The opinion of the court was delivered by

FASCIALE, J.A.D.

Defendants South Jersey Transportation Authority (SJTA) and the New Jersey State Police (NJSP) (collectively referred to as "defendants") appeal from a judgment in plaintiff Janet Henebema's favor, entered after a jury trial, and an order denying their motion for a remittitur. Plaintiff cross-appeals from an order denying her request for pre-judgment interest pursuant to Rule 4:58-2(a)(2).1

The parties contested the predicate facts relevant to determining whether defendants either exercised discretionary decisionmaking or performed ministerial acts, a distinction central to applying the correct standard of liability under the New Jersey Tort Claims Act (the Act), N.J.S.A. 59:1-1 to 12-3. The structural question before us is whether a judge or jury resolves that threshold dispute. We hold that when the evidence establishes a genuine issue of material fact regarding whether the alleged failures of a public entity were the result of discretionary decisionmaking as to how to use its resources, or instead involved ministerial acts mandated by law or practice, then that fact issue must be submitted to the jury. The resolution of that factual dispute will guide the jury in applying either ordinary negligence law or the Act's "palpably unreasonable" standard. N.J.S.A. 59:2-3(d). Because the judge himself settled that fact-laden dispute here and charged a potentially erroneous standard of care, we reverse the judgment on liability and remand for a new trial. We affirm in all other aspects.

I.

On December 4, 2005, between approximately 3:05 a.m. and 4:28 a.m., at least eight accidents occurred on the Atlantic City Expressway (the Expressway). Plaintiff's right leg was severed as a result of an accident that occurred near milepost 7.3. Four NJSP troopers were on duty that morning patrolling approximately a forty-four mile length on the Expressway. Troopers Christopher J. DeAngelis and James A. Clay patrolled in one police vehicle, and Troopers Bernard Tennant and Rod Nicholson patrolled in the other. According to an SJTA witness who testified at trial, no adverse weather conditions had been forecasted for the night in question. The morning, however, turned out to be hectic and chaotic due to unexpected poor weather conditions and the numerous accidents.

The first of several 9-1-1 calls to SJTA dispatch operators reporting four accidents at the scene where plaintiff was injured was made at 3:55 a.m. by Joshua Cooper, after he was involved in a single-car accident at milepost 7.3. Cooper reported that no injuries were suffered, "but [that] the car is kind of in a really bad spot [and] we can't move it." Cooper added that "[t]he car [is] sitting on the left, not moving."

Dispatcher Jeremiah Conner, of the SJTA, took Cooper's call and inquired whether Cooper hit a guardrail. Cooper responded, "No, hydroplaned on the snowy ice." Conner then asked, "[are] you[] in a bad ... location?" Cooper replied: "Well yeah, [we are] like on the left, like right up like we slammed into the middle section thingy.... It happened in the left lane so we need to get it out of here." Conner ended the conversation by saying, "Ok[,] we'll get somebody out there[,] alright?" The transcript of that call includes several "[i]naudible" references, and includes the statement, "7 eastbound hit the guardrail[,] no injuries[,] it's in the left lane." In the same call, the dispatcher referred to another accident at milepost 16.2 west with one vehicle off the road.

At approximately 4:18 a.m., Conner received a call from Atlantic Cape MedCom.2 The caller informed Conner that her supervisor at MedCom had just reported a subsequent two-car motor vehicle accident "at the 7 south exit." Conner responded, "Yes[,] we have that [and] we're getting somebody out there[,] we just have a lot of accidents right now."

At 4:22 a.m., Conner dispatched Cooper's call to the NJSP. Dispatch operator John Travis, who was also on duty that morning, testified that there was no dispatch call indicating that they were now also dealing with a two-car accident at milepost 7.3.

When Cooper's 3:55 a.m. call came in, one call was already "stacked," or piled up, because the four patrolling troopers were diverted to other accident locations. For example, at around 3:05 a.m., Troopers DeAngelis and Clay responded to an accident at milepost 26 and remained at that site until approximately 4:00 a.m., whereupon they proceeded further west to handle an earlier non-emergency call. Around the same time, Troopers Tennant and Nicholson responded to a vehicle accident at milepost 16.2 involving one fatality. While the troopers were at those accident scenes, four additional accidents occurred in succession at milepost 7.3 in the westbound lanes, one of which involved plaintiff.

Milepost 7.3 has a gradual incline that passes over the Garden State Parkway. A driver must reach the crest of the incline before the other side of the Expressway is visible. The four accidents occurred about 350 feet beyond the crest on an allegedly icy road surface. We discern the following facts regarding these four accidents, mindful that the disputed aspects of those facts will be relitigated at a new trial.

The first accident occurred at approximately 3:55 a.m. and involved the Cooper vehicle. Cooper traveled at approximately fifty-five to sixty miles per hour, reached the unsafe road surface, and lost control of his vehicle. His vehicle slammed into the Expressway's concrete median barrier and came to rest facing east at least partially in the far left westbound lane. Cooper activated his high beam lights, he and his passengers exited the vehicle, and they ran to the side of the Expressway. The troopers were unable to respond to Cooper's 9-1-1 call because they were at other accident scenes.

