PRESIDING JUSTICE BOWMAN delivered the opinion of the court:

Plaintiff, D.M., attended school at a public facility operated by defendant Special Education District of Lake County (SEDOL). SEDOL assigned its students to be transported to and from school by various buses, each of which traveled a different route. The buses were operated by defendant National School Bus Service, Inc. (NSBS), which is not a party to this appeal.

Plaintiff sued defendants to recover damages for injuries that were allegedly inflicted upon him by another student while he was riding his bus home from school. Count II of plaintiff's amended complaint alleged that SEDOL willfully and wantonly assigned him to ride a bus with his assailant, who was known to have previously abused him, and that SEDOL willfully and wantonly failed to protect plaintiff from that known danger. As a result, plaintiff alleged, plaintiff suffered serious physical harm. SEDOL moved to dismiss count II pursuant to section 2--619(a)(9) of the Code of Civil Procedure (735 ILCS 5/2--619(a)(9) (West 1996)). SEDOL claimed, inter alia, that it was entitled to immunity under section 2--201 of the Local Governmental and Governmental Employees Tort Immunity Act (Tort Immunity Act) (745 ILCS 10/2--201 (West 1996)). The trial court granted SEDOL's motion and dismissed count II with prejudice.

Pursuant to Supreme Court Rule 304(a) (155 Ill. 2d R. 304(a)), the court entered an order finding no just reason to delay the enforcement or appeal of its order dismissing count II. Plaintiff now appeals to this court, arguing that neither section 2--201 of the Tort Immunity Act nor any other applicable law makes SEDOL immune to plaintiff's complaint. We affirm.

A dismissal based on section 2--619 of the Code of Civil Procedure must be reviewed de novo. Epstein v. Chicago Board of Education, 178 Ill. 2d 370, 383 (1997). Plaintiff first argues that the trial court misapplied section 2--201 of the Tort Immunity Act to afford immunity to SEDOL.

Section 2--201 states as follows:

"Except as otherwise provided by Statute, a public employee serving in a position involving the determination of policy or the exercise of discretion is not liable for an injury resulting from his act or omission in determining policy when acting in the exercise of such discretion even though abused." 745 ILCS 10/2--201 (West 1996).

Plaintiff initially suggests that this section does not immunize a public employee who causes injury through willful and wanton conduct, such as that alleged by plaintiff. Despite earlier holdings that agreed with that assertion, the supreme court recently ruled that only the explicit language of the statute can limit the immunity provided. In re Chicago Flood Litigation, 176 Ill. 2d 179, 196 (1997). Because section 2--201 does not explicitly exclude willful and wanton conduct from its coverage, it encompasses the acts alleged here.

Plaintiff correctly states that the section affords immunity to a public employee only if his alleged wrongful act or omission was both a determination of policy and an exercise of discretion. Harinek v. 161 North Clark Street Ltd. Partnership, 181 Ill. 2d 335, 341 (1998). Plaintiff apparently concedes that SEDOL is staffed by public employees, but he argues that SEDOL's act of assigning him, without protection, to a bus with a student who posed a known risk to him was not both a policy determination and a discretionary act. Therefore, plaintiff concludes, section 2--201 provides no immunity to SEDOL.

The Tort Immunity Act does not offer statutory definitions of the concepts of "policy" and "discretion," and courts have therefore continued to employ common-law definitions. See Snyder v. Curran Township, 167 Ill. 2d 466, 473 (1995). A determination of policy is one that requires the balancing of competing interests and the making of a judgment as to what solution will best serve each. West v. Kirkham, 147 Ill. 2d 1, 11 (1992).

In Harinek, for example, the plaintiff alleged that, during a fire drill, a city fire marshal negligently directed her to stand near a heavy door without warning her of the possibility of injury. As a result, the plaintiff alleged, she was hit and injured by the door during the drill. Harinek, 181 Ill. 2d at 338. The supreme court ruled that the fire marshal's decisions about where individuals should be placed and what warnings should be given were made through a balancing of "various interests which may compete for the time and resources of the [fire] department, including the interests of efficiency and safety." Harinek, 181 Ill. 2d at 342. Therefore, the court concluded, the public employee made a determination of policy within the meaning of section 2--201. Harinek, 181 Ill. 2d at 343.

We conclude that SEDOL's alleged wrongful act was a similar determination. Contrary to plaintiff's suggestion, we do not perceive the process by which a school decides which students to assign to each bus to be a simple one. The school must presumably consider a variety of factors, such as the number of available buses and drivers, the distance each bus would travel, the number of students who live in each surrounding neighborhood, the capacity of each bus, local traffic patterns, and so on. See Posteher v. Pana Community Unit School District No. 8, Christian County, 96 Ill. App. 3d 709, 713 (1981). The school must then reach a decision that fulfills a set of seemingly incompatible objectives, including speed, safety, and cost-effectiveness. This is a complex calculus that clearly requires the balancing of competing interests and the making of a judgment that will satisfy them most efficiently. Therefore, SEDOL's decision to assign plaintiff as it did was a determination of policy.

Plaintiff also contends that SEDOL's act was not an exercise of discretion but rather a merely ministerial act that deprived it of immunity under section 2--201. See Harinek, 181 Ill. 2d at 341.

"[D]iscretionary acts are those which are unique to a particular public office, while ministerial acts are those which a person performs on a given state of facts in a prescribed manner, in obedience to the mandate of legal authority, and without reference to the official's discretion as to the propriety of the act." Snyder, 167 Ill. 2d at 474.

Defined another way, the making of a decision about whether or how to perform an act is generally discretionary, whereas the actual mechanical performance of the act is merely ministerial. See Herman v. Will Township, 284 Ill. App. 3d 53, 59 (1996).

Plaintiff correctly states that SEDOL is statutorily obligated to provide transportation to all of its students who live more than 1