I-10 Twin Peaks Traffic Interchange, Environmental Assessment

Wall to
Protect
Rec. ID
Affected Environment and Environmental Impacts October 2005
Total
Units
(Benefited)
Table 4-8. Noise Mitigation Evaluation Summary
2030
Unmiti
-gated
Noise
Level
(dBA)
2030
Mitigated
Noise
Level
(dBA)
Barrier
Insertion
Loss
(dBA)
Barrier Dimensions Barrier Segment Costs
Approximate
Length
(feet)
Height
(feet)
Total
Cost
($20-25
/square
foot)
Cost per
Benefited
Receiver
LVR14 5 64 59 5 463 10 $92,600 $18,520
LVR15 64 59 5
LVR16 1 64 Single isolated receiver – no barrier recommended
LVR21 1 67 Single isolated receiver – no barrier recommended
Note: Recommended walls are indicated by bolding
Conclusion
Figures 4-4a through 4-4d illustrate locations where walls would be constructed to
protect impacted receivers. Although 49 of the 126 receiver locations were
predicted to meet criteria for consideration of noise mitigation in the 2030 build
condition, 11 of these locations were commercial properties; therefore, noise
mitigation for these 11 properties was not considered. Noise barrier walls were
analyzed in 13 locations to protect impacted residences. Of these locations, 6 walls
would protect single isolated residences and would not be constructed per ADOT
policy. One wall would protect three residences at a cost of $51,500 per residence;
therefore, this wall was determined to not meet ADOT’s cost per benefited
receiver criterion and was not recommended. Six locations were recommended for
the construction of noise abatement walls. These six walls would protect a total of
34 residences and would meet ADOT’s cost per benefited receiver criterion.
Although the Town intends to construct these walls as described above, the final
decision would be made following the public hearing process and discussions with
affected property owners. The design parameters of these walls would be
determined during final project design.
In addition to mitigation using noise walls, resurfacing Twin Peaks Road west to
Silverbell Road with RAC is proposed also. This treatment would improve
drivability of the roadway and decrease the noise generation from the tire-pavement
interface. Although the FHWA would not participate in the funding of roadway
resurfacing with RAC, the Town of Marana would fund this overlay.
Hazardous Materials
It is important to locate sites of soil or groundwater contamination before
performing construction activities. These contaminated properties could pose a
physical danger to construction crews or be liabilities if construction causes
contamination to migrate. To determine the potential of soil or groundwater
Interstate 10 Traffic Interchange at
Twin Peaks/Linda Vista
4-63
Project No.: NH-010-D (AIW)
TRACS No.: 10 PM 236 H5838 01D