Approximately ten to fifteen minutes later, a second one-car accident occurred involving a vehicle driven by Michael R. Testa. Like Cooper, Testa approached milepost 7.3 and lost control of his vehicle, which stopped horizontally across the middle and left lanes of the three-lane westbound Expressway. Testa and his passenger exited his disabled vehicle and then Testa called 9-1-1. The troopers remained unable to respond due to other accidents.

Other drivers traveling westbound on the Expressway reached Cooper and Testa's disabled vehicles and successfully passed them using the right lane. An ambulance driver then happened on the scene, stopped in the middle lane, and activated the ambulance's emergency lights. Other drivers managed to pass the ambulance and disabled vehicles using the right lane. Before another accident occurred at the scene, defendants rejected emergency assistance that the Egg Harbor Township Police Department (Egg Harbor PD) offered to the NJSP.

A third accident then occurred at approximately 4:25 a.m. involving plaintiff's vehicle. Plaintiff was traveling in the middle lane, observed the flashing lights, and attempted to pass the ambulance on its left. Plaintiff's vehicle then collided with Testa's vehicle. Because her driver-side door was wedged against the concrete barrier, plaintiff exited from her passenger-side door and then stood on the Expressway.

A few minutes later, the fourth accident occurred, tragically injuring plaintiff. Domenico Raddi, Jr., approached milepost 7.3 at approximately fifty-five to sixty miles per hour, and his vehicle struck plaintiff's car and plaintiff while she was standing on the Expressway. The fourth accident occurred before troopers arrived at the scene. The computer-assisted dispatch (CAD) system data showed that the first police officer arrived at the scene at approximately 4:43 a.m., fifty minutes after the Cooper accident.

As noted, there were numerous calls coming in reporting accidents along other areas of the Expessway as well. There were three SJTA dispatchers on duty that morning, including Conner, Travis, and a supervisor, handling approximately eighty-eight transmissions during the relevant time period. As is the usual procedure, SJTA dispatch operators receive 9-1-1 calls, obtain information from the callers, enter it into the CAD, and then broadcast that information to the troopers on duty.

According to New Jersey Standard Operating Procedure F41 (SOP 41):

SOP 41 further required that troopers dispatched to the site of an emergency "respond to the scene of the crime, accident, or other incident, without delay, as quickly as possible, by the most direct means."

SOP 41 also classified calls for assistance/service in terms of priority:

I. Emergency Calls for Assistance/Service

II. Non-Emergency Calls for Assistance/Service

At trial, there was a difference of opinion as to the nature and import of SOP 41. James Aaron Williams, plaintiff's expert in the field of law enforcement policies, practice, and dispatch training procedures, testified that where those procedures indicated "shall" or "will," there was "no discretion, and it's already been thought out and you simply do it," and weather conditions did not change those commands.3 "The dispatch service is required and mandated to put out over the airwaves all the information that they receive" from incoming calls "immediately," and "particularly emergency calls." The dispatchers must ask about and convey all information about injuries, and about "hazardous conditions on the roadway, such as cars being stranded on the highway, trucks blocking the passageway, vehicles facing the wrong way in one-way traffic[,] and things of that nature."

According to SOP 41, section III, "Dispatching Calls for Assistance," the dispatcher must constantly dispatch to the troopers to "keep ... him or her constantly updated on the traffic conditions." The dispatchers must also update the troopers if additional information comes in while troopers are responding to a call; "the police officers on the road receive their information and updates in an immediate fashion from the dispatcher." Williams further opined that dispatchers did not have the discretion to decide which calls are fit calls to broadcast; they must dispatch everything when they get it.

Williams conceded, however, that there was no written requirement that duplicative calls must be broadcast. He also acknowledged that the decision to split troopers into separate cars involved a discretionary judgment and that a portion of SOP 41 (section II, subsection b) was a "guide." Indeed, SOP 41 is labeled as a "guideline."

Travis agreed that the troopers were doubled up in units after midnight, and it was within the shift commander's discretion to allow them to be split up into separate cars. Travis also testified that tow trucks would not be sent to a location before a trooper could arrive if the incident involved an accident that required a trooper's investigation before a vehicle should be moved.

Sergeant Karl Kramer of the SJTA, who supervised the dispatch operators on the morning of the accidents, concurred that as to "mutual aid, whether or not to call the locals for assistance, whether or not to split troopers after midnight, [and] towing procedures," were "all discretionary on the trooper," and informed by the trooper's training and experience. At 4:10 a.m., Egg Harbor PD called the SJTA and offered assistance to the troopers. Sergeant Kramer asked the dispatch operators what they usually do when a local police department offers to assist them, and Dispatch Operator Robert Buccilli indicated that they usually first accept police assistance from the nearby airport. The sergeant then declined the mutual aid from Egg Harbor PD and called for police assistance from the airport. In doing so, he allegedly followed the SJTA unwritten procedure. The sergeant also requested that additional troopers from the next shift arrive early to assist the troopers on duty.

