(concurring in part and dissenting in part). I concur with that part of the opinion in which the majority concludes that Officer Andrade is entitled to immunity for his discretionary decisions made in relation to his pursuit of Zergoski. However, I write this dissent because I do not agree that the City can be held liable under the facts of this case.
Initially, it should be noted that the majority's conclusions on causation are built upon the foundation of its interpretation of the ministerial duty imposed by Wis. Stat. § 346.03(6). Throughout the opinion, the *332majority makes repeated reference to the statute as mandating that officers consider the severity of the crime "upon initiating or continuing a pursuit." However, the statute contains no language concerning initiating or continuing pursuits. In fact, the statute refers only to providing written guidelines for its officers regarding "exceeding speed limits under the circumstances specified in sub. (4) [to obtain evidence of a speed violation or if responding to a felony in progress call] and when otherwise in pursuit of actual or suspected violators." Wis. Stat. § 346.03(6) (emphasis added). Nothing in the plain language of the statute refers to a point in time that an officer must evaluate certain factors, nor does it impose a mandate that successive reevaluations be conducted at set intervals.1
In particular, it is the section of the opinion on causation that prompts me to write this dissent. The majority concludes that there was credible evidence to support the jury's finding that the City was "causally negligent with respect to its defective pursuit policy." Majority op. at 315. It bases this conclusion on the testimony of Officer Andrade, his supervisor — Buechner, Zergoski, and in large part the plaintiffs expert witness Leonard Territo, who testified that he believed the failure of the City's policy to instruct its officers to consider the nature of the offense *333was a substantial factor in causing Cavanaugh's injuries.
The majority correctly states that this court must uphold a jury's finding of fact if it is supported by any credible evidence or reasonable inferences therefrom. However, "it is impermissible to base a judgment on 'conjecture, unproved assumptions, or mere possibilities.' " Merco Distributing Corp. v. Commercial Police Alarm Co., 84 Wis. 2d 455, 461, 267 N.W.2d 652 (1978) (quoting Schwalbach v. Antigo Electric & Gas, Inc., 27 Wis. 2d 651, 655, 135 N.W.2d 263 (1965)). Further, " 'when the matter remains one of pure speculation or conjecture or the probabilities are at best evenly balanced, it becomes the duty of the court to direct a verdict for the defendant.'" Merco, 84 Wis. 2d at 460 (quoting Prosser, Law of Torts 241 (4th ed. 1971)).
The majority mischaracterizes the causation analysis as hinging on whether Officer Andrade or his supervisor considered the severity of the crime despite the defective policy. Majority op. at 306. On the contrary, determination of cause is based on whether the breach was a substantial factor in causing the injury. I cannot agree with the majority that the credible evidence needed to establish this link was presented.
In order to establish the causal nexus in this case the plaintiff had to present evidence that the breach (the fact that the City's policy did not state that an officer must consider the severity of the crime in deciding whether to exceed the speed limit while pursuing a vehicle) was a substantial factor in causing the injury (Cavanaugh's death). In other words, the plaintiff had the burden to prove that: (1) if the written policy required, officers to consider the severity of the crime, (2) then, Officer Andrade would have terminated the chase, and (3) Zergoski would have slowed down or *334stopped his vehicle before reaching the intersection at 60th and Morgan thereby averting the collision.2
In order to sustain a finding of liability against the City, the court must find sufficient credible evidence in this record to support the conclusion that Officer Andrade would have terminated his pursuit if the written policy had included severity of offense as one of the factors he must consider. Yet, Officer Andrade, well aware of the multiple traffic violations he had observed both before and during the pursuit, testified that he never considered letting the fleeing vehicle simply speed away from him because, in his opinion, public safety (itself, a baseline statutory requirement)3 was *335best served by continuing the pursuit. Officer Andrade testified that he wanted to stay close to Zergoski's vehicle,
to give warning to the public out there that this guy is coming through. People hear sirens out there. I didn't want to call it off at that time because I knew if he shot through any one of those lights right there and I wasn't close enough I knew nobody is going to hear him coming; and, if some innocent citizen were driving there through [sic], they would be hit by him and they wouldn't know it.4
Similarly, supervisor Buechner testified that Zergoski was driving in a dangerous manner and represented a danger to the public. Therefore, although he considered whether Officer Andrade should terminate the pursuit, he decided based on a number of factors, that the pursuit should not be terminated. Further, *336despite the fact that Buechner did not use the exact words "I considered the severity of the offense," he testified that circumstances under which a pursuit could be terminated include: "[w]eather conditions, pedestrians or vehicle conditions, lighting conditions, the nature of the driving by the pursuit vehicle or by the driver of the pursued vehicle, possibly the reason that this person was being pursued."
