CATEGORICAL EXCLUSION LOOP 1604 at SH 151 SAN ANTONIO

179 Pages·2011·17.27 MB·English

CATEGORICAL EXCLUSION

LOOP 1604
at SH 151
SAN ANTONIO, BEXAR COUNTY, TEXAS
CSJ: 2452-01-043

DECEMBER 2011

ALAMO REGIONAL MOBILITY AUTHORITY

TEXAS DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION
TABLE OF CONTENTS

I.  SURROUNDING AREA ..................................................................................................... 1 
II.  DESCRIPTION OF THE EXISTING FACILITY ........................................................... 1 
III.  NEED AND PURPOSE FOR THE PROPOSED PROJECT .......................................... 2 
IV.  DESCRIPTION OF THE PROPOSED ACTION ............................................................ 3 
V.  POTENTIAL ENVIRONMENTAL EFFECTS................................................................ 7 
A.  AIR ..................................................................................................................................... 7 
B.  NOISE ................................................................................................................................ 8 
C.  WATER RESOURCES .................................................................................................. 11 
D.  VEGETATION ............................................................................................................... 13 
E.  FISH AND WILDLIFE COORDINATION ACT ....................................................... 15 
F.  THREATENED & ENDANGERED SPECIES ........................................................... 16 
G.  MIGRATORY BIRD TREATY ACT ........................................................................... 31 
H.  FARMLAND PROTECTION POLICY ACT ............................................................. 31 
I.  CULTURAL RESOURCES ........................................................................................... 31 
a.  Historic Structures .......................................................................................................... 31 
b.  Archeological Resources ............................................................................................ 32 
J.  SECTION 4(f).................................................................................................................. 32 
K.  HAZARDOUS MATERIALS ........................................................................................ 32 
L.  CONSTRUCTION IMPACTS ...................................................................................... 33 
M.  COMMUNITY IMPACTS ............................................................................................. 34 
N.  ENVIRONMENTAL JUSTICE .................................................................................... 34 
O.  LIMITED ENGLISH PROFICIENCY ........................................................................ 36 
P.  PUBLIC INVOLVMENT .............................................................................................. 37 
Q.  PERMITS/COMMITMENTS ....................................................................................... 41 
R.  INDIRECT AND CUMULATIVE IMPACTS ............................................................. 38 
VI.  CATEGORAL EXCLUSION DETERMINATION ....................................................... 41 

EXHIBITS
Exhibit 1 Project Location
Exhibit 2 Existing Typical Section
Exhibit 3 Proposed Typical Sections
Exhibit 4 Project Layout
Exhibit 5 Noise Receptors
Exhibit 6 USGS/FEMA
Exhibit 7 Water Crossings Location Map
Exhibit 8 Vegetation Types of Texas
Exhibit 9 Vegetation Impact Area
Exhibit 10 Karst Zones
Exhibit 11 Census Tracts

APPENDICES
Appendix A Project Photos
Appendix B MTP 2035 and TIP 2011-2014 – Loop 1604 at SH 151 Project Listing
Appendix C Correspondence
Appendix D Technical Reports
ENVIRONMENTAL DOCUMENT
Loop 1604
at SH 151
San Antonio, Bexar County, Texas
CSJ: 2452-01-043
December 2011

