a collision or the collision

I’d appreciate it if someone would answer my question about the following sentences. Thanks in advance.

A: Last year there happened a collision of cars three times on the nearby road.

B: Last year we saw a collision of cars three times on the nearby road.

Are both grammatically and semantically OK?

Can “a collision of cars” be replaced by “the collision of cars” in both sentences?

A. last year three cars collided on the nearby road.

B. Last year we saw three car collisions on the nearby road.

These do not mean the same. In A there was one collision involving three cars. In B there were three separate collisions involving an unstated number of cars each time.

— Thank you Beeesneees. I see your idea.
There is one more question. Is C wrong?

C: Last year we saw the collision of cars three times on the nearby road.

I think “the collision” means a specific one time event, so it can’t coexist with “three times” Am I right?

It’s very awkwardly worded (and ‘a’ would be better than ‘the’ there), but is not wrong simply because of the reason you suggest,

There were (car) collisions three times on that road last year.

is okay (though as I’ve explained it can be better worded). It is clear that there were three separate collisions over the period of the year.

Thank you Beeesneees.