve a conflict among the Courts of Appeal as to the proper application of the assumption of risk doctrine in light of Li, supra, 13 Cal.3d 804.

We observed that Li, supra, 13 Cal.3d 804, had abandoned the inequitable "`all-or-nothing'" doctrine of contributory negligence in favor of the more "`logic[al], practical . . ., and fundamental[ly] [just] . . . system under which liability for damage will be borne by those whose negligence caused it in direct proportion to their respective fault.'" ( Knight, supra, 3 Cal.4th at p. 305, quoting Li, supra, 13 Cal.3d at pp. 812-813.) Using Li as our guidepost, we proceeded in Knight, supra, 3 Cal.4th at pages 304-308, to determine which category of assumption of risk cases should be merged into the comparative fault system and which category should not.

We concluded that Li, supra, 13 Cal.3d 804, intended to distinguish "between (1) those instances in which the assumption of risk doctrine embodies a legal conclusion that there is `no duty' on the part of the defendant to protect the plaintiff from a particular risk — the category of assumption of risk that the legal commentators generally refer to as `primary assumption of risk' — and (2) those instances in which the defendant does owe a duty of care to the plaintiff but the plaintiff knowingly encounters a risk of injury caused by the defendant's breach of that duty — what most commentators have termed `secondary assumption of risk.'" ( Knight, supra, 3 Cal.4th at p. 308.)

(7) We summarized the "general conclusions" of a majority of the court as follows: "In cases involving `primary assumption of risk' — where, by virtue of the nature of the activity and the parties' relationship to the activity, the defendant owes no legal duty to protect the plaintiff from the particular risk of harm that caused the injury — the doctrine continues to operate as a complete bar to the plaintiff's recovery. In cases involving `secondary assumption of risk' — where the defendant does owe a duty of care to the plaintiff, but the plaintiff proceeds to encounter a known risk imposed by the defendant's breach of duty — the doctrine is merged into the comparative fault scheme, and the trier of fact, in apportioning the loss resulting from the injury, may consider the relative responsibility of the parties. [¶] Accordingly, in determining the propriety of the trial court's grant of summary judgment in favor of the defendant in this case, our inquiry does not turn on the reasonableness or unreasonableness of plaintiff's conduct. . . . Nor do we focus upon whether there is a factual dispute with regard to whether plaintiff subjectively knew of, and voluntarily chose to encounter, the risk of defendant's conduct, or impliedly consented to relieve or excuse defendant from any duty of care to her. Instead, our resolution of this issue turns on whether, in light of the nature of the sporting activity in which defendant and plaintiff were engaged, defendant's conduct breached a legal duty of care to plaintiff." ( Knight, supra, 3 Cal.4th at pp. 314-315.)

Turning to the question whether there existed evidence that the defendant breached his duty of care, we observed that "the nature of a sport is highly relevant in defining the duty of care owed by the particular defendant." ( Knight, supra, 3 Cal.4th at p. 315.) By way of example, we commented that "[a]lthough defendants generally have no legal duty to eliminate (or protect a plaintiff against) risks inherent in the sport itself, it is well established that defendants generally do have a duty to use due care not to increase the risks to a participant over and above those inherent in the sport. Thus, although a ski resort has no duty to remove moguls from a ski run, it clearly does have a duty to use due care to maintain its towropes in a safe, working condition so as not to expose skiers to an increased risk of harm." ( Id. at pp. 315-316.)

We then surveyed numerous California and out-of-state common law decisions, and concluded that, for reasons of policy, a participant in an active sport has only a limited duty of care with regard to coparticipants. Such an actor "breaches a legal duty of care to other participants — i.e., engages in conduct that properly may subject him or her to financial liability — only if the participant intentionally injures another player or engages in conduct that is so reckless as to be totally outside the range of the ordinary activity involved in the sport." ( Knight, supra, 3 Cal. 4th at p. 320.) Applying that standard of care to the facts before us, we concluded there was no evidence that the defendant breached the limited duty he owed to the plaintiff. Accordingly, we held that the case fell "within the primary assumption of risk doctrine, and thus the trial court properly granted summary judgment in favor of defendant. Because plaintiff's action is barred under the primary assumption of risk doctrine, comparative fault principles do not come into play." ( Knight, supra, 3 Cal. 4th at p. 321.)

