Chicago Department of Transportation (CDOT), Division of Infrastructure Management (DIM), operates Chicago’s “One Call” service—known as “811 Chicago.” Per Municipal Code of Chicago (MCC) § 10-21-080, “in the event of damage to any underground facilities, the person responsible for the damage shall immediately notify…811 Chicago.”

811 Chicago records all reported damages as “hit tickets.” This dataset contains hit tickets since January 1, 2020. (Prior to that date, hit tickets data is a less reliable measure of utility damages.)

Please note, a hit ticket does not necessarily mean damage occurred or implicate the parties listed on the hit ticket as having caused the damage. For example, an excavator may report damage they discovered, but did not cause; an entity may incorrectly report the utility that was damaged or who caused the damage; the same damage may be reported by more than one entity. 811 Chicago investigates all reported damages to determine if there was a violation of MCC § 10-21. During the course of its investigation, 811 Chicago will confirm the information on the hit ticket. If 811 Chicago discovers inaccurate information, it may not update the hit ticket. The data related to 811 Chicago’s investigation is not exposed in this data set. Importantly, 811 Chicago does not determine which entity is liable for the damage, and the “hit by” field does not indicate that the individual or entity caused the damage or violated MCC § 10-21.