(a) Except as otherwise provided in this Article, a local public entity has the duty to exercise ordinary care to maintain its property in a reasonably safe condition for the use in the exercise of ordinary care of people whom the entity intended and permitted to use the property in a manner in which and at such times as it was reasonably foreseeable that it would be used, and shall not be liable for injury unless it is proven that it has actual or constructive notice of the existence of such a condition that is not reasonably safe in reasonably adequate time prior to an injury to have taken measures to remedy or protect against such condition.
     (b) A public entity does not have constructive notice of a condition of its property that is not reasonably safe within the meaning of Section 3-102(a) if it establishes either:
     (1) The existence of the condition and its character of not being reasonably safe would not have been discovered by an inspection system that was reasonably adequate considering the practicability and cost of inspection weighed against the likelihood and magnitude of the potential danger to which failure to inspect would give rise to inform the public entity whether the property was safe for the use or uses for which the public entity used or intended others to use the public property and for uses that the public entity actually knew others were making of the public property or adjacent property; or
     (2) The public entity maintained and operated such an inspection system with due care and did not discover the condition.