As to mutual aid, Robin McKaig, the SJTA communications superintendent, did not know of any written procedures of the SJTA for handling mutual aid requests. SOP 41 is silent on this matter. According to McKaig, the local police generally would not be called upon to assist when more help was needed; the SJTA would usually first seek help from other State Police troopers barracks, from Belmar, Buena, the airport located at milepost 9, or the Garden State Parkway. Even Williams, plaintiff's expert, agreed that the SJTA's practice was to call the airport or other State Police barracks when they had emergency needs, or to call in troopers from other shifts.

Furthermore, Jeffrey Anderson, a Sergeant First Class trooper, who was the Assistant Station Commander at the Expressway (the highest filled position at that post), explained that State Police policies statewide did not have any written SOP, nor any verbal policy or procedure, regarding mutual aid. If additional assistance was needed, the midnight shift troopers would break up into two cars, or troopers would be called in from another shift or another station. Anderson would not call in local police officers as first responders, "especially on a road like the Expressway" because "there are too many things that can go wrong" particularly because the police radios were incompatible so communications would only be possible by going through the third-party dispatchers.

As to the dispatcher's duty to dispatch that the milepost 7.3 accident was a priority, McKaig explained that when a call came in, a dispatcher was responsible to gather "[a]s much information as they possibly can" and "as fast as they can before the next call comes in." According to McKaig, a dispatcher then dispatched the information to the State Police, maintenance personnel, or animal control officers. If multiple calls came in regarding the same incident, the first would be dispatched, but "[w]e don't continually dispatch the same call out over and over and over again."

With respect to the execution of the dispatcher's duty in the instant matter, Travis testified that "[i]t would be hard to determine" what priority he would have given to Cooper's call:

While agreeing that Cooper's accident created "a traffic hazard," Travis indicated that Conner's approach was correct, to convey all of the information to the troopers and "[w]hether they handled it as a nonemergent or emergent, [is] up to them." Travis further explained that if troopers are not available to address a call, the sergeant at the desk is made aware that calls are being stacked. Then, if a trooper cleared work on a particular accident and others were stacked, the dispatcher would advise the trooper about the outstanding matters, indicating the priority matter. If all the stacked items seemed to have the same priority level, they would all be conveyed and the trooper could advise which call would be addressed next.

In March 2007, plaintiff filed her complaint against defendants seeking compensation for her pain and suffering and economic losses.4 In October 2009, plaintiff filed a $5,000,000 offer of judgment against defendants, pursuant to Rule 4:58-1. Defendants rejected plaintiff's offer and the matter proceeded to trial.

The judge conducted a jury trial on fourteen days between September 2010 and October 2010. Plaintiff contended during trial that defendants failed to (1) accept the mutual aid offered by the Egg Harbor PD; (2) split up the troopers into four police cars; (3) dispatch troopers properly; and (4) dispatch tow trucks timely. The judge determined that these alleged lapses involved ministerial acts which defendants were mandated to perform and therefore charged the jury solely on ordinary negligence principles. Although the parties sharply disagreed on the predicate facts regarding whether defendants' actions were discretionary or ministerial, and even though the judge himself recognized that some of defendants' conduct was discretionary in nature, the judge did not submit the factual dispute to the jury.5

The jury returned a verdict, apportioned twenty percent negligence on the NJSP and eighty percent on the SJTA, and awarded plaintiff $8,748,311.6 Defendants then filed a motion for a judgment notwithstanding the verdict, or in the alternative, for a remittitur or new trial. Plaintiff filed a cross-motion and sought pre-judgment interest pursuant to Rule 4:58-2(a)(2). The judge denied the motions, rendered a written decision, and entered the judgment.

On appeal, defendants argue that the judge erred by (1) failing to charge the jury on the palpably unreasonable standard required by N.J.S.A. 59:2-3(d); (2) allowing Williams to render a net opinion; (3) permitting plaintiff to submit surprise rebuttal evidence regarding mutual aid; and (4) denying their motion for a remittitur. On her cross-appeal, plaintiff contends that the judge erred by denying her motion for pre-judgment interest.

II.

We begin by addressing defendants' argument that the judge issued a flawed jury charge. They maintain that the decision to charge ordinary negligence or a palpably unreasonable standard requires that the jury first resolve the predicate factual dispute that involved whether defendants had the discretion, pursuant to N.J.S.A. 59:2-3(d), to determine "how to utilize or apply their existing resources." They contend that the judge "usurp[ed] the jury's function in deciding whether the [nature of the predicate] acts [by defendants] were ministerial or discretionary." Defendants assert that the failure to resolve these predicate facts correctly deprived the jury of applying the appropriate standard. of care and caused ambiguity in the soundness of the verdict because it is not known whether the jury found defendants negligent for ministerial or discretionary conduct.

A.

The standard of review for jury charges is well-established. "It is axiomatic that clear and correct jury charges are essential to a fair trial...." Das v. Thani, 171 N.J. 518, 527, 795 A.2d 876 (2002). Courts should correctly explain the controlling law in clear and understandable language. Carmona v. Resorts Int'l Hotel, Inc., 189 N.J. 354, 374, 915 A.2d 518 (2007); Velazquez v. Portadin, 163 N.J. 677, 688, 751 A.2d 102 (2000).

