Why only truck noises seem to come through your double-paned windows

Windows that let in truck noises more than others aren't necessarily because the glass is thin. It's because the two panes of glass and the air between them act like two springs connected together. When a specific low frequency hits, both panes vibrate in unison, passing the sound through. That's why modern apartments add an extra window frame instead of just making the glass thicker. Homes that removed the inner window when expanding their balcony have lost that extra layer. If you open your living room window right now, you'll immediately know which side of the building you're on.