chaseoneul bakkugi jeone banghyangjisideungeul kyeogo sagakjidaereul hwaginhaessseupnida.

차선 means lane. The form 차선을 is 차선 + 을, where 을/를 is the object marker.

Here, 차선을 바꾸다 means to change lanes, so 차선 is the thing being changed and takes the object marker:

• 차선을 바꾸다 = to change lanes

In natural Korean, object markers are sometimes omitted in casual speech, but in a careful written sentence like this, 차선을 is completely normal.

바꾸기 전에 means before changing or before you change.

This pattern is:

• verb stem + -기 전에 = before doing ...

So:

• 바꾸다 = to change
• 바꾸기 전에 = before changing

The -기 turns the verb into a noun-like form, so literally it is something like before the act of changing.

Compare:

• 먹기 전에 = before eating
• 가기 전에 = before going
• 자기 전에 = before sleeping

This is a very common pattern in Korean.

Yes. 바꾸기 전 and 바꾸기 전에 are both used.

• 바꾸기 전 = before changing
• 바꾸기 전에 = before changing / before you change

In many cases, the difference is small. 전에 can feel a little more complete as an adverbial phrase meaning before doing something. In everyday Korean, both are common.

So these are both natural:

• 차선을 바꾸기 전 방향지시등을 켜세요.
• 차선을 바꾸기 전에 방향지시등을 켜세요.

방향지시등 is the formal word for a turn signal or indicator.

It breaks down like this:

• 방향 = direction
• 지시 = indication
• 등 = light

So literally it is something like direction-indicating light.

In everyday speech, many Koreans also say:

• 깜빡이 = blinker / turn signal

So:

• 방향지시등을 켜다 = to turn on the turn signal
• 깜빡이를 켜다 = to turn on the blinker

The sentence you gave sounds a bit more formal and standard because it uses 방향지시등.

켜고 is from 켜다 (to turn on) plus -고, a connector meaning and.

So:

• 켜다 = to turn on
• 켜고 = turn on ... and ...

In this sentence, -고 links two actions:

1. 방향지시등을 켜고 = turned on the turn signal
2. 사각지대를 확인했습니다 = checked the blind spot

So the sentence describes a sequence of actions connected smoothly:
turned on the signal and checked the blind spot.

In many cases, -고 can imply that the first action happens before the second, especially when the real-world order makes that obvious.

Not always strictly, but very often it does suggest that order, especially when the actions are naturally sequential.

In this sentence:

• 방향지시등을 켜고
• 사각지대를 확인했습니다

the natural interpretation is:

1. turned on the signal
2. checked the blind spot

Because those actions logically happen in sequence, -고 works well here.

But in other contexts, -고 can simply mean and, without strongly emphasizing time order.

사각지대 means blind spot.

It is made of:

• 사각 = dead angle / blind angle
• 지대 = zone / area

So literally it is something like blind area or dead-angle zone.

In driving, 사각지대 is exactly the blind spot around the car that you cannot easily see with mirrors alone.

확인했습니다 means checked or confirmed, and it sounds more precise and natural in this context than simply 봤습니다 (saw/looked at).

• 보다 = to see / look at
• 확인하다 = to check / verify / make sure

When talking about safe driving, Korean often uses 확인하다 because the point is not just looking, but making sure the blind spot is clear.

So:

• 사각지대를 봤습니다 = I looked at the blind spot
• 사각지대를 확인했습니다 = I checked the blind spot

The second one sounds more natural and responsible in a driving context.

확인했습니다 is the formal polite past tense of 확인하다.

Breakdown:

• 확인하다 = to check
• 확인했습니다 = checked / have checked

This style is called the 습니다-style, which is common in:

• formal writing
• instructions
• reports
• polite narration

So the sentence sounds formal and clear, which fits a driving-related explanation or textbook sentence.

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

From 확인했습니다, the sentence could mean something like:

• I checked
• we checked
• he/she checked (in some contexts, though this formal style often suggests the speaker or a written report)

In a textbook or example sentence, English often translates it with I if the context is a person describing their action:

• I turned on the signal and checked the blind spot before changing lanes.

But Korean does not need to state the subject if it is already clear from context.

As written, it describes something that already happened, because of 확인했습니다 (past tense).

So it is more like:

• turned on the signal and checked the blind spot

If you wanted to make it an instruction, you would change the ending, for example:

• 차선을 바꾸기 전에 방향지시등을 켜고 사각지대를 확인하세요.
  = Before changing lanes, turn on your signal and check your blind spot.

So the original sentence is a past-tense statement, not a command.

Yes. Both are possible, but they feel slightly different in tone.

• 바꾸다 = to change
• 변경하다 = to change / alter (more formal, Sino-Korean style)

So:

• 차선을 바꾸기 전에 = before changing lanes
• 차선을 변경하기 전에 = before changing lanes

바꾸다 is more everyday and conversational.
변경하다 sounds more formal, technical, or official.

In driving manuals or official instructions, 변경하다 might appear more often. In general learning materials, 바꾸다 is very common and easier to use.

The sentence can be divided into three parts:

1. 차선을 바꾸기 전에
   = before changing lanes

2. 방향지시등을 켜고
   = turn on the signal and / having turned on the signal

3. 사각지대를 확인했습니다
   = checked the blind spot

So the structure is basically:

• [Before doing X], [do Y] and [did Z].

Or more naturally in English order:

• Before changing lanes, I turned on the signal and checked the blind spot.

This is a very common Korean sentence pattern:

• time/background phrase first
• then connected actions
• final main verb at the end