(8) Thereafter, in Neighbarger v. Irwin Industries, Inc. (1994) 8 Cal.4th 532 [ 34 Cal.Rptr.2d 630, 882 P.2d 347] ( Neighbarger), we considered application of the so-called "firefighter's rule" to plaintiffs who were "private safety employees," in light of the primary assumption of risk doctrine. We unanimously confirmed that the firefighter's rule and the analogous "police officer's rule" properly are viewed, after Knight, supra, 3 Cal.4th 296, not as concepts separate from "primary assumption of risk," but as examples of "the proper application of the doctrine of assumption of risk, that is, an illustration of when it is appropriate to find that the defendant owes no duty of care." ( Neighbarger, supra, 8 Cal.4th at p. 538.) In so holding, we observed in Neighbarger, that Knight "disapproved earlier cases that applied the [assumption of risk] doctrine as a bar to liability on the basis of [a] plaintiff's subjective, voluntary assumption of a known risk" and that Knight "rejected the theory that a plaintiff implicitly consents to undertake the risk of injury despite the defendant's duty of care." ( Neighbarger, supra, 8 Cal.4th at p. 537.) Under the compulsion of Knight, supra, 3 Cal.4th 296, we overruled aspects of our own prior firefighter's rule cases that were inconsistent with these principles. ( Neighbarger, supra, 8 Cal. 4th at p. 541.)

As noted earlier, the Court of Appeal below focused on our statement in Knight, supra, 3 Cal.4th at page 316, that "defendants generally do have a duty to use due care not to increase the risks to a participant over and above those inherent in the sport." That statement, however, was made in the context of our discussion of the duty owed by parties who have some organized relationship with each other and to a sporting activity — in our example, that of ski resort and ski patron. Nevertheless, the Court of Appeal below seized upon this language as support for a general duty not to increase the risk inherent in whatever sporting or recreational activity a plaintiff happens to be pursuing, regardless of the lack of relationship between the parties.

We did not impose such a general duty in Knight, supra, 3 Cal.4th 296. On the contrary, Knight, consistently with established case law, simply requires courts in each instance to examine the question of duty in light of the nature of the defendant's activities and the relationship of the parties to that activity. ( Knight, supra, 3 Cal.4th at pp. 309, 313, 318; accord, Neighbarger, supra, 8 Cal.4th at p. 541 ["We . . . keep in mind . . . the nature of the defendant's activities and the relationship of the plaintiffs and the defendant to that activity to decide whether, as a matter of public policy, the defendant should owe the plaintiffs a duty of care."].)

As illustrated by Court of Appeal cases decided since Knight, supra, 3 Cal.4th 296, there are circumstances in which the relationship between defendant and plaintiff gives rise to a duty on the part of the defendant to use due care not to increase the risks inherent in the plaintiff's activity. (9) For example, a purveyor of recreational activities owes a duty to a patron not to increase the risks inherent in the activity in which the patron has paid to engage. (See, e.g., Harrold v. Rolling J Ranch, supra, 19 Cal.App.4th 578 [recreational horse riding]; Ferrari v. Grand Canyon Dories (1995) 32 Cal.App.4th 248 [ 38 Cal.Rptr.2d 65] [white water rafting]; Branco v. Kearny Moto Park, Inc. (1995) 37 Cal.App.4th 184 [ 43 Cal.Rptr.2d 392] [motocross course]; Connelly v. Mammoth Mountain Ski Area (1995) 39 Cal.App.4th 8 [ 45 Cal.Rptr.2d 855] [snow skiing].) Likewise, a coach or sport instructor owes a duty to a student not to increase the risks inherent in the learning process undertaken by the student. (See, e.g., Tan v. Goddard (1993) 13 Cal.App.4th 1528 [ 17 Cal.Rptr.2d 89] [horse jockey school]; Galardi v. Seahorse Riding Club (1993) 16 Cal.App.4th 817 [ 20 Cal.Rptr.2d 270] [horse jumping instruction]; Fortier v. Los Rios Community College Dist. (1996) 45 Cal.App.4th 430 [ 52 Cal.Rptr.2d 812] [football class]; Regents of University of California v. Superior Court (1996) 41 Cal.App.4th 1040 [ 48 Cal.Rptr.2d 922] [mountain climbing class].)

(4d) As further illustrated by Court of Appeal cases decided since Knight, supra, 3 Cal.4th 296, however, when, as here, parties have no such (or similar) relationship — and instead are independent actors, separately pursuing their own activities — a defendant generally has no duty to avoid increasing the risks inherent in a plaintiff's activity.

For example, in Romito v. Red Plastic Co. (1995) 38 Cal.App.4th 59 [ 44 Cal.Rptr.2d 834] ( Romito), the family of an electrician who died after accidentally falling on and crashing through a plastic skylight that had been installed years earlier, sued the manufacturer of the skylight for, among other things, negligent design. The defendant moved for summary judgment on the ground, among others, that it neither owed nor breached a duty of care to plaintiffs. The trial court granted the defendant's motion for summary judgment, and the Court of Appeal affirmed.

