The nose, pharynx, larynx, trachea and bronchi all work like a system of pipes through which the air is funnelled down into our lungs. There, in very small air sacs called alveoli, oxygen is brought into the bloodstream and carbon dioxide is pushed from the blood out into the air.
And, just to clarify, the kitty litter in your trunk, to be used for traction, needs to be taken out and spread around your tires. Most cars are front wheel drive, so the extra weight alone in the back ain't gonna do you much good.
Another suggestion is to just use non-clumping cat litter. This may have two potential dangers: dust and especially for male hedgehogs, getting caught in the penile sheath -- the same as if you used it in a litter box [5.4], [9.1] (there can also be problems for females, though these are not as frequent).