[Abagail]

If you want to only delete unoccupied ones you could do:

pawn Код:

CMD:destroyncars(playerid, params[])
{
    #pragma unused params
    new count = 0;
    for(new i = 0; i < MAX_VEHICLES; i++)
    {
        if(IsVehicleOccupied(i)) return 0;
        if(NormalCar[i] == 1) DestroyVehicle(i);
        Count++;
    }
    if(!count) return SendClientMessage(playerid, COLOR_RED, "There Are No Vehicles To Delete.");
    return 1;
}

stock IsVehicleOccupied(vehicleid)
{
foreach(Player, i) {
if(GetPlayerVehicleID == vehicleid) return 1;
else return 0;
}
}

Untested.