HomeMy WebLinkAbout2007 08 13 Informational 103 Florida Turnpike's Draft Noise Study for Proposed SR 417 Widening Project
COMMISSION AGENDA
ITEM 103
INFORMATIONAL X
August 13,2007
Meeting
MGR/DEPT
Authorization
REQUEST: Public Works Department providing the City Commission with information
regarding the City's independent technical review of the Florida Turnpike's
Draft Noise Study for the proposed Seminole Expressway (SR 417) widening
project
PURPOSE: The purpose of this agenda item is to provide the City Commission with information
regarding the Seminole Expressway (SR 417) widening project
ISSUE OVERVIEW:
. Florida's Turnpike recently completed a Project Development and Environment (PD&E)
Study for the proposed widening of the Seminole Expressway (SR 417) from 4-lanes to 8-
lanes from the Orange/Seminole County line to the Rinehart Road interchange.
. A Noise Study was completed as a part of the PD&E Study by the Turnpike's engineering
consultant, PBS&J. The results of the Turnpike's noise study are summarized as follows:
o A sound wall will not be provided along the west side of the Seminole Expressway
where the roadway is adjacent to the City of Winter Springs.
o The Noise Study concluded that portions of the Winter Springs side of the
Expressway meet all technical criteria for warranting a sound wall; however, it does
not meet the minimum criteria set by FDOT for being cost effective.
o According to PBS&J, the maximum allowable cost per beneficiary for a sound wall
is $35,000. The cost per beneficiary for the impacted residences in Winter Springs is
$48,636. The noise-impacted subdivisions bordering the west side of the Seminole
Expressway (Chelsea Woods and Chestnut Estates) do not have a high enough
density to meet the maximum cost per beneficiary criteria.
o The City of Oviedo subdivision directly opposite of Chelsea Woods on the east side
of the Expressway has a higher density and a sound wall is planned along this side.
o The Turnpike's noise study will be reevaluated at the time the project moves into
final design for the widening to 8-lanes, which is not expected for up to 20 years.
Informational Agenda Item 103
August 13, 2007
Page 2 of3
. City Staff formally requested as a part of the Public Hearing record that a sound wall be
approved for the project along the west side of SR 417 from SR 434 to the southern
boundary of the City limits just south of Winter Springs Boulevard.
. Turnpike representatives have recently stated that the Seminole Expressway is scheduled to
be widened from 4 to 6 lanes from the Orange/Seminole county line to State Road 434
within the next five years. According to the Turnpike, the widening to 6-lanes is covered by
a previous PD&E Study, and no sound walls are required as a part of the 6-laning project.
The expansion to eight lanes is planned within the next 20 years. Sound walls approved as a
part of the current PD&E Study would only be constructed when the Expressway is widened
to 8-lanes.
INDEPENDENT TECHNICAL REVIEW:
In June 2007, the City hired Dr. John MacDonald ofthe UCF Community Noise Lab to perform a
technical review of the noise impact component of the Turnpike's PD&E report. Dr. Macdonald
reviewed the study methodology and the abatement options that were considered, including the
estimation of the number of benefited receivers and a review of the reasonableness criteria used to
determine whether noise abatement is appropriate. Dr. Macdonald also reviewed the Turnpike's
Traffic Noise Model used to predict sound levels and noise barrier impacts. Dr. MacDonald is
highly familiar with highway noise barriers and specifically the Turnpike's methodology for
conducting noise studies. A copy of his report is attached as Exhibit A.
Dr. MacDonald's review concluded that the Turnpike's "reasonableness decision" to not provide a
sound barrier to the affected Winter Springs subdivisions should be reconsidered. This conclusion
was based primarily on the following findings:
1. The proposed noise abatement barrier along the affected Winter Springs subdivisions meets
the FDOT reasonableness criteria when using the standard barrier unit cost of $25 per square
foot as specified in the 2003 FDOT PD&E Manual.
2. The proposed noise abatement barrier along the affected Winter Springs subdivisions meets
the 2007 FDOT guidelines for cost per benefited receiver and square footage per benefited
receIver.
3. The Turnpike's approval ofa sound barrier on the east (Oviedo) side of the Seminole
Expressway should be given consideration in the reasonableness decision for a sound barrier
along the west (Winter Springs) side.
Dr. MacDonald's report was submitted to the Turnpike and their noise consultant, PBS&J, for
review on July 6,2007. A copy ofthe Turnpike's response letter is attached as Exhibit B.