Incorrect jury instructions "are poor candidates for rehabilitation as harmless," and generally are presumed to constitute reversible error. Das, supra, 171 N.J. at 527, 795 A.2d 876 (internal quotation marks omitted). In making that assessment, we must consider the jury charge as a whole. Mogull v. CB Commercial Real Estate Grp., Inc., 162 N.J. 449, 464, 744 A.2d 1186, cert. denied, 165 N.J. 607, 762 A.2d 221 (2000). Having done so here, we concur with defendants that the jury instructions on liability were fundamentally deficient.

B.

Under certain circumstances, public entities are entitled to immunity pursuant to the Act. The New Jersey Legislature declared that "public entities shall only be liable for their negligence within the limitations of [the Act]." N.J.S.A. 59:1-2. By establishing this public policy, the Legislature recognized that "government should not have the duty to do everything that might be done." Ibid. Immunity, therefore, is the general rule under the Act, and liability is the exception. Coyne v. Dep't of Transp., 182 N.J. 481, 488, 867 A.2d 1159 (2005). "[T]he burden is on the public entity both to plead and prove its immunity under our Act...." Kolitch v. Lindedahl, 100 N.J. 485, 497, A.2d 183 (1985).

Pertinent to our discussion regarding whether the judge erred by charging only ordinary negligence standards is the distinction made in the Act between discretionary and ministerial functions performed by a public entity. N.J.S.A. 59:2-3(d) provides that

We stated in Del Tufo v. Township of Old Bridge, 278 N.J.Super. 312, 324-25, 650 A.2d 1044 (App.Div.1995), aff'd on other grounds, 147 N.J. 90, 685 A.2d 1267 (1996), that

"[F]or a public entity to have acted or failed to act in a manner that is palpably unreasonable, `it must be manifest and obvious that no prudent person would approve of its course of action or inaction.'" Kolitch, supra, 100 N.J. at 493, 497 A.2d 183 (quoting Polyard v. Terry, 148 N.J.Super. 202, 216, 372 A.2d 378 (Law Div.1977), rev'd on other grounds, 160 N.J.Super. 497, 390 A.2d 653 (App.Div.1978), aff'd o.b., 79 N.J. 547, 401 A.2d 532 (1979), overruled in part on other grounds, Cartel Capital Corp. v. Fireco of N.J., 81 N.J. 548, 410 A.2d 674 (1980)). Put another way, "the term implies behavior that is patently unacceptable under any given circumstance." Ibid.

An act is "ministerial" if it is "`one which a person performs in a given state of facts in a prescribed manner in obedience to the mandate of legal authority, without regard to or the exercise of his [or her] own judgment upon the propriety of the act being done.'" Morey v. Palmer, 232 N.J.Super. 144, 151, 556 A.2d 811 (App.Div.1989) (quoting Black's Law Dictionary, 1148 (4th ed.1968)).

Thus, immunity under the Act exists for discretionary activities unless a public entity's actions were palpably unreasonable. And ordinary negligence principles apply for a public entity's performance of ministerial functions. "`Palpably unreasonable' means more than ordinary negligence, and imposes a steep burden on a plaintiff." Coyne, supra, 182 N.J. at 493, 867 A.2d 1159.

C.

We now turn to defendants' contention that the judge "usurp[ed] the jury's function in deciding whether the [nature of the predicate] acts in question were ministerial or discretionary."

As noted, the parties aggressively disputed whether defendants lacked discretion to accept mutual aid, split up the troopers, and timely dispatch troopers and tow trucks. For example, defendants introduced evidence that showed they exercised discretion whether to accept mutual aid. Egg Harbor PD called the SJTA and offered assistance to the troopers. Sergeant Kramer asked the dispatch operators what they usually do when a local police department offers to assist them, and Dispatcher Buccilli indicated that they usually first accept police assistance from the nearby airport. Sergeant Kramer then declined the mutual aid from Egg Harbor PD and called for police assistance from the airport. In doing so, he allegedly followed the SJTA unwritten procedure. The sergeant also requested that additional troopers from the next shift arrive early to assist the troopers on duty. Thus, there is evidence from which the jury could reasonably find that defendants "exercis[ed] personal deliberations and judgment," and he examined "the facts, reach[ed] reasoned conclusions, and act[ed] on [those facts] in a way not specifically directed." Kolitch, supra, 100 N.J. at 495, 497 A.2d 183. Of course, if the jury were to find as such, then the jury would have to go on to decide whether the declination of mutual aid amounted to a palpably unreasonable determination.

Likewise, defendants introduced evidence that they exercised discretion as to whether to split up the troopers. Sergeant Kramer testified that the unwritten policy of the NJSP is not to split up troopers after midnight when it snows. He testified that

Plaintiffs expert Williams offered conflicting proof regarding SOP 41. Williams opined that defendants' SOP 41 required them to accept mutual aid and split up the troopers. Williams indicated that SOP 41, and other industry standards, mandated that defendants "seek assistance from other [police] departments." Thus, he disagreed with Kramer's testimony that defendants had the discretion to decline mutual aid.

