Do you have experience with how the noise pollution changes when the area is developed or how this pollution feels?
We live about 500mm from the A7. With the right wind, you can also hear it here as a slight rustling. You can hear loud individual cars too, as already mentioned. In my opinion, you don't really notice it.
Being developed also makes a difference: it's louder in front of the house than at the back :D
I would try to get a plot on the far side... although, there are people here whose property ends right at the A7 - and they are still living fine ;)
Have you ever stood there during the day/night and listened? I did that back then and found that even 10km away (our previous apartment) you can still hear a slight rustling caused by the A7. Otherwise, you don't really notice it.