According to the Turnpike, a right-of-way sound barrier, which is located near the edge ofthe right-
of-way away from the travel lanes, is subject to the standard barrier unit cost of $25/SF found in the
PD&E Manual. However, a shoulder noise barrier, which is proposed along much of the noise-
impacted area adjacent to Winter Springs, is located closer to the travel lanes and is subject to a
Informational Agenda Item 103
August 13,2007
Page 3 of3
variable unit cost based on the need to provide special design characteristics (more steel
reinforcement and larger foundations to withstand vehicle impacts). Along most of the Winter
Springs corridor a shoulder barrier is the only type of wall that is cost reasonable and would provide
the necessary noise reduction.
According to Dr. MacDonald, the PD&E Manual states that sound barrier costs include a variety of
things, but in the end it states a specific barrier cost of $25/SF to be used for noise studies after
October 1, 2000. The use of a standard unit cost straight from the manual is intended to avoid this
exact type of situation, where the use of more subjective units costs are used in part as a basis to
deny a wall that would otherwise be approved using the standard cost. It should be noted that for
the entire Seminole Expressway widening corridor, the proposed sound barrier adjacent to Winter
Springs is the only sound barrier that would change from denial to approval based on utilizing the
standard barrier unit cost of $25/SF as recommended by Dr. MacDonald.
The Turnpike identified passages in the PD&E Manual stating that noise barrier costs do not include
costs associated with right-of-way needs or special design considerations; however, the Turnpike
was unable to provide specific passages from the PD&E Manual supporting the specific unit costs
used in the SR 417 Draft Noise Study. The Turnpike has agreed in writing (see Exhibit B) to
reanalyze a noise barrier in this area during the design phase of the project.
ADDITIONAL INFORMATION:
Representatives from the Turnpike will be meeting with Chelsea Woods homeowners on September
17, 2007 to discuss the Seminole Expressway widening project.
ATTACHMENTS:
1. Exhibit A - Technical Review of Seminole Expressway Draft PD&E
2. Exhibit B - Florida's Turnpike / PBS&J response letter dated July 18, 2007
COMMISSION ACTION:
EXHIBIT A
Technical Review
of
Seminole Expressway Draft PD&E
Prepared for:
Brian Fields
City Engineer
City of Winter Springs
Winter Springs, Florida
Prepared by:
John M. MacDonald, Ph.D., P.E.
3142 Ash Park Loop
Winter Park, Florida 32792
July 5, 2007
Version July 30, 2007
1
Introd uction
This document summarizes a technical review of the Draft Project Development and
Environment Noise Study ofan expansion of the Seminole Expressway (S.R. 417)[1]. A
review was focused on the corridor between the Winter Springs Blvd. to S.R. 434 and
specifically reviewed the conclusions of the Draft PD&E in regard to noise impact and
abatement at communities located along this corridor. The Florida Department of
Transportation (FDOT) Project Development and Environment Manual [2][3] provides
the state policy for the noise portion of the PD&E and has recently been updated [3]. The
Noise Study information is contained in Part 2/Chapter 17 of the PD&E manual and
provides detailed policy information in regard to estimated barrier costs, and reasonable
costs per benefited receiver (CBR). The methodology and assumptions used in the Draft
PD&E were compared to guidance provided by the Florida Department of Transportation
PD&E Manual[2][3]. The review is summarized in the following sections.
PD&E Summary
The Draft PD&E Noise Study describes the noise impact from increased traffic sources
due to the widening the S.R. 417 Seminole Expressway. The area of specific interest for
this review is between the Winter Springs Blvd. and S.R. 434 roadways, between station
numbers 1510 to 1544. Table 1 summarizes the communities along this portion of the
corridor and contains results from the Draft PD&E [1] such as the estimated number of
impacted receivers and the approximate size and cost of a barrier to provide adequate
noise abatement for these communities.
Table 1. Modeled Barriers for Impacted Communities between the Winter Springs
Blvd. to S.R. 434 (these results are from the Draft PD&E [!l).
Community Number of Estimated Number of
d . Location benefited
as name lD impacted cost of .
