I-10 Twin Peaks Traffic Interchange, Environmental Assessment

Affected Environment and Environmental Impacts October 2005
within the model to accommodate areas where the roadway climbs and traffic
volumes and speeds differed. Roadway geometry, topography, and receiver
locations and elevations were established from MicroStation plan sets from project
design engineers and PAG aerial photos and digital terrain model files.
One hundred twenty-six representative properties throughout the study area were
selected as model receiver locations (see Figures 4-4a-d). Residences and
businesses within the study area were chosen as representative sensitive noise
receivers and STAMINA was used to estimate the noise levels at these receiver
locations under existing (2004) traffic and under predicted conditions (2030). The
results of the analysis are presented in the table in Appendix C. Noise receivers
were designed as NR# along the north side of Twin Peaks Road, RS# along the
south side of Twin Peaks Road, I10F# in the area of I-10 and its frontage roads, or
LVR# along Linda Vista Boulevard.
Impacts
No Build Alternative
The noise monitoring and modeling analyses suggested that the NAC are exceeded
at a number of locations within the study area. Because traffic noise levels are
dependent upon traffic volumes, and traffic volumes are predicted to increase in the
area, noise levels would increase also. As a result additional properties in the project
area would be impacted by traffic noise regardless of whether or not the project is
constructed. According to the table in Appendix C, the entire area near I-10 (all
receivers beginning I10F#) exceeds the NAC under current conditions. All
modeled locations in this area are commercial land uses. Although one residential
property exists within this area, this residence would be acquired by the proposed
improvements; therefore, this residential site was not modeled. With the exception
of this area near I-10, only one other receiver (LVR12) within the study area
approached or exceeded the NAC for the year 2004. This receiver, located at the
intersection of Linda Vista Boulevard and Manatee Drive is adjacent to Linda
Vista Boulevard and substantially lower in elevation than the roadway. This
residence (as opposed to most in the area) is not separated from the roadway by a
wall. It is reasonable to assume that, with additional traffic growth, additional
residences in this area would exceed the NAC.
Preferred Alternative
Temporary Impacts
Construction noise differs from traffic noise in several ways:
• Construction noise lasts only for the duration of the construction contract,
and it is usually limited to daylight hours when most human activity
occurs.
• Construction activities generally are of a short-term nature, and depending
on the nature of construction operations, it could last from seconds (e.g., a
truck passing a receiver) to months (e.g., constructing a bridge).
Interstate 10 Traffic Interchange at
Twin Peaks/Linda Vista
4-51
Project No.: NH-010-D (AIW)
TRACS No.: 10 PM 236 H5838 01D