[KaleOtter]

new VehicleGod[MAX_PLAYERS]; // on top of gamemode

if(strcmp(cmdtext, "/test", true)==0) // in onplayercommand
{
if(VehicleGod[playerid] == 0)
{
VehicleGod[playerid] = 1;
// Here you fuction set vehicle god on

}
else
{
VehicleGod[playerid] = 0;
// Here you fuction (set vehicle god off)

}

}