
Anna, I have some comments on your translation:
⦿ "When I walked" sounds like каждый раз, когда я ходил. In this post, the speaker was actively walking on one occasion, so we say "as I walked" or "when I was walking."
⦿The subject of this sentence is *I*, so you have put a comma after everything that comes before it: As I walked along the road,<[comma] I..."
⦿ THE links qualities and traits to their owner, so if you say "the endless traffic jam," then that means that that place always has a traffic jam as a constant feature. Maybe that's what the Russian implies, in which case, your translation is correct. But if the speaker just looked up and saw that there was a traffic jam that day, then it's AN endless traffic jam.