Williams also testified that "it is the duty and responsibility to immediately get the personnel out with red lights, whatever material markings, signs that are available to the [SJTA] to redirect traffic and for the [NJSP] to, in effect, close down the road." He concluded that forty-one minutes is "totally inadequate and ... not in a timely manner, not dispatched in the manner that the rules and regulations call for."

Yet, despite the conflicting evidence regarding whether defendants had the discretion to determine, in the face of competing demands, how to apply their existing resources, the judge decided the issue instead of submitting it to the jury. We have previously addressed in dicta the need to submit to a jury disputed predicate facts regarding the discretionary or ministerial nature of a public entity's actions. In Del Tufo, supra, 278 N.J.Super. at 315-16, 650 A.2d 1044, a man died while he was in police custody. executor argued that the death occurred because the police allegedly "failed to summon emergency medical assistance for [the decedent] promptly after they arrested him." Id. at 315, 650 A.2d 1044. Rather, the police waited to call the first aid squad until approximately thirty minutes later. Id. at 315-16, 650 A.2d 1044. In concluding that N.J.S.A. 59:3-2(d) was inapplicable, we stated that

Here, by contrast, the record contains evidence that defendants "consciously considered" the action they took that night in light of conflicting or competing demands where resources were obviously pushed to the limit. This is especially so with regard to whether to split up the troopers and accept mutual aid. Resolution of whether defendants' decision was, in fact, discretionary or ministerial requires submission to the jury.

Other than the intimation in Del Tufo, supra, our research has not disclosed any cases in New Jersey directly on point. We have located cases from other jurisdictions, however, that provide persuasive support that disputed predicate facts regarding the discretionary or ministerial nature of a public entity's actions must be submitted to the jury. See Glass v. Gates, 311 Ga.App. 563, 716 S.E.2d 611, 622 (2011) (indicating that, in the context of determining whether a corrections officer performed a ministerial or discretionary act, the disputed predicate facts of whether the County had an unwritten departmental policy imposing a ministerial duty required submission to a jury), aff'd on other grounds, 291 Ga. 350, 729 S.E.2d 361 (2012); Thompson v. City of Minneapolis, 707 N.W.2d 669, 675 (Minn.2006) (stating that "in the context of qualified immunity, a case should be submitted to the jury when the facts giving rise to the applicability of qualified immunity were disputed" (internal quotation marks omitted)). In Thompson, supra, 707 A.W:2d at 675 (quoting Ludivig v. Anderson, 54 FM 465, 474 (8th Cir.), reh'g denied en banc, (1995)), the court stated that

Thus, when the parties dispute the predicate facts necessary for deciding whether the conduct of a public entity was discretionary or ministerial conduct, as in this case, that dispute requires submission to the jury.

D.

We also agree with defendants that the failure to distinguish, in the final charge and on the verdict sheet, the predicate facts tending to show either ministerial or discretionary acts created uncertainty regarding whether the jury found defendants negligent for ministerial or discretionary conduct. The parties sharply contested whether SOP 41, or other industry standards, mandated action or allowed discretion. The verdict sheet and final instructions do not reflect that the jury resolved that factual dispute.

If, in the new liability trial, the jury determines that defendants had the discretion to determine, in the face of competing demands, whether and how to apply their existing resources, the jury would then be required to find whether that determination was palpably unreasonable. "Whether the conduct of the public entity or entities was `palpably unreasonable' under all of the circumstances is a question for jury determination." Paternoster v. N.J. Dep't of Transp., 190 N.J.Super. 11, 20, 461 A.2d 759 (App.Div.), cert. denied, 96 N.J. 258, 475 A.2d 564 (1983). If, on the other hand, the jury determines that defendants had no discretion and were obligated, for example, to accept mutual aid and split up the troopers, then the jury would evaluate defendants' liability exposure using ordinary negligence principles. The final jury charge and verdict sheet must be tailored accordingly at the new trial.

We anticipate that the jury verdict sheet will contain questions for each disputed predicate fact where the record shows that defendants consciously considered whether to exercise discretion on how to utilize their resources. If the jury finds that the decision to decline mutual aid, for example, was discretionary, then they must determine, in accordance with the final charge, whether defendants' determination was palpably unreasonable. On the other hand, if they find that it was a ministerial act, then they must determine whether defendants acted negligently. The same applies to the other disputed predicate facts if the record shows that defendants consciously considered how to allocate their resources. By tailoring the verdict sheet to fit the facts at the new liability trial, any uncertainty regarding whether the jury found defendants negligent for discretionary decisions will be removed.

III.

