Which runway incursion category indicates little or no chance of collision?

Category D runway incursions represent situations where there is little or no chance of collision. This category includes incidents that do not indicate a conflict with an aircraft or vehicle on the runway, often involving an aircraft or vehicle departing from a taxiway or holding position without causing a safety hazard. The focus of Category D is on low-risk scenarios where safety is maintained, thereby keeping potential for collision at a minimum.

In contrast, the other categories denote increasing levels of risk. Category A indicates a serious incident where a collision is imminent and could potentially lead to extensive damage or injury. Category B involves situations where a collision is likely but has been avoided, often requiring immediate corrective action. Category C includes scenarios where an event has occurred that did not result in a collision, but involved close proximity between aircraft or vehicles which could have led to an incident. Thus, the clear distinction of Category D emphasizing minimal risk makes it the appropriate choice for indicating little or no chance of collision.