Can we PLEASE cut down the noise?

Soon after my family and I had moved to the USA, we noticed something which had registered with me only subconsciously during some of my former visits to the country: 

Americans seem to be much more tolerant of noise than Europeans (those that we know, anyway).

This can be seen in the following examples:

• Highways cut right through residential areas.
• The windows in the places we looked at before we found our current home are all quite shabby, you can hear the traffic from miles away (esp. from aforementioned highways)
• The forced-air heating many places use makes a terrible racket – we had to turn it down in our bedroom because we couldn’t sleep.
• Very many cars emit a loud beeping noise when backing up; I can understand the desire to have this in a trailer or truck that’s half a mile long, but in a pickup?

Needless to say, this is not the case in the places I lived at before we moved, so some adapting has been going on. Luckily, our kids seem to be very good at this; I don’t get the feeling that the noise is causing them to lose any sleep.

I would like to know though if anybody can come up with a good explanation for the above observation. I don’t think that American ears are inherently less sensitive than ours, so there must be a more complex answer …