I-10 Twin Peaks Traffic Interchange, Environmental Assessment

Affected Environment and Environmental Impacts October 2005
Construction noise is intermittent and depends on the type of operation, location,
and function of the equipment, and the equipment usage cycle. Traffic noise is
more continuous after construction activities are completed.
Permanent Impacts
Predicted noise levels assuming completion of the preferred alternative may be
found in the column labeled Modeled Future (2030) in the table in Appendix C. Of
the 126 modeled receivers, 49 were predicted to experience noise levels that would
require consideration of traffic noise abatement. The results of the modeling for
the future condition are divided by area and discussed in the following sections.
Twin Peaks Road (Receivers noted as NR# and RS#)
As would be expected, adding a new segment of Twin Peaks Road to connect to
I-10 increases traffic substantially through Continental Ranch and results in traffic
moving through an area where no traffic exists currently. As a result of this
increase in traffic and the new roadway, noise levels are predicted to increase
along Twin Peaks Road. As shown in the table in Appendix C, the increase in
traffic noise levels ranges from 6 dBA to 18 dBA. The areas of higher increases
were those areas on the east side of Continental Ranch where no roadway exists
currently (NR26-NR32A and RS27-RS30).
Although STAMINA did not predict that traffic noise levels would approach or
exceed the NAC (64 dBA or higher for the residences and other sensitive land uses
in this area), substantial increases (15 dBA) in noise levels were predicted. These
increases are predicted along the eastern border of Continental Ranch both north
and south of Twin Peaks Road.
Twin Peaks Road TI area (Receivers noted as I10F#)
STAMINA predicted increases in traffic noise in this area as well. However,
because traffic noise levels and traffic volumes are already high in this area, the
predicted increases were much lower than along Twin Peaks Road. In this area
traffic noise level increases ranged from 4 dBA to 5 dBA; however, all modeled
receivers in this area approached or exceeded the NAC (69 dBA or higher for
commercial properties).
Linda Vista Boulevard (Receivers noted as LVR#)
Although no improvements to Linda Vista Boulevard are proposed throughout the
majority of the study area, the provision of a Twin Peaks Road TI, would result in
increased traffic along Linda Vista Boulevard. To fully explore traffic noise
impacts, traffic noise levels were modeled as far east as Thornydale Road (nearly 4
miles east of the Twin Peaks Road TI). As a result of the increase in traffic,
STAMINA predicted increases in traffic noise levels ranging from 2 dBA to 14
dBA. Because of this wide range in values, these areas are discussed individually
below.
Interstate 10 Traffic Interchange at
Twin Peaks/Linda Vista
4-52
Project No.: NH-010-D (AIW)
TRACS No.: 10 PM 236 H5838 01D