In that respect, then, we also know that people have various tolerances to noise. Some people can sleep on a picket fence and some can't.
Would there not also be some utility in looking at real estate transactions and have some notice on a house listing that says that is on a flight path and that the people need to be aware of that? Far too often, people will move into an area without really understanding the dynamics of noise, be it from a rail switching yard to a truck route to a fly-over. Should that not also be part of the mix, as we look to try to mitigate the existing situation?