I8 or I-8 may refer to: Interstate 8, a highway in the southwestern United States Interstate 8 (EP), an extended play by Modest Mouse Resistance: Fall of Man, a video game originally known as I-8 Straight-eight engine, an uncommon internal combustion engine , a submarine of the Imperial Japanese Navy BMW i8, a plug-in hybrid sports car Uppland Regiment, a Swedish Army infantry regiment disbanded in 1957 i8, a name for the 8-bit signed integer, especially in Rust