Learn Hardcore Korean: gyotongsagoga namyeon gyeongcharege baro singohaeya haeyo. - If a traffic accident occurs, report it to the police immediately.

Breakdown of gyotongsagoga namyeon gyeongcharege baro singohaeya haeyo.

Why is it 교통사고가 나면 and not something like 교통사고를 나면?

Because 나다 is an intransitive verb, so the accident is treated as the subject, not the object.

A very literal breakdown is:

English often says have an accident, but Korean commonly says an accident occurs:

So 교통사고를 나다 would not be correct here.

What does 나다 mean in this sentence?

Here, 나다 means to occur, to happen, or to break out.

This verb is used in many expressions where something comes up or happens unexpectedly. For example:

So in 교통사고가 나면, 나다 does not mean to come out in the physical sense. It means that a traffic accident occurs.