PD&E (station) residences barrier reSidences
Cost per
benefited
receiver
($/receiver)
Seneca Bend
and
Tuscawilla
Communities
Oak Hill
Villas, Shed
Grove,
Worthington
151 0-
1544
30
$2,188,640
45
$48,636
(above criteria
value)
1520-
1581
65
$2,283,000
68
$33,574
(below criteria
value)
Communities on the east side of this corridor include the Oak Hill Villas, Shed Grove and
Worthington developments which have, according to the Draft PD&E, an estimated 65
residences that will be impacted by the widening project. A receiver is said to be
impacted if the predicted sound pressure level approaches an upper limit value [66 dB(A)
as defined in Florida] or ifit is predicted to have a substantial increase [15 dB(A)
increase as defined in Florida] due to the influence of the project [2][3]. A proposed
Version July 30, 2007
2
barrier to abate this impact will ultimately benefit an estimated 68 receivers resulting in a
cost per benefited receiver of$33,574 which is less than the upper limit of$35,000 stated
by Florida DOT [2].
Residential areas on the west side of the corridor include Seneca Bend and "Tuscawilla
Communities" which also includes Chelsea Woods. These communities are lower
density developments resulting in an estimated 30 impacted receivers. A proposed 14
foot shoulder barrier (and 8 foot structure barrier) will benefit 45 benefited receivers,
according to the Draft PD&E. This results in a cost per benefited receiver of $48, 636
which exceeds the FOOT upper limit of$35,000 [2].
This leads to a situation where the communities on the east side of this corridor are
eligible for a sound reduction barrier but similarly impacted communities on the west
side of the corridor are not.
The method used to estimate noise impacts and evaluate sound reduction barrier
effectiveness is based on the FHW A Traffic Noise Model [ 1]. The TNM models used in
the Draft PD&E were reviewed and these details are discussed in the next section.
TNM Model Verification
The FHW A Traffic Noise Model (TNM) [4] is the FDOT promulgated computer model
used to predict noise impact due to a highway project and to estimate which receivers
may benefit from the construction of a sound reduction barrier. A basic TNM model was
constructed as a check on the numbers reported in the Draft PD&E for the corridor of
interest. The Draft PD&E specifies traffic volumes and speeds for the existing case,
build and no-build future cases and also aerial photos of the corridor. These items make
it possible to construct a basic model of the corridor to verify the TNM reported hourly
Leq sound pressure levels. Large differences between the basic TNM model and the
Draft PD&E point to differences between the models and can serve as a guide to
investigate specific receivers.
Table 2 lists the Draft PD&E [I] receiver sound levels from the "Seneca Bend" and
"Tuscawilla Communities" for the existing case (2005) and the future build case (2035).
The table also contains the results from the "Basic" TNM 2.5 model and compares these
to the Draft PD&E results.
Table 2. Draft PD&E and Basic TNM model comparison (LeqAhr)'
Receiver Draft Basic delta, Draft Basic delta,
PD&E TNM dB(A) PD&E TNM dB(A)
2005 Existing 2035 2035
case model
model
61.2
62.7
61.2
64.4
RW95
RW96
RW96.1
RW97
62.5
65
60
64.7
-1.3
-2.3
1.2
-0.3
65.7
68.0
62.6
67.8
66.2
68.0
68.7
69.7
0.5
o
6.1
1.9
Version July 30, 2007 3
RW98 68.3 70.4 2.1 71.6 73.8 2.2
RW99 66.3 66.3 0 69.9 71.8 1.9
RW100 63.3 62.5 -0.8 66.8 69.1 2.3
RW101 62.1 61.1 -1 65.4 67.3 1.9
RW106 66.9 66.3 -0.6 70.1 71.8 1.7
RW107.1 62.7 63.4 0.7 66.4 68.7 2.3
RW108 62.4 62.7 0.3 66.4 68.3 1.9
RW121 56.9 57.1 0.2 61.3 63.9 2.6
RW122 58.5 59.3 0.8 62.3 64.6 2.3
RW124 60.6 60.4 -0.2 64.1 66.5 2.4
Table 2 shows good agreement between the basic model and the Draft PD&E results for
the 2005 case [average residual error = 0.8 dB{A)]. The relatively small error between the
Draft PD&E models and the simple model is primarily due to the simplicity of the terrain
in this area. These results deviate for the 2035 Build case where the basic model is
predicting between 2-6 dB{A) louder hourly Leq values than stated in the Draft PD&E.
The 1-2 dB (A) differences are primarily due to differences in source-receiver geometry
between the basic model and Draft PD&E but the large difference of 6.1 dB{A) was
further investigated.