I. SURROUNDING AREA
A. SETTING
The proposed project is located on Loop 1604 at State Highway (SH) 151 in San Antonio, Bexar
County, Texas. The topography is generally rolling terrain with elevation generally ranging from 920 to
970 feet above sea level within the project limits. Two tributaries to Culebra Creek exists within the
project study area. The proposed project is located within the San Antonio River Basin. The project is
located in a developing area of San Antonio. Recent development includes the Valero gas station,
Courtyard Marriott, and Fairfield Inn and Suites Marriot all located at Wiseman Boulevard (Blvd.) and
SH 151. Also, Christus Santa Rosa Hospital and medical offices recently opened immediately east of
the project area on SH 151 at Westover Hills. According to the Vegetation Types of Texas (TPWD,
1984), the proposed project is located within vegetation type Mesquite-Live Oak-Bluewood Parks.
Study area vegetation is generally consistent with this vegetation type. Exhibit 1 shows the project
location and limits. Photographs of the project area are in Appendix A.
B. SURROUNDING LAND USE
The land use adjacent to the existing roadway is urban developed and undeveloped with a variety of
adjacent commercial developments. Within the last two years, residential and commercial development
has been explosive at the Loop 1604 intersection with Culebra Road, northwest of the project area,
which includes over 900,000 square feet of commercial development on 114 acres. Northwest Vista
College and SeaWorld San Antonio are located southeast of the project area. No parks or other schools
are located directly adjacent to Loop 1604 at SH 151.

II. DESCRIPTION OF THE EXISTING FACILITY
The existing Loop 1604 facility within the project area is predominantly a 4-lane divided non access-
controlled roadway with grassy median and open ditches. The existing right-of-way (ROW) is 350 feet
(usual) widening to over 500 feet at SH 151. In both directions of Loop 1604, an existing pavement
width of 38 feet is configured with two 12-ft lanes, a 4-ft inside shoulder, and 10-ft outside shoulder.
The existing grassy median has a width of 64 feet. The current posted speed limit is 55 miles per hour
(mph). (See Exhibit 2A: Existing Typical Sections). The existing 2011 average daily traffic (ADT) is
approximately 29,160 vehicles per day (VPD) in the northbound (NB) direction and 19,790 VPD in the
southbound (SB) direction. The length of the proposed improvements along Loop 1604 is
approximately 0.4 miles.

Frontage roads in both directions of Loop 1604 exist for a length of about 1.5 miles to the north of the
project area to manage access through existing interchanges with FM 471 (Culebra Road) and with SH
151. At SH 151, the northbound frontage road of Loop 1604 forms ramps connecting with SH 151 to
the east. The southbound frontage road of Loop 1604 has an existing non-signalized T-intersection with
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Alamo Ranch Parkway to the west. The Loop 1604 main lanes in both directions connect with SH 151
eastbound via an existing at-grade signalized intersection.

The existing facility on SH 151 approaches the project area from the southeast as a 4-lane divided
access-controlled roadway with continuous frontage roads, grassy median, and open ditches. The
existing right-of-way (ROW) is 400 feet. In both directions of SH 151, an existing main lane pavement
width of 38 feet is configured with two 12-ft lanes, a 4-ft inside shoulder, and 10-ft outside shoulder.
The existing grassy median has a width of 40 feet. (See Exhibit 2B: Existing Typical Sections). The
existing SH 151 main lanes currently end approximately 0.75 miles east of Loop 1604 by merging into
the frontage roads. The westbound frontage road ties into both the northbound Loop 1604 main lanes
and the northbound frontage road. SH 151 drivers destined for southbound Loop 1604 must travel
northbound on Loop 1604 and use the turnaround at FM 471 (Culebra Road). SH 151 does not continue
beyond Loop 1604 to the northwest. The current posted speed limit is 55 miles per hour (mph). The
existing 2011 average daily traffic (ADT) is approximately 16,060 VPD. The length of the proposed
project is approximately 1.2 miles along SH 151.

III. NEED AND PURPOSE FOR THE PROPOSED PROJECT
The needs or problems to be addressed for the proposed project are decreased mobility and operational
efficiency. Over the past 10 years, development has increased substantially outside of Loop 1604,
particularly in the vicinity of its intersection with Culebra Road (FM 471) near SH 151. In accordance
with the City of San Antonio’s Major Thoroughfare Plan, a new arterial, Alamo Ranch Parkway,
extending radially from, but not connecting to SH 151 to the northwest was built in order to provide
needed circulation and connectivity. Alamo Ranch Parkway provides a much needed radial link from
the mega multi-use developments in the northwest area of the city to destinations along and inside Loop
1604. However, because Alamo Ranch Parkway does not directly connect to SH 151 at Loop 1604,
congestion levels and safety issues at adjacent intersections with Loop 1604 are becoming problematic.
Crash data for SH 151 between Wiseman Blvd. and Loop 1604 was reviewed for the years 2007 through
2010. During these years, 270 traffic crashes were documented. Of these, 133 were Loop 1604/SH 151
intersection-related crashes. Two crashes in 2010 resulted in fatalities at this intersection.

