Nobody has mentioned that the home in question has a shared driveway with the home right next to it.

From listening to friends who have had that situation, that will cause you more grief than the freeway noise.

So here is what we have: freeway noise, shared driveway, undetermined future construction (apts? condos? businesses? sfr?) directly behind….this taken together probably explains the length of time on market. One of those three probably spooks any potential buyer.