OPINION
MEYER, Justice.
This case presents the issue of whether St. Louis County and its road grader operator are immune from liability in a claim for the wrongful death of Joshua Schroeder. Schroeder, the son of appellants Michael and Kimarie Schroeder, was killed when the car he was driving collided head-on with a road grader driven by Stephen Ario, a St. Louis County grader operator. The Schroeders filed a wrongful death action against the county and Ario. The district court granted summary judgment to Ario and the county on the basis of statutory immunity, official immunity, and vicarious official immunity. The court of appeals upheld the grant of summary judgment. We affirm on the basis of statutory immunity, but reverse, in part, the grant of summary judgment on official immunity and vicarious official immunity.
Ario started work on November 9, 2000, at 8 a.m. Ario’s supervisor instructed him to grade all of his assigned roads that day, even if it required working overtime. One of the roads on Ario’s work list was a two-mile stretch of County State-Aid Highway 29 (CSAH 29). CSAH 29 was under construction at the time and the road surface consisted of milled asphalt and gravel. Although Ario usually ended his day around 3 p.m., he knew from experience that CSAH 29 would be warmer and easier to grade later in the afternoon, so he planned to begin to grade CSAH 29 around 3 p.m.
According to Ario, St. Louis County grader operators employ two methods for grading gravel roads. The first method is to “cut both sides of the roadway to the center and then use a squared moldboard blade * * * to feather the windrow from the center back across the roadway.” This method requires three passes: two passes to move the road material to the center of the road, and one pass to “feather” or spread the material back over the road. The second method is to cut material from one side of the roadway and move it all the way across the roadway. This method requires a second pass to move the material back across the roadway and often results in effective grading with only two passes.
[501]*501When Ario arrived at the southern end of the two-mile stretch of CSAH 29, he considered the two methods of grading and decided to use the second grading method because of the nature of the road material and the condition of the road. He made his first pass with the grader while traveling northbound in the east traffic lane. He made a second pass while traveling southbound in the west traffic lane. As he was making the southbound pass he determined that two additional passes would be necessary to effectively grade the road.
He then made a third pass beginning in the west lane of traffic rather than the east lane. He asserts that the third pass had to be in the west lane because he had already cut and moved material from the east side of the roadway to the west side. If he again started in the east lane, it would result in an uneven road with the west side being higher than the east side. However, rather than driving the grader to the north end of the roadway to begin grading the west lane (deadheading), he decided to grade the west lane by grading against traffic. In other words, he graded the wrong way in the west traffic lane.
Ario testified at his deposition that grading against the direction of traffic was an acceptable practice in St. Louis County. If the road graders did not grade against traffic, they would need to deadhead. Deadheading means that rather than grade against traffic, the grader operator would pick up the blade and run back to the other end of the road to start the next pass. Ario testified that he was never instructed to grade against traffic, but he was aware that grader operators were permitted to do so to avoid having to deadhead.
After completing the northbound pass, Ario proceeded to grade the east. lane, again grading against traffic, traveling southbound. He saw the Schroeder car with its headlights on heading toward him in the east lane of traffic. When Ario first saw the car, it was approximately one-half mile away. He became concerned when the car continued northbound in the east lane without slowing down. He began considering his options to avoid a collision and ultimately .concluded that the safest thing to do was to stop the grader in the east lane of traffic and allow the car to go around it. Ario expected the car to move out of the lane to avoid hitting his grader. Instead, the car collided head-on with Ario’s grader and Schroeder was killed.
The parties dispute the exact time of the accident and whether the grader’s lights were operating. Sunset was at 4:44 p.m. Law enforcement received a call reporting the accident at 5:07 p.m. The Schroeders assert that the accident happened as late as 5:15 p.m. Ario testified that he turned on his headlights and work lights approximately 20 minutes prior to the accident because the sun was beginning to set. Ario further testified that CSAH 29 was mostly tree-lined and it was cloudy while he was grading the road. Ario also stated that the grader’s strobe light had been on since he left the garage at the beginning of his workday.
