It doesn't even take up much room, even if you travel with considerable water supplies (which takes up the most room and also is the most important, both for obvious reasons).

Almost everything else on the list is space efficient and/or packs in specific areas in your car made to store things like tools, spare tires, etc. People have a lot of room in their vehicles that go to waste simply because they don't read user manuals.

I would include a folding saw, I believe Silky to be the best and most reliable. Much better than a a small ax.