dorojuhaengsiheom ttae siheomgwaneun josuseoge anjseupnida.

It is a compound noun made of three parts:

• 도로 = road
• 주행 = driving / operating a vehicle
• 시험 = test / exam

So 도로주행시험 is literally something like road-driving test, which is why it means a road test or driving test on the road.

Korean often writes compound nouns as a single word when they function as one unit.

So:

• 도로 + 주행 + 시험 → 도로주행시험

This is very common in Korean. English often separates words more than Korean does, so this can feel strange at first.

때 means time, and after a noun it usually means when, at the time of, or during.

So:

• 도로주행시험 때 = during the road test / when taking the road test

This pattern is very common:

• 수업 때 = during class
• 시험 때 = during the exam
• 어릴 때 = when one was young

The particle 은/는 marks the topic, while 이/가 marks the subject more directly.

Here, 시험관은 sounds like the sentence is giving general information about what the examiner does in that situation. It has a descriptive, explanatory feel:

• 시험관은 조수석에 앉습니다. = As for the examiner, they sit in the passenger seat.

If you said 시험관이, it would put more focus on the examiner as the subject, perhaps as opposed to someone else.

In procedural or explanatory sentences, 은/는 is very natural.

시험관 means examiner or test official.

It is made from:

• 시험 = test
• 관 = official / person in charge

So this is the person who supervises or evaluates the test.

조수석 means the front passenger seat.

Literally:

• 조수 = assistant/helper
• 석 = seat

So the literal sense is something like assistant seat, but in normal English translation it is simply the passenger seat or more specifically the front passenger seat.

Because 앉다 normally uses 에 to mark the place where someone sits.

So:

• 의자에 앉다 = sit on a chair
• 바닥에 앉다 = sit on the floor
• 조수석에 앉다 = sit in the passenger seat

English speakers often expect something like 에서, but with 앉다, 에 is the normal choice.

In Korean, the present tense is often used for:

• habitual actions
• general facts
• instructions
• what normally happens in a situation

So 앉습니다 here does not necessarily mean is sitting right now. It means something more like:

• sits
• will sit
• is seated
• normally sits

In context, it describes the standard procedure during the road test.

앉습니다 is in the formal polite style.

This style is common in:

• official explanations
• manuals
• tests
• announcements
• formal writing

The same verb in other styles would be:

• 앉아요 = polite, less formal
• 앉아 = casual

So the sentence could also be said as:

• 도로주행시험 때 시험관은 조수석에 앉아요.

But 앉습니다 sounds more formal and appropriate for instructional or official language.

This is due to Korean pronunciation rules.

Although it is written 앉습니다, it is pronounced roughly like 안씀니다.

What happens is:

• the final consonant cluster in 앉- is simplified in pronunciation
• the ㅅ in 습니다 becomes tense after that environment

So learners often notice that the written form and spoken form do not match exactly. That is normal in Korean.

Yes. Korean word order is more flexible than English as long as the particles make the roles clear.

For example, this is also possible:

• 시험관은 도로주행시험 때 조수석에 앉습니다.

This has almost the same meaning.
The original sentence puts 도로주행시험 때 first, which makes the time setting clear right away. That is a very natural way to organize the sentence.