The Schroeders submitted evidence that Ario’s headlights were not on just prior to the accident. Aaron Vandeveer was driving southbound on CSAH 29 in the west lane of traffic at approximately 5 p.m. According to Vandeveer’s affidavit, he passed Ario’s grader while it traveled southbound in the east lane of traffic. According to Vandeveer, he could not see any operating lights on the grader and had Vandeveer been traveling in the wrong lane of traffic, he would have collided with the grader because he could not see it. After Vande-veer proceeded past the grader, he continued further down CSAH 29 and passed [502]*502Schroeder’s car just minutes before it collided with Ario’s grader.
The county and Ario submitted evidence to the district court that the county had made a planning level decision to permit road grader operators to grade against traffic, thus entitling them to statutory immunity for that decision. The court reviewed a November 13, 1985, memorandum sent from Joe Varda, one of the county maintenance engineers, to the road and bridge maintenance employees. The memorandum provided in part:
Some of you have expressed concern about operation of equipment in which the vehicle crossed over the centerline; ie, snowplowing, ice control, and grading.
* * * *
This memo is sent to alleviate some of the fears you may have about operating your equipment.
Minnesota Traffic Regulations Statutes Chapter 169 contains the specific restrictions for use of the roadways. Subdivision 6 of Chapter 169.03, emergency vehicles, exempts motor vehicles and other equipment actually engaged in work upon the highway. If you are operating your equipment with routine care and the normally accepted safety precautions are taken (beacon, working lights, flags, etc.), you may operate on any part of the roadway. Naturally, if there are cases where sight distance is short either vertically or horizontally, either an attempt to improve the condition should be made or special precautions should be taken. Under normal conditions you should not worry about being ticketed for snowplowing, ice control, or blading across the centerline.
Before the memorandum was distributed to employees, including road grader operators, the head of the department and the county engineer reviewed and authorized its contents.
According to David Skelton, the county’s deputy public works director, the county has had a standing practice
for a number of years wherein we allow our grader operators to grade against traffic on gravel roads. * * * If [the road graders] did not grade against traffic, [they] would need to deadhead. ⅜ * * Deadheading means that rather than grade against traffic we would pick up the blade and run back to the other end of the road to start over when warranted.
On July 13, 1998, Assistant St. Louis County Attorney Michael Dean sent a letter to Richard Hansen, the St. Louis County highway engineer, expressing his concern over the grading process used in the county. Dean wrote:
We continue to receive reports of a substantial amount of grader activity occurring the wrong way of roadway center on our county roads. Do you have a written policy with respect to this issue? We are very concerned about these practices and particularly our concern [sic] with whether they are sanctioned by Public Works administration. * * * In my opinion, these practices are life threatening and in clear violation of Minnesota law. I am also enclosing a copy of Minn.Stat. § 169.18(5) for your review.
David Skelton discussed Dean’s concerns about grading during a meeting with the six district road superintendents. The superintendents participate in all aspects of operations including employment issues, budget, day-to-day project decisions, allocation of resources, and oversight of all activity within the district. The superintendents also provide input into all policy discussions, decisions, and directives. According to Skelton, they discussed the ex[503]*503isting practice of permitting grading against traffic, the cost of using pilot vehicles in front of and behind graders, and deadheading. Ultimately the superintendents came to the conclusion that deadheading would increase the time of grading by 20-83 percent.
Skelton then met with Hansen and they reviewed a videotape and a pamphlet from the Federal Highway Administration and the National Association of County Engineers. According to Skelton, the material suggested grading against the flow of traffic as a method of ensuring adequate distribution of aggregate on the roadway. As a result of Skelton’s meetings with the district road superintendents and his meeting with Hansen, Skelton and the superintendents determined that grading over the centerline or in the opposing lane would be unavoidable given the county’s budget, staffing and equipment, the increased amount of work that would need to be done, and the nature of the work that would be done.
