Just got the Audiophiles masters 1 from octave records. The track Saffron has this “garbage truck outside” sort of sound that made me pause the music more than once wondering if the trash truck was here 
What is that? An instrument? Or am I hearing the trash truck from Boulder, CO? 
Several people have brought that up. It’s why I like that track. It’s an instrument though not of the traditional kind. I can’t remember the name of it but it too was driving someone else nuts because they kept thinking something was happening outside their house. Love it!
(P.13 of the booklet)
The “truck drives by sound” might be the “…
Bull-roarer , pseudomusical instrument or device that produces a howling or whirring when whirled through the air…” Bull-roarer | musical instrument | Britannica
P.S. there is another track on the album recorded differently…. Will let you to find out. 