The plaintiffs expert, Territo testified that in his opinion officers who had been "properly informed" through a "non-defective policy" would have stopped the chase. Further, his opinion that Andrade's failure to terminate the pursuit was a substantial factor in causing the accident was based on his generic theory that removal of the incentive (pursuit) "invariably" leads to cessation of the dangerous driving behavior by one being pursued. Yet, under cross-examination, Ter-rito admitted that his opinion on causation "assumes that Gary Allen Zergoski would have stopped driving recklessly when he noticed that Officer Andrade stopped pursuing him." This assumption is highly speculative, especially in light of the fact that Zergoski was speeding, driving recklessly, and had already run a red light before Officer Andrade began pursuing him.
In analyzing causation, the issue is not what some hypothetical officer would have done, but rather, whether this specific officer would have stopped pursuing Zergoski if the City had included "severity of the crime" in its policy. Although the expert's opinion on what the hypothetical officer would or should do under the facts of this case was clearly relevant to the issue of Andrade's alleged negligence, the majority correctly concludes that Officer Andrade is immune from liability. In determining whether the City can be held liable, we must search the record for evidence of a causal link *337between the City's negligence and Cavanaugh's damages, and not for evidence of Officer Andrade's alleged negligence. In contrast to proof of negligence, which is based on standards of what the hypothetical "reasonable" person would have done under the circumstances, in order to establish causation, we must find credible evidence which can connect the actual conduct that has been found negligent by the specific defendant (here, the City's failure to perform its ministerial duty) to the plaintiffs damages.
An expert's opinion that some hypothetical officer would have chosen not to continue the chase, and therefore the accident would never have happened, does not provide the necessary link between the City's failure to perform its ministerial duty and the damages in this case. Neither can an expert simply opine, as did Territo, that "under the specific fact situation, the City's defective policy was a substantial factor in causing Cavanaugh's injury" and thereby create credible evidence to support his conclusion. There must be credible evidence in the record to support his opinion that if the City had included "severity of the crime" in the list of factors for an officer to consider when deciding to exceed the speed limit in pursuit of actual or suspected violators, Officer Andrade would have decided to let Zergoski get away and that therefore Cavanaugh's damages would not have occurred. There is no such evidence in the record. Cause was never established, and therefore, the City cannot be held liable.
Additionally, I feel that I must address disturbing public policy implications of the majority's opinion.5 *338Under the standard advocated by Territo, and seemingly adopted by the majority, a "non-defective" pursuit policy would require officers to consider severity of offense, not only at the initiation of a pursuit but in an ongoing evaluation of whether to terminate. More importantly, it would encompass a presumption that continuation of pursuit is justified only for major offenses and those involving other violations should be terminated.6
The majority states that "nothing in [its] opinion or in § 346.03(6) creates ... a presumption [that continuing pursuits can only be justified for major offenses]," and that the case is "not about . . . officers being stripped of their discretion.'' Majority op. at 314. Yet the majority relies on Territo's opinions on this very issue [the propriety of termination of pursuit given the specific facts of this case] to establish causation, *339thereby at least implicitly engrafting limitations upon police discretion.
Territo testified that he was not critical of Officer Andrade's decision to initiate pursuit, that in fact, Officer Andrade "would have been derelict in his duty if he had not attempted to stop [Zergoski]The plaintiffs expert based his criticism of Officer Andrade (and of the City's policy) on the officer's failure to terminate the pursuit. Territo testified that if the City's policy included severity of the crime, Andrade and his supervisor would have been informed that a less severe offense, such as a traffic violation, would result in greatly diminished latitude as opposed to chasing a person wanted for murder. I agree with the majority that § 346.03 does not contemplate that an officer's latitude or discretion should be "diminished" during a chase on the sole basis of the severity of offense, but remain concerned that the message conveyed by the majority opinion does just that by affixing liability under the circumstances of this case.
While in pursuit, Officer Andrade knew that the fleeing party had committed several offenses, including speeding, running a red light and stop signs, weaving, "fishtailing" and other indicia of reckless driving, and he suspected drunken driving.7 Additionally, Officer Andrade testified that Zergoski's driving was reckless and in his opinion posed a "risk to the public." If the policy advocated by Territo were adopted, it would seemingly require officers to terminate pursuit of persons whom they know to be driving recklessly, whom they suspect are driving while intoxicated, and whom *340they feel pose a risk to the public. What would happen if an officer applying this policy ceased a pursuit and the fleeing driver continued driving in a dangerous fashion and struck a pedestrian a few blocks later? It would not be at all farfetched to foresee the City finding itself in the position of defending a negligence claim based on failure to protect the public from a known risk.