We now turn to defendants' net opinion argument. Williams opined that "the SJTA and Sergeant Kramer were required to accept and seek out mutual aid." Defendants assert that "the sole purported basis for his opinion was SOP 41." They maintain that Williams rendered a net opinion because SOP 41 does not use the words "mutual aid," nor is that concept addressed or implied. We apply a "deferential approach to a trial court's decision to admit expert testimony, reviewing it against an abuse of discretion standard." Poynerantz Paper Corp. v. New Cmty. Corp., 207 N.J. 344, 371, 25 AM 221 (2011). Against that standard, we see no abuse.

At the outset, we note it was improper for Williams to opine, without the use of a limiting instruction, that defendants were "duty bound" or required by SOP 41 to accept mutual aid. The predicate disputed fact was whether defendants had the discretion to decline mutual aid from Egg Harbor PD, and, if so, whether defendants did so by allocating existing resources in the face of competing demands. A limiting instruction would be warranted at a new trial because "public entities shall only be liable for their negligence within the limitations of [the Act]," N.J.S.A. 59:1-2, rather than by opinion testimony of an expert. See, e.g.. Townsend V. Pierre, 429 N.J.Super. 522, 525, 60 A.3d 800 (App.Div.2013) (approving the use of a limiting instruction to assist the jury's consideration of an expert's opinion).

Nevertheless, we conclude that the omission of any discussion of mutual aid in SOP 41 does not, in and of itself, render Williams' opinion a net opinion. A net opinion is "an expert's bare opinion that has no support in factual evidence or similar data." Pomerantz, supra, 207 N.J. at 372, 25 A.3d 221. "[A] court must ensure that the proffered expert does not offer a mere net opinion." Ibid. In general, an expert should provide the "why and wherefore" supporting his or her analysis. Ibid. Here, Williams did just that.

To be sure, Williams testified that SOP 41 required defendants to accept the mutual aid, thereby implying that they were without discretion to decline it. However, he did not limit the basis of his opinion solely to SOP 41. He testified that

He referred, therefore, to "standard and accepted dispatch procedures," not just SOP 41. In addressing applicable unwritten industry standards regarding mutual aid, he testified that

Plaintiff had data showing that Egg Harbor PD rendered mutual aid to the NJSP previously, and Williams testified that "[i]t's accepted procedure and policy" to accept mutual aid with other police departments, such as Atlantic City. Moreover, he testified that mutual aid "is a common practice for police agencies" to "call upon each other out of necessity in emergency situations." Thus, Williams based his opinion that the NJSP customarily accept mutual aid from local police departments on his interpretation of SOP 41, accepted police industry standards and procedures, and the actual practice of accepting mutual aid employed by the NJSP. Therefore, admission of his testimony was not error.

IV.

Defendants contend that the judge erred in denying their motion for remittitur. They argue that the verdict is "wide of the mark" compared to "what other plaintiffs have recovered in similar cases." We are not persuaded by these contentions.

A.

Justice Hoens explained in Ming Yu He v. Miller, 207 N.J. 230, 248, 24 A.2d 251 (2011), that

Remittitur is an alternative to ordering a new trial, ibid., and the power to order a new trial is "limited," id at 249, 24 A.3d 251 (quoting Carey v. Lovett, 132 N.J. 44, 46, 622 A.2d 1279 (1993)). Here, defendants' argument on appeal is not that the judge failed to order a new trial on damages; rather, they contend that the judge erred by denying their motion for remittitur.8 Thus, we focus on whether the "jury's award ... is `so disproportionate to the injury and resulting disability as to shock the conscience and [convince the court] that to sustain the award would be manifestly unjust.'" Ibid, (quoting Baxter v. Fairmont Food Co., 74 N.J. 588, 604, 379 A.2d 225 (1977)).

Plaintiff was thirty-two years old when the accident occurred, and she had three children, ages one, seven, and ten. Her right leg below the knee was severed at the scene of the accident, and she then required amputation above the knee. Thereafter, she underwent between five and six operations for skin grafting, irrigation, and debridement, and reconstruction of her pelvis necessitating the insertion of a metal plate and screws. She sustained an ankle fracture requiring a brace and physical therapy, shoulder tendonitis, and pain and bone bruising on her left knee. She required outpatient surgery to remove three shards of glass from her forehead, which left her with visible scarring on her forehead. She developed carpal tunnel syndrome from using a walker and crutches in the sixteen to seventeen months after the accident. She suffered from excessive bone growth causing pain at the amputation site when she wore a prosthesis. Her pain and suffering directly affected her attempts to return to work as a casino dealer.

After the accident, plaintiff became pregnant and returned to her orthopedic surgeon, where she complained of increased pelvic pain. X-rays showed additional bone growth at the amputation site necessitating more surgery after she delivered the baby. Plaintiff then underwent carpal tunnel surgery on her left hand after the pregnancy, and her doctor indicated that she would need the same procedure on her right hand.

Valerie Parisi, plaintiffs certified lifecare planner, testified that plaintiffs rehabilitative care needs would cost $2,632,944.89 if she lived at home up to age sbcty-five, and an additional $2,695,222.49 if she received assisted living thereafter. Her vocational and economic expert, Robert Wolf, explained that plaintiff worked full-time as a casino dealer earning just over $59,000 per year, which he annualized to $63,684. She did not return to work until approximately one year after the accident, and then she worked on a part-time schedule. Wolf calculated that she suffered wage losses of $310,949 plus a present value of $107,149 for the value of her domestic household services, for a total economic loss of $418,098.

