Q:

Should I let someone overtake my car if there is not enough space to do it?

This question came up in my driver license test (in Japan).
I found this question hard to answer because not allowing someone to overtake you may cause an accident (after all, you may be mistaken about the available space). However, if indeed there is no enough space, it may cause an accident.
I was unable to find the answer available in English here, so I'm guessing other countries may have similar rules.
The correct answer for this question will be a quote (and a link) to an official (or credible) source about this issue here in Japan or alternatively in any other country.

A:

I doubt that you will find an official answer to that question. No law allows you to block passing (even if passing is illegal). Therefore, you must allow passing. There are laws against obstructing traffic. Japanese law addresses this, defining obstructing progress as

starting to move or continuing to move in circumstances that would
likely cause another vehicle or streetcar to have to suddenly change
speed or direction in order to avoid danger

You'd have to specify how you intend to "not let" a person pass you, but I can't imagine what you could do that would not be "obstructing progress". A recent anti-road rage law allows license revocation for violation.

