[aRoach]

Well count how many cars do you have in your GameMode and do THIS :

pawn Код:

CMD:despawnallveh( playerid )
{
    if(IsPlayerAdmin(playerid))
    {
        for(new i = 0; i < NUMBER_OF_VEHICLES; i++)
        {
            new string[64], pName[MAX_PLAYER_NAME];
            GetPlayerName(playerid, pName, MAX_PLAYER_NAME);
            format(string, sizeof string, "~b~Admin: ~g~%s ~r~has despawned all vehicles", pName);
            GameTextForAll(string, 5000, 5);
            SetVehicleToRespawn(i);
        }
    }
    else SendClientMessage(playerid, COLOR_RED,"You do not have access to this command");

    return 1;
}

You can add a define: #define NUMBER_OF_VEHICLES (Your number of Vehicles)