The hotel is situated at the very traffic-heavy corner, where some trains also pass just few meters from your room. And as the hotel is not sound-isolated, you can hear all those cars and trains just inside in your room. (I don't know how, but those Polish trains sound like airplanes. And if you close your eyes, you can imagine some airplanes take-off just from your room). You can also hear people who stay in rooms next to your room. But compared to traffical noise, it's just nothing. I will never ever stay at that hotel. And if you want to sleep during your stay in Warsaw, avoid that hotel by all means.