FYI, this is in relation to an "arrestee", but the takeaway is that "immediate control" refers to the area "within an individual's reach" : "In criminal law, immediate control refers to an area within an arrestee’s reach. A police officer may conduct a warrant less search of the area to ensure the safety of the officer and also to prevent the arrestee from destroying evidence. The term also includes the arrestee’s person and the area from within which s/he might gain possession of a weapon or destructible evidence. [United States v. Beltran-Palafox, 2010 U.S. Dist. LEXIS 54541 (D. Kan. June 3, 2010)]."