[fit2rule]

The sentence: "yes, because we are actually stopping at them" is in reference to the subject: "the traffic lights". The originator of the sentence was intending to convey the meaning that Germans - in general - stop at the traffic lights, whereas non-Germans, generally, do not.

Ask yourself this question: Are they stopping at the traffic lights right now in the present-progessive sense? Is the speaker talking about doing this 'right now'?

http://www.englisch-hilfen.de/en/grammar/pres_pro.htm

.. or is it .. in the Simple Present form?

http://www.englisch-hilfen.de/en/grammar/simple_present_form...

[michaelmior]

Based on your link, use number 4 of the present progressive fits the OP's original statement: "actions happening around the moment of speaking (longer actions)"

[fit2rule]

In that case, the sentence would be properly formed thus:

"The Germans do stop at traffic lights. Non-Germans, do not."

Notice the difference?

Final Edit: the German-formed sentence I was correcting:

    "Yes, because we (Germans) are actually stopping at them!"

.. becomes:

    "Yes, because we (Germans) do actually stop at them."

Now, we can certainly look at the downvotes I've earned as a result of my personal foul use of language, but for the German-native speakers who make this mistake, it makes a huge difference in how well they are, actually, understood by English visitors. Please re-read, and see for yourself.

[PavlovsCat]

This is off-off-topic, but I wish forums allowed users to state that they would be happy to have their grammar and spelling corrected by ticking a checkbox, and that every comment could have a sub-discussion just for that, on its own page. That would be useful, or? (<-- joke :P) Because otherwise whatever you do, it's wrong: making a correction makes you seem like a jerk, and not making a correction makes you feel like a jerk (because you know something they don't, and you're not sharing it).