Plaintiff, her husband, and older brother and sister testified regarding her life activities before and after the accident. Before the accident, she was able to, among other things, play with her daughter, kick the bah around with her nephew, ride a bike, dance, paint, cook, do laundry, and work full-time. After the accident, she was unable to do any of these things.

The judge concluded that the $8,748,311 verdict was proper and not based on bias, prejudice, or sympathy. We give deference to the judge's "feel of the case," Ming Yu He, supra, 207 N.J. at 255, 24 A.3d 251 "`with regard to the assessment of intangibles,'" ibid, (quoting Jastram v. Kruse, 197 N.J. 216, 230, 962 A.2d 503 (2008)). The judge explained that the jury reduced Wolfs number of $418,098, for plaintiffs total economic damages, to $350,000. The jury also rejected Parisi's projection, for expenses for future medical treatment, to $2,247,980.50. The judge stated that the $6,150,330.50 awarded for pain, suffering, disability impairment, and loss of enjoyment of life "was delineated down to cents on the dollar and reflected the [j]ury's opinion based on testimony and evidence throughout the trial. Therefore, this Court finds that the jury verdict is fair compensation."

Defendants contend that other plaintiffs have recovered less "in similar cases." However, the cases cited in defendants' brief involved settlements, not jury verdicts. The Chirallo matter, which resulted in a $1,350,000 settlement, did not involve an amputated leg but rather broken bones and one year of painful medical treatment to avoid amputation. The Helman settlement involved public entity immunity issues that were denied in motions just prior to the settlement and involved an amputee in his fifties, who settled at $1,200,000. The Reyes-Montenes settlement for $1,425,000 does not indicate the plaintiffs age, and was complicated by issues of whether the general contractor or the employer-subcontractor had liability for the worker's on-the-job injury. The Tomquist settlement is most comparable to the present matter, involving a thirty-year-old amputee who settled at $5,550,000. Our Court has cautioned that "a pre-trial settlement offer is entirely irrelevant in a remittitur case in which the fundamental inquiry is not what anyone thought the case was worth beforehand, but whether the jury could have reached the verdict on the evidence actually before it." Jastmm, supra, 197 N.J. at 233, 962 A.2d 503.

Here, the "verdict may only be set aside if it is wide of the mark and pervaded by a sense of wrongness," and the verdict "is [not] so disproportionate to the injury and resulting disability as to shock the conscience and [convince the court] that to sustain the award would be manifestly unjust." Ming Yu He, supra, 207 N.J. at 249 (internal quotation marks omitted). Against these standards, we see no error.

B.

Finally, we agree with plaintiff that we should preserve the damage award even if we conclude that a new trial on liability is warranted.9 The disputed predicate facts regarding the discretionary or ministerial nature of defendants' actions are separate and distinct from plaintiffs claim for damages.

The "general rule [is] that issues in negligence cases should be retried together unless the issue unaffected by error is entirely distinct and separable from the other issues." Ahn v. Kim, 145 N.J. 423, 434, 678 A.2d 1073 (1996); accord Ogbome v. Mercer Cemetery Corp., 197 N.J. 448, 461, 963 A.2d 828 (2009) (holding that issues of proximate causation and comparative negligence were "intertwined" with issue of duty, thereby requiring retrial on all three issues); Conklin v. Hannoch Weisman, 145 N.J. 395, 410, 678 A.2d 1060 (1996) (ordering retrial of both proximate causation and negligence because the issues were not "distinct and separable"); Martin v. Prime Hospitality Corp., 345 N.J.Super. 278, 293, 785 A.2d 16 (App.Div. 2001) (stating that the failure to apportion liability did not affect the damage award); Truchan v. Sayreville Bar & Rest, Inc., 323 N.J.Super. 40, 53, 731 A.2d 1218 (App. Div.1999) (indicating that "the damages issue need not be relitigated [because] we conclude that the liability issues and the damages issues were fairly separable").

This is not a situation where the judge issued a flawed final jury charge on proximate causation, thereby prompting a request that a re-trial on all issues occur. and then found that the proximate causation and negligence issues were not "distinct and separable." Nor is this a matter where the jury considered the severity of defendants' conduct in the context of a claim for punitive damages. In fact, no claim for punitive damages is permitted against public entities. N.J.S.A. 59:9-2(c). Rather, the error in the charge warranting a new liability trial pertains to the discretionary or ministerial nature of defendants' conduct. A re-trial on liability, then, would relate to whether defendants had the discretion to determine, in the face of competing demands, whether and how to apply their existing resources. The issues in such a trial are separate and distinct from issues pertaining to compensation for pain and suffering, economic loss, and for future medical treatment.

V.

