Plaintiff appeals as of right the Court of Claims’ order granting summary disposition to defendant. We affirm.

This case arises out of an incident where Jonathan Palmer, a minor, was struck by a car while crossing West Michigan Avenue at a designated crosswalk on the campus of defendant Western Michigan University. At each end of the crosswalk, defendant had erected a white, rectangular-shaped sign, directed toward vehicular traffic, with the word “stop” written in white letters on a red octagon and, beneath that, the words “for pedestrians” written in red letters. Plaintiff claims that defendant engaged in ultra vires conduct by erecting a nonconforming sign, that defendant breached its duty to maintain the highway in reasonable repair so that the highway was safe for public travel, and that the erection of the sign constituted a nuisance per se.

Plaintiff first argues that the Court of Claims erred in rejecting his claim that defendant was not entitled to the benefit of governmental immunity because its action of designing and erecting a “stop for pedestrians” sign was ultra vires. We disagree. When a governmental agency engages in an activity that is expressly or impliedly mandated or authorized by constitution, statute, or other law, it is performing a governmental function and is immune from tort liability. Ross v Consumers Power Co (On Rehearing), 420 Mich 567, 620; 363 NW2d 641 (1984). In this case, we *142 conclude that defendant was impliedly authorized, pursuant to MCL 390.891; MSA 15.1120(51), to erect a “stop for pedestrians” sign that regulated traffic on its campus.

MCL 390.891; MSA 15.1120(51) expressly authorizes a state university, such as defendant, to regulate vehicular and pedestrian traffic on its campus. Erection of a traffic sign to protect pedestrians is an extension of that authority. Thus, defendant’s conduct was not ultra vires because it was impliedly authorized to erect the “stop for pedestrians” sign. Furthermore, even though defendant may have performed the activity improperly by designing and erecting a sign that did not conform to the specifications outlined in the Michigan Manual of Uniform Traffic Control Devices, the activity is still considered a governmental function and defendant is still protected by governmental immunity. Richardson v Jackson Co, 432 Mich 377, 385-386; 443 NW2d 105 (1989).

Plaintiff next argues that the Court of Claims erred in finding that plaintiff’s claim against defendant did not fall under the highway exception to governmental immunity provided by statute, MCL 691.1402(1); MSA 3.996(102)(1). Again, we disagree. Section 2(1) provides, in pertinent part:

Each governmental agency having jurisdiction over a highway shall maintain the highway in reasonable repair so that it is reasonably safe and convenient for public travel. A person sustaining bodily injury or damage to his or her property by reason of failure of a governmental agency to keep a highway under its jurisdiction in reasonable repair, and in condition reasonably safe and fit for travel, may recover the damages suffered by him or her from the governmental agency. . . . The duty of the state and the county road commissions to repair and maintain highways, and the *143 liability for that duty, extends only to the improved portion of the highway designed for vehicular travel and does not include sidewalks, crosswalks, or any other installation outside of the improved portion of the highway designed for vehicular travel.

Section 2(1) explicitly states that the duty of the state to maintain and be liable for highways does not include crosswalks. This limiting sentence of the highway exception applies to defendant. 1

This language was recently interpreted by our Supreme Court in Mason v Wayne Co Bd of Comm’rs, 447 Mich 130; 523 NW2d 791 (1994), amended 451 Mich 1236; 549 NW2d 575 (1996). There, the plaintiff, while crossing a street, was struck by a car that ran a red light at the intersection. He sued Wayne County, alleging that Wayne County failed to maintain the streets and intersection in reasonable repair by not installing stop signs, a pedestrian overhead walkway, a flashing red stoplight, school advance signs, school crossing signs, school speed limit signs, and school pavement markings. 447 Mich 133. Our Supreme Court rejected this claim, interpreting § 2(1) as excluding from the highway exception “specific installations whose only rational purposes narrowly service the unique needs of pedestrians.” Id. at 136. Similarly, plaintiffs claim here must fail. Because the only rational purpose of the “stop for pedestrians” sign narrowly services the unique needs of pedestrians, defendant’s actions of designing and erecting the *144 sign do not fall within the highway exception to the governmental immunity act. 2

Plaintiff also argues that the Court of Claims erred in finding that defendant’s design and erection of the “stop for pedestrians” sign was not a nuisance per se. We disagree. A nuisance per se is “an activity or condition which constitutes a nuisance at all times and under all circumstances, without regard to the care with which it is conducted or maintained.” Li v Feldt (After Second Remand), 439 Mich 457, 476-477; 487 NW2d 127 (1992). In Li, id. at 462-463, the plaintiff argued that an improperly timed traffic light, which was operated by the City of Ann Arbor, caused an automobile accident. Our Supreme Court rejected the plaintiff’s claim and held that the operation of a traffic light cannot be considered “an intrinsically unreasonable or dangerous activity, without regard for care or circumstances.” Id. at 477. The Court stated that the operation of a traffic light serves a beneficial public purpose and is quite capable of being performed in a manner so as not to pose any nuisance. Id.

In this case, we conclude that the “stop for pedestrians” sign cannot be considered a nuisance per se. Rather, the sign, like the improperly timed traffic light in Li, serves a beneficial public purpose by warning motorists that they must stop for crossing pedestri *145 ans. The crosswalk area becomes dangerous only when an inattentive driver, like the driver in the present case, overlooks the sign or notices it but chooses to ignore it. Although the sign in this case might have been designed better, like the light in Li might have been timed better, its placement at the crosswalk does not “constitute an intrinsically unreasonable or dangerous activity, without regard for care or circumstances,” id., and it is not a nuisance per se.

We affirm.