2.A. Topographical Concerns • The site plan, including but not limited to
The Project property and surrounding areas are project buildings, spectator stands and garage
not highly developed and include varying topographi- areas, was then imported and placed on the
cal features, for which the model considers when project site relative to the ground. The build-
calculating acoustical barrier effects. The topography ings were placed relative to the digital terrain
varies from a minimum of 460 feet at the northwest- foundation with the height of the roofs inter-
ern border of the project near residents to a maximum polated from the first/last point. (Improper
peak of 860 feet at the southeastern extremes of the placement, with an absolute height or ground
project, abutting the Interstate. The isometric view of at every point, will result in and uneven roof
the Project site and surroundings in Figure 2 empha- when the ground is not flat.)
sizes the potential significance of such topographical
details on the Cadna/A model. The contour of the terrain determines the aver-
age height of the sound ray and ultimately the ground
attenuation of the Project area. Fitting the road
course to the digital terrain model not only accurately
depicts the greatly anticipated “elevation changing”
track design by Formula 1 racing legend Derek Daly,
but allows for more realistic evaluation of natural
sound barriers and absorbers to be factored into the
sound propagation calculation.
While there are as many as nine track layouts cur-
rently contemplated from the planned construction,
the study considered only the “Track 2” configuration
(3.27 miles, 21 turns), which forms a perimeter enclos-
ing the largest geographical area and therefore locates
Figure 2. Isometric 3D image of Project site and Galla-
mobile sound sources nearer to the Project boundar-
tin County, KY vicinity
ies. Additionally, based on lengths and quantities of

straight-aways, Track 2 appears to be one of the top
URS received 10-meter digital elevation models
three tracks having high road speeds that, in turn,
(DEMs) in State Plane North and South Coordinate
should exhibit mobile source sound power levels that
Systems. Although nearly twice as large in terms of
are higher than those on the smaller tracks.
data file size, the ESRI Grid format was preferable over
the USGS format in defining a single zone to span the
2.B. Ambient Noise Sources
many acres of the Project. The following steps were
In the absence of validated field measurements,
followed in laying out the topographical foundation
the Federal Transit Administration (FTA) Transit Noise
upon which the model would be built:
and Vibration Assessment guidelines
2
were used to
estimate existing ambient sound level near an inter-
state highway and based on population density associ-
• The aerial was provided by the National
ated with rural land use. Unsurprisingly, noise levels
Agricultural Imagery Program (NAIP), a sub-
from I-71 were considered the dominant existing
sidiary of the USDA, who provides free aerials
ambient sound source, and relevant traffic data was
of the entire country. NAIP image databases
available to prepare both Cadna/A and TNM predic-
are administered / distributed by each state
tion models. Output sound levels from TNM for I-71
and therefore will have different channels to
were found to reasonably agree with the Cadna/A
access them. NAIP provides 1 meter ortho-
prediction.
rectified to a horizontal accuracy of within +/- 3
meters of reference digital ortho quarter quads
(DOQQs). NAIP quarter quads are rectified to
the UTM coordinate system NAD83.
The Official Magazine of the NSBE Alumni Extension November 2009 | Alumni Arsenal • 21
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42