I just learning English from magazine. Today I learned a word about "zoom" , that means moving so fast. There's an example with this word.
The car zoomed down the highway.
For this, I don't know why does writer using "down" in this sentence. and is "down" acting preposition in the sentence?
Prepositions can be squirmy things, and not just in English. They don't always mean what you expect, or even the same thing between different verbs. For example, you can be locked up and locked down at the same time. You can take something down but the opposite of that is not taking something up.
In your particular case, you can zoom (or move, or walk, or travel) down a highway, but you can do the same thing up the highway and it doesn't necessarily mean something different. In point of fact, movement up or down a highway may suggest a difference, but one that may be idiosyncratic to the speaker's perspective, something like the difference between downtown and uptown. It might be related to geography, but just as easily it might not.
You really have to take prepositions as they come and simply try to understand them in context. Don't try to relate them to the prepositions in your own native tongue (if you even have prepositions), because they won't match even when you think they ought to.
Yes, down is a preposition we use with roads, paths, etc. You can also use up and along. Britain is very hilly, so often we actually are going up or down a hill. Along works best if it's a very flat road. You walk down, up, along a road when you go in the same direction as the road. If you walk to the other side of the road, then you walk across the road
In spoken English, we quite often use up or down without saying the road and only say the destination.
I'm just going down (the road) to the pub. I'm just going up to the shops
Here are two other prepositions you could use to mean travel + visit:
I'm going over to my brother's later.
Peter came around / round earlier.
