Constructive notice, by contrast, does not require proof that the public entity actually knew about the specific dangerous condition. Instead, Government Code section 835.2 allows a plaintiff to establish notice by showing that the condition existed for a sufficient period of time, and was of such an obvious nature, that the public entity should have discovered it through the exercise of reasonable care, and that the entity had a reasonable opportunity to correct it before the injury occurred. Constructive notice claims often turn on evidence about the public entity's inspection practices, or lack thereof. If a public entity has no regular inspection protocol for a particular type of infrastructure, or if its inspection protocol was not followed with respect to the specific location at issue, this can support an argument that a reasonably diligent inspection program would have discovered the dangerous condition well before the injury occurred. Expert testimony from civil engineers or municipal safety consultants about industry-standard inspection intervals and practices is frequently used to establish what a reasonably diligent public entity should have discovered and when.