The TNM input files used for the Draft PD&E were obtained and reviewed. The
differences in the RW96.1 were investigated and it was found that the ground elevation
of this receiver differed significantly from other receivers in the Seneca Bend
development. The modeling anomaly of the RW96.1 receiver was changed to reflect
ground elevations of nearby receivers (RW96.1 = 5 feet, RW96 = 38 feet and RW101 =
38 feet ground elevation) and this resulted in an additional impacted receiver for the
existing and future cases. This change did not affect the number of benefited receivers
for future case build model with the proposed sound barrier and therefore did not affect
the cost per benefited receiver value.
The TNM model of the build option with a shoulder barrier was modified for barrier
heights other than the 14 foot height stated in the Draft PD&E. Preliminary TNM results,
using the Draft PD&E TNM files, indicate that a 12 foot barrier is as effective as the 14
foot design with the exception of the RWI00 receiver [changes from a 5.1 dB{A)
insertion loss to a 4.6 dB{A) insertion loss]. Additional testing is required but this
indicates that a barrier optimization could result in an effective barrier with a total surface
area less than that proposed in the Draft PD&E. A lower total surface area of a barrier
translates to lower cost and lower cost per benefited receiver (assuming that the number
of benefited receivers does not change).
The TNM input files contain right of way (ROW) barrier designs in addition to the
proposed shoulder barrier. According to the Turnpike Enterprise, a ROW barrier is
subject to the unit cost found in the PD&E Manual ($25/sqt) whereas a shoulder barrier is
subject to a variable unit cost that includes additional safety features. The TNM input
files contain several ROW barrier designs and a review of them shows that the best case
scenario (smallest total area with a sufficient number of benefited receivers) still results
in a barrier that exceeds the cost criteria for the Seneca Bend/Tuscawilla communities.
Version July 30, 2007
4
Additional TNM modeling items were reviewed and Table 3 contains the results of the
reVIew.
Table 3. TNM Model review of the Seneca Bend and "Tuscawilla Communities."
Modelin2 Item Review Conclusions
Source location A review of the aerial photos indicates
that the existing and future case lane
locations appear accurate
Barrier length Review of aerial photos contained in the
Draft PD&E confirms the proposed
barrier length
Receiver location Receivers appear correctly modeled with
the exception of the RW96.1 which has a
ground elevation 30 feet different from
nearby receivers
Impacted receivers Manual counts of impacted receivers
(based on TNM results) confirms the
results in the Draft PD&E
Benefited receivers Manual counts of benefited receivers
(based on TNM results) confirms the
results in the Draft PD&E
Barrier height Additional TNM runs indicate that a 12
foot shoulder barrier may be as effective
as the proposed 14 foot barrier with the
exception ofRW100
Overall, the TNM models appear thorough and accurate with the exception of the
receiver ground elevation at RW96.1 which, by itself, did not affect the barrier design or
the number of benefited receivers.
Reasonableness Methodology
The Florida Department of Transportation (FDOT) Project Development and
Environment Manual provides the state policy for the Noise Study of the PD&E and has
recently been updated [3]. The FDOT PD&E Manual contains a list of items that are to
be considered when evaluating the reasonableness of a barrier for abatement of
residences that are found to be impacted by the project build option. The normalized
barrier cost is calculated by dividing the estimated barrier cost by the number of receivers
that benefit from the barrier. This is a critical reasonableness criteria and usually decides
whether or not a proposed barrier will be considered in the design phase of the project. A
"benefited receiver" is defined by the FDOT PD&E Manual [2][3] as:
"Benefitted receiver: A benefitted receiver is a noise sensitive receiver that will obtain a
minimum of 5 dBA of noise reduction as a result of the use of a specific noise abatement activity
regardless of whether or not they are identified as impacted. Only benefitted receivers will be
Version July 30, 2007
5
included in the calculation needed to determine that any particular noise abatement scheme has
a reasonable cost. n
FOOT PO&E Manual, 2003 Version
The Draft PD&E was submitted in April of2007 and the TNM data files were last
modified in April 2007 but the project commenced while the 2003 version of the PD&E
manual was applicable. For this reason the reasonableness criteria used in the Draft
PD&E references the 2003 version of the PD&E Manual [2].
The Turnpike Enterprise uses barrier unit costs that are dependent on the size and
location of the barrier (shoulder vs. non-shoulder). These unit costs differ from those
published by the Florida DOT ($25/sqf stated in the 2003 version of the PD&E Manual
[2]).
