Let's face it, you are missing a lot of opportunities just because you really think is not the good time to approach that girl. One of the most common excuse is when she is waiting for something, in this case, a bus, a lot of guys will say "she is busy", "oh no, i cannot do it", and they may be right but not entirely.

Actually you should have some social intelligence for this kind of situations, first, assume her time is limited, so do not try to engange in a super deep conversation, you never know when she is leaving, and secondly, close number as fast as you can, I know this is far from being solid, but keep in mind once again, you have no time, and the last thing you want is a great conversation and girl vanishing away just because suddenly she had to run away and you forgot to get her number.

And as a reminder, your chances are actually very low due to the difficult situation you are trying to know her, she will be more concentrated into getting her bus, but , you never know, even from some weak approach, later on can lead to an amazing date or even more.

If you want to watch an infield with exactly this situation or check more details, check the following link:

https://www.youtube.com/watch?v=uJX8Bz6ryiU

Greetings

Joan