Michael and Kimarie Schroeder, Joshua’s parents, filed a wrongful death suit against St. Louis County and Ario alleging: (1) Ario negligently operated his gravel road grader by grading the road heading southbound in the northbound lane of CSAH 29; and (2) St. Louis County is vicariously liable for Ario’s negligence. The district court granted summary judgment to Ario and the county on the basis of statutory immunity, official .immunity, and vicarious official immunity. The Schroeders appealed to the court of appeals. The court of appeals affirmed the district court in an unpublished decision. Schroeder v. St. Louis County, No. A04-97, 2004 WL 2283480 at *8 (Minn.App. Oct.12, 2004). • We affirm in part, reverse in part, and remand.
I.
In reviewing appeals from the grant or denial of statutory immunity on summary judgment, we must determine whether there are genuine issues of material fact and whether the district court erred in applying the law. Watson by Hanson v. Metro. Transit Comm’n, 553 N.W.2d 406, 411 (Minn.1996). When reviewing a summary judgment ruling, we consider the evidence in the light most favorable to the nonmoving party. Gradjelick v. Hance, 646 N.W.2d 225, 231 (Minn.2002).
The application of immunity presents a question of law that we review de novo. Gleason v. Metro. Council Transit. Operations, 582 N.W.2d 216, 219 (Minn. 1998). We have stated that municipalities are generally liable for the torts of their employees if the tort is committed within the scope of employment.1 Nusbaum v. County of Blue Earth, 422 N.W.2d 713, 718 (Minn.1988). But under statutory immunity, municipalities are immune from liability for “[a]ny claim based upon the performance or the failure to exercise or perform a discretionary function or duty, whether' or not the discretion is abused.” Minn.Stat. § 466.03, subd. 6 (2004). The purpose of statutory immunity is to protect the legislative and executive branches from judicial second-guessing of certain policy-making activities through the medium of tort actions. Nusbaum, 422 N.W.2d at 718. Thus, it is important for courts to focus on the idea that statutory immunity seeks to protect policy-based decisions and to prevent the impairment of effective government. Id. at 719.
[504]*504Government conduct is considered discretionary and thus protected by statutory immunity when the state produces evidence that the conduct was of a policy-making nature. Id. at 722 (citing United States v. Varig Airlines, 467 U.S. 797, 814, 104 S.Ct. 2755, 81 L.Ed.2d 660 (1984)); Steinke v. City of Andover, 525 N.W.2d 173, 175 (Minn.1994). To assist in determining whether the challenged conduct is protected, we distinguish between planning and operational functions. Nusb-aum, 422 N.W.2d at 722. Statutory immunity is extended when there has been a planning-level decision; that is, social, political, or economic considerations have been evaluated and weighed as part of the decision-making process. Holmquist v. State, 425 N.W.2d 230, 231-32 (Minn.1988). Statutory immunity does not extend to operational-level decisions, those involving day-to-day operations of government, the application of scientific and technical skills, or the exercise of professional judgment. Id. at 232.
To determine whether the county is entitled to statutory immunity, we must first identify the precise government conduct being challenged. Nusbaum, 422 N.W.2d at 722. In this case, the challenged government action is the county’s practice of permitting gravel road graders to operate against traffic.
The Schroeders contend that the county has not met its burden of demonstrating that it made a policy decision to grade roads against traffic. The county, on the other hand, asserts that such a policy was formulated and implemented, although the policy was unwritten. The district court determined that the county was entitled to statutory immunity because it had an unwritten policy that permitted grader operators to grade gravel roads against traffic. The court reasoned:
While there is admittedly no written policy, there is ample evidence of a longstanding practice that embodies a policy generated through a process whereby the County balanced various competing factors in deciding how county roads should be graded. It is clear that economic considerations and the making of choices from among various alternatives were involved in formulation of the grading practices reflected in the record.