The barrier unit cost to be used in the PD&E, according to the FDOT policy, is stated in
section 17-4.6 of the PD&E Manual [2]
"Barrier costs should be calculated by multiplying the length of the barrier by the height to
determine the surface area of the barrier and multiplying this by the current cost per square meter
or per square foot factor for cost estimating pur~oses. Effective October 1, 2000, all new noise
studies will use a cost factor of $269.10/m ($25.00/ff). This change is based on the most
recent barrier cost data and will be adjusted as needed based on an annual review. The use of
the current cost estimate factor, $215.28/m2 ($20.00/tr), is to be continued on all noise studies
that were begun using this factor."
Table 4 contains barrier size and benefited receiver information found in the Draft PD&E
and calculations based on the unit barrier cost found in the FDOT PD&E Manual [2].
Table 4 shows that the use ofthe barrier unit cost found in the 2003 version of the PD&E
Manual results in both the "Seneca BendlTuscawilla Communities" and the "Oak Hill,
Shed Grove, Worthington" proposed barriers meeting the cost per benefited receiver
criteria of$35,000. This results in both barriers meeting the reasonableness criteria as
specified in the PD&E Manua1.[2]
Version July 30, 2007
Table 4. Cost per benefited receiver values from the Draft PD&E [1] and calculated
using values from the 2003 FDOT PD&E Manual 0.
Draft Number of
PD&E benefited
Community Location Barrier residences
size (Draft
(sqf) PD&E)
6
Draft
PD&E
barrier cost
Draft
PD&E
cost per
benefited
Barrier
cost using
PD&E
Manual
($25/ sqf)
receiver
Seneca Bend
and
Tuscawilla
Communities
$48,636
1510-
1544
55,970
45
$2,188,640
(above $1,399,250
$35k
upper
limit)
Oak Hill
Villas, Shed
Grove,
Worthington
$33,573
1520-
1581
91,320
68
$2,283,000
(below $2,283,000
$35k
upper
limit)
Future changes in the project will require a reevaluation of the PD&E Noise Study. In the
event that projected traffic volumes change, the number of lanes change or lane
alignment changes, the PD&E Noise study will have to be reevaluated and the current
PD&E manual and its guidelines will be used in that scenario. For this reason, the
following section discusses the guidelines found in the current FOOT PD&E Manual
which was released in April, 2007.
FOOT PO&E Manual, 2007 Version
Section 17-4.6.1.1 of the FDOT PD&E Manual [3] (April, 2007) states the following in
regard to the barrier cost per square foot to be used in the PD&E:
"Barrier costs should be calculated by multiplying the length of the barrier by the height to
determine the surface area of the barrier and multiplying this by the current cost per square foot
factor for cost estimating purposes. Noise studies will use a cost factor of $30.00 per square
foot."
The same section states the following in regard to maximum cost per benefited receiver
to be used in the reasonableness decision:
"Using a unit cost of $30.00 per square foot, a reasonable cost of $42,000 per
benefited receiver is looked upon as an upper limit although a higher level of expenditure can
be used if justified by other circumstances."
Cost per
benefited
receiver
using
$25/sqf
$31,094
(below
$35k
upper
limit)
$33,573
(below
$35k
upper
limit)
Version July 30, 2007
7
The Turnpike Enterprise uses barrier costs estimates that are dependent on the size and
location of the barrier (shoulder vs. non-shoulder). These cost estimates differ from those
published by the Florida DOT ($30/sqfin the 2007 version of the PD&E Manual[3]).
Table 5 contains barrier size and benefited receiver information found in the Draft PD&E
and calculations based on the unit barrier cost found in the 2007 FDOT PD&E Manual
[3].
Table 5. Cost per benefited receiver values from the Draft PD&E [1] and calculated
using values from the 2007 FDOT PD&E Manual @J.
