 |
Re: Wake up little people - HSR can be very loud
Author: BJ Hunnicutt
Date: 07-22-2017 - 13:25
> Sound pressure measurements mean nothing without a distance
Unless that is, you are a nimby or a pandering politician, or a grafty sound wall constructor feeding at the public trough.
Fact is, that when sound measurement distances are reported with multiple measurements spaced out at regular distances away from a potential noise source; the effectiveness of most sound walls diminishes by the square of the distance. In other words, they only have marginal benefit to a few right up close - within 100 ft - if that.
But of course, their multi-million-dollar per mile price tag is definitely "enjoyed" by many - by all actually. Not only that - they ruin many a ride that would otherwise be pleasant and comfortable.
In my neck of the woods, the light rail is quiet - significantly quieter than other street noise such as cars and trucks. You usually cannot hear the RT if there are any cars moving nearby.
But that didn't placate the nymby panderers one bit - the sound walls went up on some private r.o.w. anyway; significant stretches of 14ft walls very close on both sides of the tracks, making the ride almost dizzyingly unpleasant. Subsequent sound measurements suggest that these walls actually are amplifying the noise - especially on board - much like a subway would do. They were a mistake.
The natural sound levels of our RT passing by cannot be heard inside a house at all, with or without the walls. But the worst problem is that the walls were built right up against the tracks (no survivable space between wall and track); extending right to the edge of the sidewalk at grade crossings. There is no visibility whatever - not even enough to peak around to see if a train is coming or not. This lack of visibility resulted in numerous pedestrian deaths the first couple of years; especially at un-signaled ped crossings.
They had to tear them down for quite some distance at each grade crossing to provide even minimum visibility, before the ped deaths stopped. They might just as well tear down the rest.
And all this just to pander to NYMBYs, their lawyers, and grafty public trough feeders.
Unless that is, you are a nimby or a pandering politician, or a grafty sound wall constructor feeding at the public trough.
Fact is, that when sound measurement distances are reported with multiple measurements spaced out at regular distances away from a potential noise source; the effectiveness of most sound walls diminishes by the square of the distance. In other words, they only have marginal benefit to a few right up close - within 100 ft - if that.
But of course, their multi-million-dollar per mile price tag is definitely "enjoyed" by many - by all actually. Not only that - they ruin many a ride that would otherwise be pleasant and comfortable.
In my neck of the woods, the light rail is quiet - significantly quieter than other street noise such as cars and trucks. You usually cannot hear the RT if there are any cars moving nearby.
But that didn't placate the nymby panderers one bit - the sound walls went up on some private r.o.w. anyway; significant stretches of 14ft walls very close on both sides of the tracks, making the ride almost dizzyingly unpleasant. Subsequent sound measurements suggest that these walls actually are amplifying the noise - especially on board - much like a subway would do. They were a mistake.
The natural sound levels of our RT passing by cannot be heard inside a house at all, with or without the walls. But the worst problem is that the walls were built right up against the tracks (no survivable space between wall and track); extending right to the edge of the sidewalk at grade crossings. There is no visibility whatever - not even enough to peak around to see if a train is coming or not. This lack of visibility resulted in numerous pedestrian deaths the first couple of years; especially at un-signaled ped crossings.
They had to tear them down for quite some distance at each grade crossing to provide even minimum visibility, before the ped deaths stopped. They might just as well tear down the rest.
And all this just to pander to NYMBYs, their lawyers, and grafty public trough feeders.
