Only used once in the decompiled scripts. Seems to be related to scripted vehicle generators.
Modified example from "am_imp_exp.c4", line 6406:
/* popSchedules[0] = ZONE::GET_ZONE_POPSCHEDULE(ZONE::GET_ZONE_AT_COORDS(891.3, 807.9, 188.1));
etc.
*/
ZONE::OVERRIDE_POPSCHEDULE_VEHICLE_MODEL(popSchedules[index], vehicleHash);
STREAMING::REQUEST_MODEL(vehicleHash);