DANHOF, C.J.
Plaintiff appeals as of right from an order of summary judgment granted in favor of defendant which dismissed plaintiff's claims.
Plaintiff's complaint alleges that he was injured as he was jogging along Washtenaw Avenue in Ypsilanti when he stepped on a stake which protruded approximately three to four inches out of the ground. He alleges that the stake was what remained of a traffic control sign which had been installed by defendant. He claims that defendant's agents were negligent in removing the sign without also removing the entire signpost.
The trial court ruled that plaintiff's claim was barred by governmental immunity. MCL 691.1407; MSA 3.996(107). The court rejected plaintiff's claim that the highway exception to governmental immunity applied:
"Sec. 2. Each governmental agency having jurisdiction over any highway shall maintain the highway in reasonable repair so that it is reasonably safe and convenient for public travel. Any person sustaining bodily injury or damage to his property by reason of failure of any governmental agency to keep any highway under its jurisdiction in reasonable repair, and in condition reasonably safe and fit for travel, may recover the damages suffered by him from such governmental agency. * * * The duty of the state and the county road commissions to repair and maintain highways, and the liability therefor, shall extend only to the improved portion of the highway designed for vehicular travel and shall not include sidewalks, crosswalks or any other installation outside of the improved portion of the highway designed for vehicular travel." MCL 691.1402; MSA 3.996(102).
Defendant claims that because the stake was located on a grass strip which was separated from the paved portion of the highway by a curb, the stake was an "installation outside of the improved portion of the highway designed for vehicular travel". We disagree.
The state's affirmative obligation to maintain highways in reasonable repair has consistently been held to include the duty to maintain traffic control signs once erected. O'Hare v Detroit, 362 Mich. 19; 106 N.W.2d 538 (1960); Austin v City of Romulus, 101 Mich. App. 662, 666; 300 N.W.2d 672 (1980); Williams v Dep't of State Highways, 44 Mich. App. 51; 205 N.W.2d 200 (1972); Lynes v St Joseph County Road Comm, 29 Mich. App. 51; 185 N.W.2d 111 (1970). The defendant in Lynes, supra, also claimed that a traffic sign located in a nonpaved area adjacent to the roadway was not part of the improved portion of the highway. In rejecting defendant's claim, the Court stated the following:
"Under defendant's interpretation of the statute, the duty of the defendant to keep the highways safe and fit for travel would be limited to the pavement itself and whatever equipment physically touches the pavement. Although this interpretation would provide a certain ease in the application of the statute, it would completely negate the first part of the statute, as well as that part of MCL 224.21; MSA 9.121, both of which impose the duty on the defendant to keep the highways safe and fit for travel. We cannot accept the argument that the legislature intended such a result. It is recognized law that in construing a statute effect must be given to every part of it and one part must not be so construed as to render another part nugatory. Sutton v Globe Knitting Works, 276 Mich. 200; 267 N.W. 815 (1936); Remus v City of Grand Rapids, 274 Mich. 577; 265 N.W. 755 (1936).
"Traffic signals which control the flow of traffic are an integral part of the improved portion of the highway. The presence or absence of such signals, as well as the conditions in which they are maintained, directly relates to the statutory duty imposed upon the defendant to maintain the highway in a condition safe and fit for travel." Lynes, supra, p 59.
In a recent decision of the Supreme Court, Salvati v Dep't of State Highways, 415 Mich. 708; 330 N.W.2d 64 (1982), six justices split evenly concerning the scope of the state's duty to erect and maintain signs to warn motorists of the hazards of preferential icing. However, all of the justices were in agreement that the statutory provision quoted earlier imposes a duty on the state to erect and maintain traffic signs. In an opinion written by Justice COLEMAN, she stated the following with respect to the duty of the state to maintain such signs.
"A traffic sign, once erected, becomes an integral part of the physical structure of the highway, and thus the duty to maintain a highway in reasonable repair encompasses the maintenance of traffic signs. A governing unit may incur liability under the broad concept of `traffic sign maintenance' in the following ways: for failing to properly maintain a sign placed on the roadway." Salvati, supra, p 715.
In our opinion, the foregoing makes it clear that, once the state erects a traffic sign, the sign becomes a part of the improved portion of the highway and that thereafter the statute imposes a duty upon the state to maintain such a sign in proper repair. Plaintiff's complaint properly states a claim in avoidance of immunity. The trial court erred by ruling to the contrary.
Plaintiff also claims that the trial court erred by dismissing his nuisance claim.
Only nuisances per se or intentionally created or continued nuisances in fact will defeat a claim of governmental immunity. Rosario v City of Lansing, 403 Mich. 124; 268 N.W.2d 230 (1978); Gerzeski v Dep't of State Highways, 403 Mich. 149; 268 N.W.2d 525 (1978).
A nuisance per se consists of an act, occupation or structure which is a nuisance at all times and under any circumstances, regardless of location or surrounding. Rosario, supra. In our opinion, plaintiff has not alleged a claim of nuisance per se. Not all stakes which protrude from the ground can be said to constitute a nuisance regardless of their location. On the contrary, in the present case, it was the location of the stake (next to a highway partially hidden by grass) which created the danger complained of. In other locations and under different circumstances such a condition would not present such a danger. Therefore, the trial court correctly granted summary judgment with respect to this claim.
To establish the necessary intent to support a claim of intentionally created nuisance in fact, plaintiff must show that the defendant who created or continued the nuisance knew or must have known that harm to plaintiff was substantially certain to follow. See Ford v Detroit, 91 Mich. App. 333, 336; 283 N.W.2d 739 (1979); Cobb v Fox, 113 Mich. App. 249, 257-258; 317 N.W.2d 583 (1982); Ovist v City of Hancock, 123 Mich. App. 276; 333 N.W.2d 250 (1983).
Plaintiff's complaint merely alleges in conclusionary terms that the nuisance constituted an intentionally created nuisance in fact. He failed to allege facts to support a claim that defendant intended to create or continue the condition or, more importantly, that defendant knew or must have known that the harm plaintiff suffered was substantially certain to follow. Therefore, plaintiff has failed to state a claim of nuisance in avoidance of immunity.
Reversed in part, affirmed in part, and remanded for trial on plaintiff's negligence claim. No costs.
ALLEN, J., concurred.