Congestion levels have been impacted by population growth within the project area. The population has
grown 38% and 59%, respectively between the two project-area zip codes (78253 and 78251) according
to Census data between 1990 and 2000. The latent travel demand due to the lack of an Alamo Ranch
Parkway/SH 151 connection has substantially impacted operations along FM 471 as well as the
intersections of Loop 1604/FM 471 and Loop 1604/Wiseman Boulevard. The purpose of the project is
to enhance mobility and operational efficiency in the near-term by constructing an underpass linking SH
151 and Alamo Ranch Parkway. This type of improvement or reconfiguring of the intersection at Loop
1604/SH 151 and Alamo Ranch Parkway does not add capacity to the system but does significantly
improve the safety and operations within the roadway system. Long-term solutions to address capacity
needs along the Loop 1604 corridor are being studied in a separate environmental document.

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IV. DESCRIPTION OF THE PROPOSED ACTION
A. ROADWAY CONSTRUCTION
The Texas Department of Transportation (TxDOT), in cooperation with the Alamo Regional Mobility
Authority (RMA), and Bexar County, is proposing to construct an underpass linking Alamo Ranch
Parkway with SH 151 beneath Loop 1604. The Alamo RMA is a local transportation authority created
by the Texas Transportation Commission and the Bexar County Commissioners Court in December
2003 that can build, operate, and maintain transportation facilities under all of the existing federal and
state regulations and interagency agreements in place through TxDOT. The proposed project limits are
on Loop 1604 at SH 151. The logical termini for this action are determined by the proposed
reconfiguration of the Loop 1604/SH 151 and Alamo Ranch Parkway intersection, which includes the
connection of SH 151 main lanes to Alamo Ranch Parkway and the grade separation of the Loop 1604
main lanes. As such, construction limits along SH 151 begin at the existing terminus of the SH 151
main lanes and end at the intersection with Alamo Ranch Parkway. Construction limits along Loop
1604 generally include the proposed main lane bridges over SH 151 and their approaches.
Correspondence between TxDOT and FHWA (Appendix C) describe the project’s independent utility
and independent need and purpose.

The proposed improvements would include the reconfiguration of the Loop 1604/SH 151 and Alamo
Ranch Parkway intersection in order to connect SH 151 inside Loop 1604 to Alamo Ranch Parkway
outside Loop 1604. Two bridges would be constructed for the northbound and southbound Loop 1604
main lanes, matching the existing vertical alignment of Loop 1604, to provide a grade separated
overpass of the proposed SH 151 main lanes. The approaches to the new bridges would be overlaid with
asphalt and new pavement markings would be applied. Additionally, the southbound main lanes of
Loop 1604 would be sawcut and widened to a width of 4 ft to 12 ft for a distance of approximately 600
ft in order to align with the proposed bridges.

The eastbound and westbound main lanes of SH 151 would be extended approximately 0.75 miles to the
west, pass beneath Loop 1604 main lanes, and connect with Alamo Ranch Parkway. The existing non-
signalized T-intersection of the Loop 1604 southbound frontage road and Alamo Ranch Parkway would
be reconstructed into an at-grade signalized intersection just west of the underpass where the SH 151
main lanes would terminate at their intersection with the southbound Loop 1604 frontage road and
Alamo Ranch Parkway.

Widening SH 151 is proposed for a distance of approximately 1500 feet to add an auxiliary lane for
westbound traffic passing under Wiseman Blvd. This widening would maintain the existing two-lane
exit ramp to Loop 1604. The maximum width of widening for this section of SH 151 would be 11 ft.
The project would also include overlaying the existing asphalt and applying new pavement markings.