Two additional arguments by defendants warrant only brief mention here. First, defendants contend that the trial court erred in permitting plaintiff to submit surprise rebuttal evidence regarding mutual aid. Although we need not reach this issue because we are reversing the liability judgment, we do so for completeness. McKaig testified on direct examination that defendants never called local police departments as first responders. Plaintiff produced Frederick J. Wood as her rebuttal witness, who testified that the Pleasantville Police Department provided mutual aid to the NJSP. Defendants then produced Jeffrey Anderson, who testified about the lack of written standards regarding mutual aid. Defendant therefore opened the door to the rebuttal evidence and was not prejudiced by it.

Second, defendants argued for the first time that the verdict of no cause of action as to Raddi was against the weight of the evidence. Ordinarily, we will decline to consider questions or issues not properly presented to the trial court when an opportunity for such a presentation is available, "`unless the questions so raised on appeal go to the jurisdiction of the trial court or concern matters of great public interest.'" Nieder v. Royal Indem. Ins. Co., 62 N.J. 229, 234, 300 A.2d 142 (1973) (quoting Reynolds Offset Co., Inc. v. Summer, 58 N.J.Super. 542, 548, 156 A.2d 737 (App.Div.1959), cert. denied, 31 N.J. 554, 158 A.2d 453 (1960)). Neither exception applies here, but because we may dispose of the arguments summarily, and in the interest of justice, we address defendants' contention. There is ample evidence that Raddi non-negligently skidded on black ice. See Universal Underwriters Grp. v. Heibel, 386 N.J.Super. 307, 322, 901 A.2d 398 (App.Div. 2006) (stating that skidding "is not in itself sufficient to justify an inference of negligence").

VI.

On her cross-appeal, plaintiff contends that the judge erred by failing to award her pre-judgment interest pursuant to Rule 4:58-2(a)(2). She argues that the judge violated the separation of powers doctrine by erroneously concluding that the Act prohibited such interest.

The offer of judgment rule allows a party to take a judgment against it for a sum certain. R. 4:58-3. "The fundamental purpose of the rule is to induce settlement by discouraging the rejection of reasonable offers of compromise." Best v. C & M Door Controls, Inc., 200 N.J. 348, 356, 981 A.2d 1267 (2009). The consequences of rejecting an offer of judgment are expressed in Rule 4:58-2, which states in pertinent part that

Where a settlement offer is more favorable to the losing party than the ultimate judgment, the goal of the rule is achieved by imposing fees and costs. Ibid.

N.J.S.A. 59:9-2(a), on the other hand, states that "[n]o interest shall accrue prior to the entry of judgment against a public entity or public employee." Thus, there is tension between the rule and statute.

The drafters of the New Jersey Constitution of 1947 expressly stated that

"That bedrock principle is one of independence and interdependence among the coordinate branches of our government." In re Advisory Comm. on Prof I Ethics Opinion 705, 192 N.J. 46, 54, 926 A.2d 839 (2007). The doctrine "`contemplates that each branch of government will exercise its own powers without transgressing upon the powers rightfully belonging to a cognate branch.'" Id. at 55, 926 A.2d 839 (quoting Knight v. Margate, 86 N.J. 374, 388, 431 A.2d 833 (1981)).

Nevertheless, "our Constitution encourages cooperation among the branches." Ibid. For example, the Court has shared jurisdiction with the Legislature regarding the Court's express authority to "have jurisdiction over the admission to the practice of law and discipline of persons admitted," ibid, (citing N.J Const, art. VI, § 2, ¶ (3), and "uplield narrowly-circumscribed legislation that touches on attorney discipline," ibid, (citing McKeown-Brand v. Trump Castle Hotel & Casino, 132 N.J. 546, 554, 556, 626 A.2d 425 (1993)).

Another example of cooperation among the branches is found in Busik v. Levine, 63 N.J. 351, 373 n. 10, 307 A.2d 571, appeal dismissed sub nom. Levine v. Busick, 414 U.S. 1106, 94 S.Ct. 831, 38 L.Ed.2d 733 (1973) (involving the validity of Rule 4:42-ll(b), which authoriz[es] prejudgment interest in tort actions), where the Court explained the rule's interaction with the Act:

Likewise, in Potente v. County of Hudson, 187 N.J. 103, 114, 900 A.2d 787 (2006) (internal quotation marks omitted), the Court rejected as "simply wrong" the analysis of some prior cases that "prejudgment interest will not be awarded against a public entity except where provided by statute." The Court explained that

We agree with defendants' contention in their brief that permitting pre-judgment interest against a public entity pursuant to the offer of judgment rule would "render meaningless the [Court's] amendment of [Rule] 4:42-11[, which excludes] public entities in deference to the [Act, because] all a litigant would have to do to bypass [the bar against pre-judgment interest] would be to make an offer of judgment." Here, we do our best to harmonize our constitutional powers with the will of the Legislature. In re Advisory Comm. on Prof'l Ethics Opinion 705, supra, 192 N.J. at 56, 926 A.2d 839.

We have carefully considered the remaining contentions that the parties have raised and have determined that those arguments lack sufficient merit to address in this written opinion. R. 2:11-3(e)(1)(E).

We reverse the judgment on liability, remand for a new trial, and affirm in all other aspects.