chaseon yeopui gyotong pyojipaneul bwassseupnida.

차선 means a traffic lane or lane of a road—the part of the road where cars travel. It does not usually mean the painted line itself. If you want to talk about the line, Korean would more likely use something like 차선 표시 or another more specific expression depending on context.

So in this sentence, 차선 옆의 means next to the lane.

옆 means side or next to.
The particle 의 turns the noun phrase before it into something that modifies the next noun.

So:

• 차선 옆 = the side of the lane / beside the lane
• 차선 옆의 교통 표지판 = the traffic sign beside the lane

In English, this works a bit like saying the sign that is next to the lane.

Good question. 옆에 usually marks a location in a full clause, while 옆의 directly modifies a noun.

Compare:

• 차선 옆의 교통 표지판 = the traffic sign next to the lane
• 차선 옆에 있는 교통 표지판 = the traffic sign that is next to the lane

So 옆의 is a shorter noun-modifying form.
If you use 옆에, you usually need something like 있는 after it to connect it to the noun naturally.

It is best understood as a noun phrase made of:

• 교통 = traffic
• 표지판 = sign / signboard

Together, 교통 표지판 means traffic sign or road sign.

A learner can think of it like an English compound noun: one noun describing another. Korean often builds vocabulary this way.

을/를 marks the direct object of the verb. It tells you what was seen.

So in this sentence:

• 교통 표지판을 = the traffic sign as the thing being looked at / seen
• 봤습니다 = saw

Because 표지판 ends in a consonant, the correct object particle is 을, not 를.

Korean normally uses Subject-Object-Verb order, so the verb usually comes at the end.

This sentence is structured like:

• 차선 옆의 교통 표지판을 = object phrase
• 봤습니다 = verb

That is very normal Korean word order.
For English speakers, this can feel backward at first because English usually puts the verb earlier.

봤습니다 is:

• past tense
• formal polite style

It comes from the dictionary form 보다 = to see

So 봤습니다 means saw in a polite, formal way.
This style is common in formal speech, presentations, reports, announcements, and respectful conversation.

봤습니다 is the contracted form of 보았습니다.

The verb is 보다. In the past tense:

• 보았습니다 is the full form
• 봤습니다 is the shortened, very common form

Both are correct.
In everyday Korean, the contracted form 봤습니다 is much more natural and common.

The subject is omitted, which is very common in Korean.

Korean often leaves out the subject when it is already clear from context. So this sentence could mean:

• I saw the traffic sign
• We saw the traffic sign
• He/She saw the traffic sign

The exact subject depends on the situation.
This is one of the biggest differences from English, where subjects usually need to be stated more explicitly.

Yes. That would also be natural.

• 차선 옆의 교통 표지판을 봤습니다
• 차선 옆에 있는 교통 표지판을 봤습니다

Both mean essentially the same thing: I saw the traffic sign next to the lane.

The second version is a little more explicit because 있는 literally adds the idea of that is located next to the lane.
The version with 옆의 is shorter and more compact.

In this sentence, 보다 is best understood as to see or to look at, depending on context. Korean 보다 covers a range that in English is split across several verbs.

So 표지판을 봤습니다 can mean:

• saw the sign
• looked at the sign

If the larger context is not given, English may choose one or the other. Korean itself is perfectly natural either way.