Generally, the airlines like Southwest, Delta, and some of TBIT use the north runways for departure. American, Alaska, JetBlue, Spirit, United etc use the South runways. Tbit seems to be split down the middle but generally airlines use the closest runway TBIT is not quite as important. I fly mostly Southwest flights, and for some reason they refuse to taxi to 24L they go all the way around TBIT and go to 25R to take off.