The court in Romito properly did not focus upon whether the defendant's skylight design had increased the risk inherent in conducting electrical work. Instead, after engaging in a traditional duty inquiry utilizing the policy considerations set out in Rowland v. Christian, supra, 69 Cal.2d 108, 113, the appellate court concluded that although the defendant manufacturer could have used a comparably priced acrylic sufficiently strong to bear the weight of a falling person, for various policy reasons ( Romito, supra, 38 Cal.App.4th at pp. 66-68) the defendant had "no duty of care to protect against the innumerable unforeseeable risks surrounding the accidental misuse of its product." ( Id. at p. 68.)

Similarly, in Lompoc Unified School Dist. v. Superior Court (1993) 20 Cal.App.4th 1688 [ 26 Cal.Rptr.2d 122] ( Lompoc), a bicyclist was struck and injured by an automobile whose driver was distracted by glancing at a football game being played 140 feet away on the defendant school district's property. The trial court denied the school district defendant's motion for summary judgment, and the Court of Appeal, after considering the various factors set out in Rowland v. Christian, supra, 69 Cal.2d 108, 113, reversed, concluding, for reasons of policy (and without considering whether the defendant had increased the risk to the plaintiff over that inherent in bicycling), that there was no evidence that the defendant school district had breached a duty to plaintiff by failing to maintain a "distraction barrier." ( Lompoc, supra, 20 Cal.App.4th at pp. 1692-1698.)

These post- Knight cases confirm that when, as here, no relationship exists between the plaintiff and the defendant, and there is no policy reason for imposing a duty upon the defendant to avoid increasing the risk of harm to the plaintiff over that posed by the activity in which the plaintiff happens to be engaged, the defendant has no such duty. The Court of Appeal below erred in concluding that Knight, supra, 3 Cal.4th 296, suggests otherwise.

V

Vehicle Code, section 21759, imposes a duty on "[t]he driver of any vehicle approaching any . . . ridden animal . . . [to] exercise proper control of his vehicle and . . . [to] reduce speed or stop as may appear necessary or as may be signalled or otherwise requested by any person . . . riding . . . the animal . . . in order to avoid frightening and to safeguard the animal . . . and to insure the safety of any person . . . riding the animal. . . ." (Italics added.) As the Court of Appeal implicitly conceded, no evidence suggests that defendant violated this statute. Defendant's employee was not "driving" the truck at the time of the event, and the truck was not "approaching" plaintiff. Just the opposite: Defendant's truck was stationary as plaintiff approached the rear of the vehicle. Moreover, plaintiff neither signaled, nor otherwise requested, that defendant's employee cease operation of the truck's lifting mechanism. Defendant breached no duty owed under this "right of way" statute.

Plaintiff also insists that a triable issue of fact exists whether defendant violated Los Angeles County Code section 12.08.520(A), which prohibits "operation of the compacting mechanism of any motor vehicle which compacts refuse and which creates, during the compacting cycle, a sound level in excess of 86dBA when measured at 50 feet from any point of the vehicle." (Italics added.) Although defendant appears to assume otherwise, it is highly questionable that there is evidence indicating defendant was using a "compacting mechanism" as that term is employed in the county code. As noted ante, at pages 462-463, plaintiff described his horse's fright as being caused by (i) defendant's insertion of forks into the debris bin, (ii) lifting and shaking of the bin, and (iii) tipping of the contents (including loudly crashing bottles) into defendant's truck. Nowhere in plaintiff's detailed description (or anywhere else in the record before us) is there any reference to employment of a "compacting mechanism."

In any event, assuming that defendant employed a "compacting mechanism" here, the record (as plaintiff concedes) contains no evidence concerning the decibel rating of defendant's truck "during compaction," nor does it reveal whether the truck's supposed "compacting mechanism" exceeded the 86dBA limitation as measured 50 feet from the truck. (Both parties erroneously characterize the county code as prohibiting operation of a "compacting mechanism" at over 86dBA " within" 50 feet of the vehicle.) Although the parties jointly prepared a stipulated list of undisputed facts, and plaintiff filed a separate statement of disputed facts, the decibel rating of the truck (measured from 50 feet or otherwise) during "compaction" (or lifting and shaking of a debris bin) was not addressed in either list submitted to the trial court, and was not considered by that court in its ruling on the motion for summary judgment. In other words, plaintiff presented no evidence that defendant violated Los Angeles County Code section 12.08.520(A). For all these reasons, plaintiff has failed to establish the existence of a triable issue of fact as to whether defendant violated the county code.

VI

The record contains no evidence that defendant breached the limited duty of care it owed to plaintiff. We conclude that the trial court properly entered summary judgment for defendant and, accordingly, we reverse the judgment of the Court of Appeal.

Baxter, J., Chin, J., and Brown, J., concurred.