Draft Number of Draft Barrier Cost per
PD&E benefited Draft PD&E cost using benefited
Community Location Barrier residences PD&E cost per PD&E receiver
size (Draft barrier cost benefited Manual using
(sqt) PD&E) receiver ($30/sqt) $30/sqf
Seneca Bend
and $48,636
Tuscawilla 1510- $37,313
Communities 1544 55,970 45 $2,188,640 (above $1,679,100
$42k (below $42k
upper upper limit)
limit)
Oak Hill
Villas, Shed $33,573
Grove, 1520- $40,288
Worthington 1581 91,320 68 $2,283,000 (below $2,739,600
$42k (below $42k
upper upper limit)
limit)
The 2007 FDOT PD&E Manual states an additional reasonableness criterion for a
proposed sound reduction barrier. This criteria relates the size of a barrier to benefited
receivers rather than using a dollar cost value which can be subject to variability (over
time) and subjectivity. Section 17-4.6.1.1 of the PD&E Manual [3] states:
"The relationship between unit costs and the upper limit for cost reasonableness will be
based on maintaining a constant upper limit of 1,400 square feet of noise barrier per
benefited receiver."
Table 6 contains calculations of square footage per benefited receiver based on the total
size of the proposed barriers and number of benefited receivers found in the Draft PD&E.
The table shows that the proposed "Seneca BendITuscawilla Communities" barrier meets
the 2007 criteria for barrier size per benefited receiver of 1400 square feet per benefited
receIver.
Version July 30, 2007
8
Table 6. Calculated Barrier size per benefited receiver based on Draft PD&E [1]
barrier size and benefited receiver tabulation.
Draft
PD&E
Barrier
size (sq t)
Community
Location
Number of
benefited
residences (from
Draft PD&E)
Calculated Barrier
arealbenefited
receiver
Seneca Bend
and Tuscawilla
Communities
Oak Hill
Villas, Shed
Grove,
Worthington
1510-1544
55,970
45
1244 sqf
(below upper limit)
1520-1581
91,320
68
1343 sqf
(below upper limit)
In the event that the PD&E Noise Study is reevaluated, the "Seneca BendlTuscawilla
Communities" barrier will meet the reasonableness criteria for cost per benefited receiver
and barrier size per benefited receiver as stated in the 2007 FDOT PD&E Manual [3].
Conclusions
A review of the Draft PD&E for the S.R. 417 expansion project [1] has resulted in the
following observations and conclusions.
1. The proposed barrier to abate the noise impact at the "Seneca Bend/Tuscawilla
Communities" meets the FDOT reasonableness criteria when using the barrier
unit cost specified in the 2003 FDOT PD&E Manual [2].
2. The proposed barrier to abate the noise impact at the "Seneca BendlTuscawilla
Communities" meets the 2007 FDOT guidelines for cost per benefited receiver
and square footage per benefited receiver. The most recent version of the PD&E
Manual will be followed if a review of the Noise Study is required (ie projected
future traffic changes, lane changes or lane realignment)
3. The TNM input models developed as part of the Noise Study [1] appear to be
thorough and accurate with the exception of one receiver ground elevation
(RW96.1) in the Seneca Bend Community. The ground elevation was adjusted to
a value consistent with other receivers in the vicinity and the existing and future
case models were rerun. This change resulted in an increase of impacted
receivers for Seneca Bend/Tuscawilla communities but did not affect the
benefited receivers reported in the Draft PD&E for the Seneca Bend/Tuscawilla
communities.
4. According to the Turnpike Enterprise, a ROW barrier is subject to the unit cost
found in the PD&E Manual ($25/sqf in the 2003 version) whereas a shoulder
barrier is subject to a variable unit cost that includes additional safety features.
The Draft PD&E TNM input files contain several "Seneca BendlTuscawilla"
ROW barrier designs and a review of them shows that the best case scenario
Version July 30, 2007
9
(smallest total barrier area with a sufficient number of benefited receivers) still
results in a barrier that exceeds the cost criteria.
Based on items # 1 and #2 and this particular situation where a sound barrier is found to
be reasonable for the Oak Villas/ Shed Grove/Worthingtonl communities on one side of
S.R. 417 and not for communities on the opposite side, it is my opinion that the
reasonableness decision to provide a barrier to the "Seneca BendlTuscawilla
Communities" should be reconsidered.
Version July 30, 2007
REFERENCES
1. "Draft Project Development and Environment Noise Study Report, Widening
Seminole Expressway (SR 417) from South of Aloma A venue to the Rinehart
Road Interchange", Seminole County, Florida, Financial Project ID#417545-1,
April 2007.
2. Project Development and Environment Manual, Florida Department of
Transportation, Part 2, Chapter 17, October 6, 2003.
3. Project Development and Environment Manual, Florida Department of
Transportation, Part 2, Chapter 17, April, 2007.
