What are standard procedures designed to simplify clearance delivery and expedite departing traffic called?

The correct answer is SID, which stands for Standard Instrument Departure. SIDs are specifically designed routes that aircraft follow after takeoff, enabling efficient airflow and streamlined communication with air traffic control. These standardized procedures help reduce congestion and improve the overall efficiency of departure traffic by providing predefined paths for aircraft to follow. This simplifies clearance delivery, as air traffic controllers can provide pilots with concise instructions that incorporate these set routes.

SIDs contrast with other options. For instance, STARs (Standard Terminal Arrival Routes) are used for arrivals rather than departures, while SOPs (Standard Operating Procedures) refer to general operational guidelines rather than specific departure routes. The term "ATC Procedures" is broader and lacks the specificity of SIDs when discussing procedures meant to facilitate departing traffic.