Turning movements between southbound Loop 1604 frontage and Alamo Ranch Parkway/SH 151
would be facilitated through the at-grade signalized intersection. Traffic traveling on northbound Loop
1604 has the same access to Alamo Ranch Parkway as they do presently, and the new at-grade
intersection east of Loop 1604 will not facilitate this turning movement. Westbound SH 151 drivers
destined for southbound Loop 1604 and Alamo Ranch Parkway would be able to use the reconfigured
intersection in lieu of the FM 471 (Culebra Road) turnaround. Southbound 1604 traffic destined for
eastbound SH 151 would exit the Loop 1604 main lanes and turn left at the signalized intersection of the
SH 151 main lanes and the southbound frontage road. The northbound Loop 1604 to westbound Alamo
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Ranch Parkway movement would remain as it exists today. To access westbound Alamo Ranch
Parkway, traffic traveling north on Loop 1604 would utilize the turnaround at FM 471 (Culebra Road).
Eastbound Alamo Ranch Parkway traffic also maintains access to northbound Loop 1604 as it does
presently: (1) turn northbound on Westwood Loop, continue north to Culebra Road, and access
northbound Loop 1604 through the Culebra Road/Loop 1604 intersection (the most common route
presently utilized) or, (2) travel south at the Loop 1604 southbound frontage road to enter the ramp onto
Loop 1604 southbound and utilize the turnaround at Wiseman Road. Westbound SH 151 traffic
destined to northbound Loop 1604 movements as well as northbound Loop 1604 destined to eastbound
SH 151 movement would remain as they exist today. Loop 1604 main lane traffic traveling northbound
and southbound would no longer have a signalized intersection at SH 151. The existing pavement
(shown as “Pavement Removal” in Exhibit 4C) connecting Loop 1604 southbound frontage road to
eastbound SH 151 would be removed.

Drainage improvements would include constructing a box culvert under SH 151 approximately 1600
feet east of Loop 1604. Currently, two separate box culverts exist on the eastbound and westbound
frontage roads of SH 151 with an earthen channel between the two culverts. This project would connect
these two box culverts and eliminate the earthen channel. In addition, approximately 1900 feet of storm
sewer system would be constructed on SH 151. The storm sewer system would begin approximately
1200 feet east of Loop 1604, run along both sides of the proposed SH 151 main lanes, and then turn to
the north to tie into the existing box culverts that cross the Loop 1604 southbound frontage road. There
are also two additional culverts proposed to drain runoff from the east side of Loop 1604, crossing under
Loop 1604 main lanes, to tie into existing box culverts on the west side of Loop 1604 main lanes.

The overall length of the proposed improvements along SH 151 would be 6,500 feet, or 1.2 miles. See
Exhibit 3: Proposed Typical Sections and Exhibit 4: Project Layout. The projected 2031 ADT for
SH 151 is 27,780 VPD. The projected 2031 ADT for Loop 1604 is 30,950 VPD NB and 21,005 VPD
SB. No change to the existing speed limit (55 mph) is proposed.
B. RIGHT-OF-WAY
The proposed improvements would not require any new ROW acquisition or easements. No
displacements of residences or businesses would result. The proposed project would preserve business
access and no driveway changes are anticipated.
C. BICYCLES AND PEDESTRIANS
Per 23USC 109(m) “Protection of Nonmotorized Transportation Traffic”, The Secretary shall not
approve any project or take any regulatory action under this title that will result in the severance of an
existing major route or have significant adverse impact on the safety for nonmotorized transportation
traffic and light motorcycles, unless such project or regulatory action provides for a reasonable
alternate route or such a route exists. Existing pedestrian facilities in the vicinity of proposed project
include cross walks at the intersection of SH 151 and Wiseman Blvd., and a discontinuous sidewalk
along the southbound frontage road along Loop 1604 from Culebra Road to Alamo Ranch Parkway.
There are no proposed improvements to pedestrian facilities. Neither the pedestrian crosswalk across
SH 151 at Wiseman Blvd. nor the discontinuous sidewalk would be modified by the proposed
improvements.

