The February-March edition of the Little Canada Le Petit Canadien mentioned that about $250,000 will be made available for landscaping to recover some of the damage done by the increased width of the freeway and to moderate some of the noise that came with that freeway traffic. All I can say is, "it's about time." I've monitored the sound pressure level in my backyard during rush hour and the noise level far exceeds EPA and OSHA safe limits; well into the low 90dBSPL territory.
The Canadien article suggested that the City Council has "focused on the area between I-35E and West Savage Lake in an attempt to create some natural barriers to the sound and view coming from the freeway." This is a solid approach. The extended barriers on the east side of the lake have reflected additional noise in our direction, which makes safely enjoying our neighborhood and yards impossible during much of the day. Hopefully, the character MnDOT used as an "acoustic expert" won't be involved in this analysis, since pretty much all of his guess-timates about the effects on our neighborhood from the freeway expansion and the noise barriers were so far off I'd be surprised if that guy ever attended a science class at any time in his life.
Sound absorption is a much better tactic for silencing noise than obstruction. The noise barriers have a limited effectiveness, based on height, length of the barrier, distance from the noise source and the target clients, the noise bandwidth, and the mass of the materials used for the barrier. Absorption actually converts sound energy to heat; not a lot of heat, but that energy is no longer sound. Noise doesn't bounce off of conifers. Instead, the air motion pass through the branches and leaf tissue and moving those obstacles converts sound to motion and heat.
Of course, the trees will absorb some of the carbon dioxide, lowering pollution levels. In all, this is a plan my wife and I have been advocating for almost a decade and I'm glad to see the city and state buying into it. We should all give Joel Hanson a call at 651/766-4040 or email at email@example.com and get the city behind this idea. With decent sized plantings, almost immediately we could have a substantially more quiet neighborhood. In a few years, this could be our view of the freeway.