I-76 is Interstate 76 in Pennsylvania, also known as the Schuylkill [pronounced "school kill"] Expressway. It's a love letter to G. Love's hometown of Philadelphia, recounting the good times he had growing up in the city. The NBA team, the 76ers, gets lots of attention here, with a number of players from their early '80s teams mentioned, notably Julius Erving and Moses Malone. That team won the championship in 1983.
Two other Philly rappers joined forces with G. Love on this track: Katman and Smiles. All three are credited as writers on this track, collectively called the All Fellas Band.