The court of appeals also concluded that the county was entitled to statutory immunity. Schroeder v. St. Louis County, 2004 WL 2283480 at *4. The court of appeals reasoned:
The undisputed facts support the existence of an unwritten policy: (1) St. Louis County’s extensive history of grading over the centerline and against the flow of traffic; (2) Joe Varda’s 1985 memorandum addressing the permissibility of maintenance vehicles to cross the centerline while working on a road; (3) Varda’s 1985 memorandum was authorized by the department head and county engineer prior to distribution; (4) in 1998, at the request of Dean, Skelton and Hansen conducted a thorough review of the unwritten policy, including reviewing material from the Federal Highway Administration and National Association of County Engineers regarding the blading of roads; and (5) Skelton and the six road superintendents ultimately determined that grading over the centerline was unavoidable given the county’s budget, staffing, equipment, as well as the nature and amount of work to be performed.
Id. at *4. The court held that statutory immunity applied because the county balanced safety and economic considerations in reaching the determination that it should retain its current practice of grading against traffic. Id.
[505]*505First, we must determine if the county demonstrated that it permitted grader operators to grade against traffic as a result of engaging in the balancing of social, economic, or political considerations. The record establishes that a core function of the maintenance division of the St. Louis County Public Works Department is the maintenance of the county’s gravel road system. The county did not specify the precise date or circumstances that led to the practice of permitting grader operators to grade roads against traffic. The 1985 Yarda memorandum suggests that the practice had existed for a number of years before 1985. According to Skelton, the practice of grading against traffic was in place before 1998 "quite simply because St. Louis County could not afford to grade all its roads or could not perform some of our other key functions if the policy were not in place.” In any event, the continuation of the practice was revisited in 1998, when the county received a letter from Dean dated July 1998, expressing his concerns regarding the practice. The district road superintendents then met and, among other agenda items, discussed possible alternatives that would eliminate the need to grade against traffic while also accurately grading the county’s roads. During this meeting the economic impact of these alternatives was discussed as well as the social considerations. Hanson and Skelton also referenced a pamphlet and videotape that confirmed to them that grading against traffic was an acceptable practice.
The record supports the conclusion that the county had made a decision to permit grader operators to choose when to grade against traffic. Further, that decision was made on a planning level and was of a policy-making nature; therefore, wé affirm the district court and court of appeals and hold that the county is protected by statutory immunity for its decision to permit grader operators to grade against traffic.
II.
We next consider whether Ario is entitled to common law official immunity. Common law official immunity generally applies to prevent "a public official charged by law with duties which call for the exercise of his judgment or discretion” from being held personally liable to an individual for damages. Anderson v. Anoka Hennepin Indep. Sch. Dist. 11, 678 N.W.2d 651, 655 (Minn.2004) (quoting Elwood v. Rice County, 423 N.W.2d 671, 677 (Minn.1988)). Official immunity does not extend to officials “charged with the execution of ministerial, rather than discretionary, functions * * Anderson, 678 N.W.2d at 655. It must be kept in mind that “the mere existence of some degree of judgment or discretion will not necessarily confer common law official immunity; rather, the focus is on the nature of the act at issue.” Id. at 656. Official immunity does not apply: (1) when a ministerial duty is either not performed or is performed negligently, or (2) when a willful or malicious wrong is committed. Id. at 662.
The claim is that Ario negligently performed his ministerial duty by grading against traffic and. operating the grader without lights at dusk on a cloudy night. The district court found that Ario exercised professional judgment and discretion in determining what method he should use to grade the roads and whether he needed to use his headlights. The court concluded that because Ario’s operation of the grader was discretionary, his decision about his headlights was protected as a discretionary act. The court found that Ario’s actions were not willful or malicious because there was no “intentional violation of a known right required for a finding of malice.” To support its finding, the court cited Rico v. State, 472 N.W.2d 100, 107 (Minn. 1991) (stating that the willful or ma-[506]*506lieious wrong exception to official immunity applies only when the person seeking official immunity committed an act that he has reason to believe is prohibited). The court concluded, therefore, that Ario was entitled to official immunity.
