I made the mistake of buying a new duplex just 30 feet away from a road
where vehicles routinely pass by at 40+ mph every few minutes. I did
check the noise level before buying the house but my test case only
consisted of one car passing by at 25 mph. Plus the AC was on which
significantly damped out the sound ;-(

I spoked to some neighbours and they do not seem bothered by noise. I
suppose to each their own. I was hoping it bothered them too so we
could request the condo association to put up some kind of fence.

I did a google search and it seems I can reduce noise quite a lot by
doing some window "treatment". I have read about all sorts of things
from triple pane windows to interior windows to window plugs.

My question is there something really cheap I can build from materials
at Home Depot to see if this has potential? I thought I could buy some
half-inch plywood sheet, place it in the window frame and seal it with
old clothes.

What do you think?

Thx!