A policy that requires officers to cease pursuing those who are driving recklessly and speeding would only seem to encourage people bent on eluding the police to persist in such behavior. Rather than making our streets safer, such a policy has the potential to backfire and actually promote dangerous evasive driving.
There is nothing in Wis. Stat. § 346.03(6) that indicates that the legislature intended that officers should be stripped of the discretion to pursue unless they know the fleeing suspect has committed offenses in addition to those observed. As the majority pointed out in its conclusion on the City's negligence, the statute requires that the policy consider the severity of the crime with respect to pursuing at excessive speeds. Nothing in the statute mandates that the City have a policy requiring an officer, after observing highly dangerous driving behavior, to discontinue a chase if the officer thinks that the fleeing driver is unlikely to voluntarily stop. I think this court should be hesitant to judicially impose such restrictions.
For the reasons stated above, I respectfully dissent from that portion of the opinion concluding that the City is causally liable for Cavanaugh's injuries.
*341I am authorized to state that Justice Donald W. Steinmetz and Justice Jon P. Wilcox join in this concurring/dissenting opinion.
The compact and intense framework of a high-speed pursuit which often lasts, as in this case, only 3 to 4 minutes cannot be subjected to a mechanistic requirement which seems to contemplate a programmed review of a fixed checklist of factors. Unlike the timed back-up carried out by my computer, humans do not easily perform complex decision-making in a calculated manner, especially in instances where discretion is needed to react to a constantly changing situation.
Contrary to the majority's suggestion, this dissent does not ignore the standard of causation and create a more onerous one. Majority op. at 310 n.8. Rather, it simply lays out in case specific terms the series of leaps that are necessary to prove a causal relationship between the alleged breach (the City's policy) and the injury. I remain unconvinced that there was credible evidence proving that the "defective policy" was a substantial factor in producing Cavanaugh's death. The abstract concept of causation as presented by the majority remains unproved because no concrete connection is made between the very physical realities of the absence of severity of offense in the guidelines and the automobile collision that took Cavanaugh's life.
Wisconsin Stat. § 346.03(5) reads:
The exemptions granted the operator of an authorized emergency vehicle by this section do not relieve such operator from the duty to drive with due regard under the circumstances for the safety of all persons nor do they protect such operator from the consequences of his or her reckless disregard for the safety of others.
(Emphasis added).
The plaintiff makes no claims that Officer Andrade was reckless in any manner.
The majority recounts Officer Andrade's negative response to the plaintiffs question of whether he believed that the pursuit endangered others "on the road." The quoted language also demonstrates that the officer's belief was based on. the fact that there was no traffic "on the road we were on" at that time. Majority op. at 307-08 n.7.
I disagree with the majority's characterization of this testimony as "contrary" to Officer Andrade's statements that he felt Zergoski's reckless driving posed a risk to the public and that public safety was best served by staying behind the fleeing vehicle with emergency lights and sirens operating. I find nothing incompatible in the officer's belief both that the absence of traffic on that road he and Zergoski were on meant that no one on that road was endangered, and that vehicles (such as Cava-naugh's) on side streets were being put at risk by Zergoski's conduct. Officer Andrade's concern for cross traffic is evident in his testimony (quoted in the text above) and formed a reasonable basis for his decision not to terminate the pursuit.
This court's perceptions of public policy considerations are highly relevant to our decisional process and, in fact, are often determinative. For example, this court commented in a recent decision that even though the jury had found the defendant *338causally negligent, "liability does not necessarily follow. Public policy considerations may preclude liability. Whether public policy considerations should preclude liability in this instance is a question of law which we review de novo." Gould v. American Family Mutual Ins. Co., 198 Wis. 2d 450, 460-61, 543 N.W.2d 282 (1996) (citations omitted). See also Rockweit v. Senecal, 197 Wis. 2d 409, 413, 541 N.W.2d 742 (1995); Bowen v. Lumbermens Mutual Cas. Co., 183 Wis. 2d 627, 655-56, 517 N.W.2d 432 (1994); Nelson v. Davidson, 155 Wis. 2d 674, 679, 456 N.W.2d 343 (1990).
Such a policy completely ignores the fact that in many pursuits, the officer has no way of knowing what offenses a fleeing suspect may have committed. This case provides an apt example, as Officer Andrade testified that on first seeing Zergoski speed through the red light he wondered why "this guy was fleeing so fast .... I thought maybe, possibly, somebody maybe could have been chasing him, maybe he could have hit and ran."
In fact, after Zergoski was captured he was charged with causing great bodily harm by intoxicated use of a vehicle, possession of cocaine, operating after revocation of driving privileges, and fleeing an officer.