The question before us then is whether Ario’s actions “called for the exercise of discretion * * * or instead were ministerial, constituting merely the execution of a specific duty arising from fixed and designated facts.” Anderson, 678 N.W.2d at 657. A duty is discretionary if it involves “more individual professional judgment that necessarily reflects the professional goal and factors of a situation.” Wiederholt v. City of Minneapolis, 581 N.W.2d 812, 315 (Minn.1998). However, a duty is ministerial if it is “absolute, certain, and imperative, involving merely the execution of a specific duty arising from fixed and designated facts,” Anderson, 678 N.W.2d at 659 (quoting Wiederholt, 581 N.W.2d at 315), that is, “the duty must dictate the scope of the employee’s conduct.” Anderson, 678 N.W.2d at 659.
In our recent Anderson decision, we dealt closely with the question of common law official immunity. 678 N.W.2d at 655-63. Anderson involved a suit by a parent against his child’s school district and wood-shop teacher seeking to recover damages for injuries the child suffered during a woodshop class. Id. at 654-55. The assertion in Anderson was that the teacher was not protected by official immunity because the decision to instruct the student on the use of the woodworking machinery was ministerial. Id. at 656. We agreed that the teacher’s instructional decision was ministerial in the sense that his teaching decision was controlled by department policy. Id. at 657. Nevertheless, we extended official immunity to the teacher because the department policy itself was being challenged and the decision adopting the protocol involved sufficient judgment and discretion to qualify for official immunity. Id. at 660.
In Anderson, it was the teacher’s compliance with the existing protocol that was the allegedly negligent conduct, and we treated it as a challenge to the protocol itself. Id. at 659-63. We held that official immunity is not forfeited because conduct is ministerial “if that ministerial conduct was required by a protocol established through the exercise of discretionary judgment that would itself be protected by official immunity.” Id. at 660. We explained further that the ministerial conduct bar to official immunity applies “when the allegation is that a ministerial duty was either not performed or was performed negligently.” Id. Because the challenge in Anderson was actually a challenge against the protocol, we assessed whether the adoption of the protocol “involved the exercise of the staffs professional judgment as educators and woodworkers.” Id. at 661. We held that the protocol was protected by official immunity and that the teacher was protected by official immunity as well. Id. at 662.
We consider first the claim that Ario negligently performed his ministerial duty by grading against traffic. Unlike the conduct in Anderson, the challenged conduct in this case does not arise from compliance with a protocol. Ario was acting according to an established policy of the county that permitted him to operate against traffic. The policy of the county gave him the discretion to decide, in the field, whether to operate against traffic. He was not required by an established protocol to grade against traffic. Because he was exercising individual professional judgment, Ario’s decision was discretionary in nature and is protected by official immunity.
[507]*507We turn to the Schroeders’ claim that Ario was negligent in operating the grader without lights at dusk on a cloudy night. The court of appeals concluded that there was no genuine issue of material fact related to the activation of the grader’s lights. Id. at *7. In support of this conclusion, the court quoted the district court’s memorandum of law:
It is true there is arguably some dispute as to whether or not Mr. Ario had his headlights on when the accident occurred. He says that he did. A witness who passed him before the accident says the headlights were not on when he passed the grader. He has nothing to say as to their state at the actual time of the accident, however. Both renditions could be correct factually. There is thus no factual dispute at all as of the actual time of impact and even the few minutes just before the accident. As the [c]ourt understands the state of the record, the witness relied upon by plaintiffs lacks foundation to testify one way or the other as to the state of the headlights just prior to and at the time of impact. The evidence appears undisputed that the strobe light was on.
