As mentioned in
viewtopic.php?f=6&t=1190Quote:
usability
...
* objective markers
It goes without saying that the game needs to seriously step up the usability area and offer better direction on what to do and where to go (but not too much, mind you), and we're slowly but surely getting there. So far we haven't paid much at all attention to this area as we've got our hands full on other (less boring) stuff

Now that we've finally reached 0.90, we can start to look into usability too.
Anyway, currently you can deliver the cargo truck to armories, or the hangars and camo tents that actually look like something you should drive a vehicle into, armories are marked on the map. 0.89 has several serious bugs related to cargo truck delivery objective, so chances are it didn't even work most of the time.