4. Federal Highway Administration Report Number FHWA-PD-96-009, "FHWA
Traffic Noise Model, Version 1.0 User's Guide." January 1998, Available from
McTrans Center, University of Florida, Gainesville, Florida.
10
An employee-owned company
General Consultant
Florida's Turnpike Enterprise
Florida Department of Transportation
PBS'
~
EXHIBIT B
July 18, 2007
Brian Fields, P.E.
City Engineer
City of Winter Springs
1126 East State Road 434
Winter Springs, FL 32708
Subject:
Responses to Noise Study Technical Review
Seminole Expressway Widening
Project Development & Environment (PD&E) Study
From MP 38 to MP 54
Financial Project ID Number: 417545-1
Seminole County, Florida
Dear Mr. Fields:
The Florida's Turnpike Enterprise would like to thank you for your interest in the
Seminole Expressway Widening PD&E Study. We have reviewed your submittal titled
Technical Review of Seminole Expressway Draft PD&E dated July 5, 2007. The
following provides our responses to the suggestions outlined in the Technical Review
and also documents our telephone discussion on July 16, 2007. We noted three issues
in your Technical Review. Each issue is identified below followed by our response.
1. Receiver Point RW96.1
The Technical Review correctly identifies an input error for the ground elevation at
receiver point RW96.1. The assigned height above ground (i.e., 5 feet) was
inadvertently placed in the Z(ground) column. With the Z(ground) corrected to 38 feet,
the predicted noise level increased to 65.9 dBA, which is still below the impact criteria.
As indicated in your Technical Review, this error will not affect the outcome of the noise
barrier analysis.
2. 12-foot versus 14-foot Barrier
The information provided in the Technical Review concerning the effect of lowering the
barrier from 14 feet to 12 feet is correct for receiver point RW100. However, the
Technical Review overlooks the effect the decreased barrier height would have on
receiver points that are not impacted but still benefited (i.e., provided at least a 5 dBA
reduction) with a 14 foot barrier. Residences identified as not impacted can be
incidentally benefited as discussed on page 7, paragraph 3 of the Draft PD&E Noise
Study Report.
P.O. Box 613069 · Ocoee, FL 34761
Turnpike Mile Post 263, Building 5315 · Ocoee, Florida 34761 · Telephone: 407.532.3999
Mr. Fields
July 18, 2007
Page 2
According to the noise model results, RW100 and an additional 7 non-impacted
residences would not be benefited if the barrier height were reduced to 12 feet. With a
total of eight less benefited residences, the cost of the 12-foot high barrier is $49,084
per benefited residence which is greater than the.$48,636 per benefited residence for a
14-foot high barrier. Therefore, the Draft PD&E Noise Study Report correctly identifies
the 14-foot high option as the most cost reasonable.
3. $25/W Unit Cost for Noise Barriers
The Technical Review correctly identifies the unit cost of a noise barrier ($25/tf) as
documented in the October 2003 version of the PD&E Manual. However, the PD&E
Manual (Section 17-4.6.1, Item 16) also states "that the cost estimate does not include
costs associated with ROW needs or other special design considerations required by
unique site conditions." The PD&E Manual also states that costs can vary considerably
based on ". . . proximity to roadways. . ." A noise barrier located along the shoulder of a
highway (i.e., within the clear recovery zone) has special design characteristics that are
required to meet crash safety requirements.
Standard Index 5211 of the FOOT Design Standards refers to a shoulder barrier as a
Traffic Railing/Sound Barrier. Notes within the Standard Index identify the special
design characteristics that result in additional costs over the $25/tf. These additional
costs are generally associated with supplemental reinforcing steel and special footing
designs that meet crash safety requirements. Noise barriers located along the right-of-
way are outside the clear recovery zone and therefore, do not incur the additional costs
needed to meet safety standards.
Hopefully, this provides you a better understanding of the procedures and criteria used
by the Florida's Turnpike Enterprise when evaluating noise barriers. As documented in
the Draft PD&E Noise Study Report and discussed during our telephone conversation,
the PD&E phase noise study indicates that a noise barrier is not a cost reasonable
abatement measure for the Seneca Bendrruscawilla communities. However, we have
committed to reanalyzing a noise barrier for these communities during the design phase
of this project. If you should have any additional questions concerning the traffic
noise/noise barrier evaluation procedures, please contact me at (407) 264-3803.
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HP/cc