See Schroeder, 2004 WL 2283480 at *1. We are concerned that the court of appeals may have set forth an incorrect legal standard when it wrote that summary judgment was appropriate in this case “because appellants have failed to establish by substantial evidence a genuine issue for trial.” Id. (emphasis added). A party need not show substantial evidence to withstand summary judgment. Instead, summary judgment is inappropriate if the nonmov-ing party has the burden of proof on an issue and presents sufficient evidence to permit reasonable persons to draw different conclusions. Gradjelick, 646 N.W.2d at 231. In this case the Schroeders are the nonmoving party and have presented an affidavit from Aaron Vandeveer, an independent witness, who asserts that just minutes before the collision he passed the road grader and that its operating lights were not on. Further, according to Vandeveer, had he been traveling in the same lane as the road grader his vehicle would have collided with the grader. On this record, the district court erred when it concluded that there was “no factual dispute at all [with respect to the grader’s lights] as of the actual time of impact and even the few minutes just before the accident.”
If we assume that Ario was operating the grader after sunset without operating lights, we must ask whether the failure to drive without lights was a ministerial or discretionary decision. We focus our inquiry on the nature of the act itself and acknowledge that in doing so almost any act involves some measure of freedom of choice. We find our decision in Williamson v. Cain, 310 Minn. 59, 245 N.W.2d 242 (1976), to be instructive. In Williamson, a state employee caused damage to an occupied house in the course of dismantling an abandoned house. Id. at 60, 245 N.W.2d at 243. The defendant state employees were using a caterpillar tractor when they intruded onto the adjoining house’s property causing damage. Id. at 60, 245 N.W.2d at 243. Further damage was caused to the house when the state employees attempted to pull a portion of the abandoned house down with the caterpillar tractor and a portion it fell against the house. Id. at 60, 245 N.W.2d at 243. Under these facts, we concluded in Williamson that the nature, quality, and complexity of the decision-making processes in tearing down the abandoned house were clearly ministerial because the job was “simple and definite.” Id. at 61, 245 N.W.2d at 244. In this case, as in Williamson, the nature, quality, and complexity of the road grader operator’s deci[508]*508sion related to the activation of vehicle lights is clearly ministerial.
In sum, Ario is entitled to common law official immunity on the claim that he was negligent in grading against traffic, but he is not entitled to immunity on the claim that he operated the grader at dusk without lights.
III.
The final issue presented in this case is whether the county is vicariously immune from suit on the claim that Ario was negligent in grading against traffic. In general, when a public official is found to be immune from suit on a particular issue, his government employer will enjoy vicarious official immunity from a suit arising from the employee’s conduct. Anderson, 678 N.W.2d at 663-64. Vicarious official immunity is usually applied “where officials’ performance would be hindered as a result of the officials second-guessing themselves when making decisions, in anticipation that their government employer would also sustain liability as a result of their actions.” Id. at 664. “This court applies vicarious official immunity when failure to grant it would focus ‘stifling attention’ on an official’s performance ‘to the serious detriment of that performance.’ ” Id. at 663 (quoting Olson v. Ramsey County, 509 N.W.2d 368, 372 (Minn. 1993)). Ultimately, the extension of vicarious official immunity is a policy question for the court. Anderson, 678 N.W.2d at 664.
Here, we conclude that the county is entitled to vicarious official immunity on the claim that Ario was negligent in grading against traffic. The decision to permit drivers to grade against traffic was based on the collective knowledge and experience of the county road superintendents and maintenance staff who took into consideration the various economic and safety factors discussed in Part I of this opinion. To fail to grant immunity to the county would create a disincentive in the county to use its experience and knowledge to create protocols and policies in the future with respect to the grading of its roads. We affirm the district court’s grant of summary judgment to the county on the claim that it was negligent to grade against traffic, for the reason that the county is protected by vicarious official immunity.
Affirmed in part, reversed in part, and remanded.
ANDERSON, G. BARRY, J„ took no part in the consideration or decision of this case.
GILDEA, J., not having been a member of this court at the time of the argument and submission, took no part in the consideration or decision of this case.