HomeMy WebLinkAbout20240614 Lexington Road Subdivision Area Variances Second Supplemental Noise Report 07162025
July 16, 2025
Mr. Dominick F. Arico, PE
Arico Associates Engineers, Land
Planners, and Consultants
1407 Route 9, Building 2-Suite 6
Clifton Park , New York 12065
RE: Professional Consulting Services – Sound Study. Bemis Point Residential Subdivision
File: P703.5095
Dear Mr. Arico:
Barton & Loguidice, D.P.C. (B&L) is pleased to provide this additional information regarding Noise Walls and
Logarithmic functions of sound analysis.
The Scope of Work includes:
Noise Barriers:
Noise barriers are solid obstructions built between the highway and homes along a highway. They do not
completely block all noise — they only reduce overall noise levels. Effective noise barriers typically reduce noise
levels by 5 to 10 decibels (dB), cutting the loudness of traffic noise by as much as one half. For example, a barrier
which achieves a 10-dB reduction can reduce the sound level of a typical tractor trailer pass-by to that of an
automobile. Barriers can be formed from earth mounds or “berms” along the road, from high, vertical walls, or
from a combination of earth berms and walls. Earth berms have a very natural appearance and are usually
attractive. They also reduce noise by approximately 3 dBA more than vertical walls of the same height. However,
earth berms can require wide swaths of land to construct, especially if they are very tall as the footprint of a 10’
high berm would be 40’ wide at the base using the steepest of slopes recommended (1’vertical to 2’ horizontal).
Walls require less space, but they are usually limited to 25 feet in height for structural and aesthetic reasons.
In this particular case, sound levels from traffic along I-87 are expected to increase from 0 and 1 dBA. Important to
remember that this change is not going to be noticeable to human hearing as human hearing begins to discern
changes in sound when sound levels are different by 3 dBA. Laboratory instruments cannot discern changes in 1
dBA. A sound barrier to mitigate a sound change that is not noticeable, as shown in the analysis, is not considered
practical by NYSDOT, the NYSDEC and the Federal Highway Administration. Disturbances from construction and
the reduction in the tree line to build such a structure will also reduce any benefit from the construction of a wall in
this location.
To effectively reduce the noise coming around its ends, a barrier should be at least eight times as long as the
distance from the home or receiver to the barrier (Source FHWA). In the case of the subject proposed project, this
length would be 450’ x 8 = 3,600’ extending 1,100 feet north of Route 29 (Lake Avenue) to the U-turn on I-87
southbound or 1000’ from Exit 14. Sound barriers along an Interstate Highway will range in costs from $50 to $100
a square foot in New York State (Source FHWA). A noise barrier along I-87 northbound in the Town of Colonie
beginning at the north end of Wolf Road was constructed at a cost of $58 a square foot in 2019 (not including
earthwork or property costs - Source NYSDOT, FHWA). A 3600’ foot wall at a height of 10’ at an inflation adjusted
2025 cost of $75 a square foot. Keep in mind, this wall would be reducing existing sound levels that are there and
will still be there whether the proposed project is constructed or not.
Sound Pressure Logarithmic Scale and and Truck Exhaust Brakes
Sound levels are derived from sound pressure and expressed in decibels. Sound pressure increases on a
logarithmic scale.
Decibels (dB) use a logarithmic scale, to represent a wide range of sound intensities or other quantities. This means
that each increase of 10 dB represents a doubling of the sound levels. This allows the decibel value to represent a
very wide range of sound intensities (from barely audible to extremely loud) on a scale that is manageable and
easier to understand. For example, a whisper might be 30 dB, while a loud rock concert could be 120 dB,
compressing a vast range of intensities into a scale from 0 to 140 dB. Louder sound levels such as an exhaust brake
(a.ka. Jake Brake) can be between 80 decibels and 100 decibels at a distance of 50’. The nearest residence along
Lexington Road to southbound I-87 is located approximately 320’ from the travel lanes. Assuming a 90 decibel
“Jake Brake” sound, the sound of the exhaust brake could be, using the inverse square law of sound propagation
and accounting for the vegetation, approximately 70 decibels at the nearest home. This sound level is greater than
the background noise from the trucks and vehicles travelling along I-87 (60 to 65 dBA) and is an existing condition
that will not change as a result of the proposed project. Due to the project, this specific burst of higher sound level
would result in an increase of 1 to 2 dBA at the existing residences along Lexington Road for this period. As traffic
noise is evaluated environmentally for a one-hour equivalent period, this short burst would not impact the overall
1 hour equivalent level, but would show up in field measurements as an impulse peak or maximum recorded level.
If you have any questions, please do not hesitate to contact me at our Albany Office at (518) 218-1801
extension 2016, or by cell phone at (518) 423-1062.
Sincerely,
BARTON & LOGUIDICE, D.P.C.
Thomas C. Baird, P.E.
Sr. Associate