Provisions for bicycles were considered during development of the proposed project. In the 2009
Bicycle Conditions map for the Bexar County MPO Bicycle Master Plan, Alamo Ranch Parkway is
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considered “fair” (a street that can accommodate experienced and casual bicyclists, and/or may need
altering to accommodate youth bicyclists). The SH 151 frontage (access roads only, roads are
considered “Good” (streets that can reasonably accommodate for all types of bicyclists, except for
children under 10). The SH 151 mainlanes (like Loop 1604, IH-410, IH-35, IH-10 and other major
highways and expressways) do not contain a designation in this map.

From the local perspective, the San Antonio-Bexar County Metropolitan Planning Organization (MPO)
is continuously seeking input from standing committees known as the Bicycle Mobility Advisory
Committee and the Pedestrian Mobility Advisory Committee. The San Antonio-Bexar County Bicycle
Master Plan was approved by the San Antonio City Council on April 21, 2005 and Bexar County
Commissioners Court by resolution on July 12, 2005. Also, the San Antonio-Bexar County MPO
Metropolitan Transportation Plan (MTP) 2035 includes planning for bicycle and pedestrian
improvements. The Bicycle Master Plan was designed to serve as the primary document considered in
planning for bicycle facilities in the region while the MTP is the San Antonio-Bexar County’s
financially constrained plan for regional transportation improvements. Neither the Bicycle Master Plan
nor the MTP 2035 (either funded or unfunded bicycle or pedestrian improvements) are identified within
the Loop 1604 or SH 151 proposed project corridor.

An appropriate connection across Loop 1604, connecting SH 151 with Alamo Ranch Parkway, for use
by bicyclists and pedestrians wanting to travel across the Loop 1604 corridor is provided on FM 471
(Culebra Road) which is approximately 0.20 mi. north of the Loop 1604/SH 151 intersection. Currently,
bicyclists using the SH 151 frontage roads may access existing bicycle accommodations on FM 471
(Culebra Road) to reach Alamo Ranch Pkwy on the west side of Loop 1604 using the existing SH 151
frontage road that travels along northbound Loop 1604 to the FM 471 (Culebra Road) intersection.
From Culebra Rd. bicyclists can travel south along the Loop 1604 frontage road shoulder to Alamo
Ranch Pkwy and continue on this recommended corridor while staying on routes considered “good” or
“fair” by the Bexar County MPO in its 2009 Bicycle Conditions Map.

Similarly, bicyclists would access SH 151 from Loop 1604 at FM 471 (Culebra Road) as well.
Following the City of San Antonio’s San Antonio Bike Plan 2011, the recommended bicycle route
would utilize Rogers Road. The bike route from Loop 1604 at FM 471 (Culebra Road) would follow
FM 471 (Culebra Road) to Rogers Road, and from Rogers Road to Wiseman Boulevard (Blvd).
Wiseman Blvd. would have bike access to SH 151 and Loop 1604. This recommendation would not
preclude experienced cyclists from following the Loop 1604 shoulder southbound from FM 471
(Culebra Road) to Wiseman Blvd.

The existing shoulder condition on SH 151 frontage roads within the proposed project limits (Wiseman
Blvd. to Loop 1604) ranges from 0 to 10 feet. The proposed project would not modify the existing
shoulder condition; however, the construction of main lanes along SH 151 would improve conditions for
bicyclists on the frontage roads by separating high speed traffic from local and bicycle access along the
frontage road.

The Bexar County Bicycle Mobility Plan (BMP) Long-Range Plan (Transvision 2015), 1995, has the
goal of seeing all transportation facilities in the San Antonio-Bexar County area accommodating, at a
minimum, experienced cyclists. These cyclists are able to utilize existing shoulders and signal lights
alongside vehicular traffic. These accommodations will exist in the proposed project; however, the
BMP Long-Range Plan also calls for key bicycle corridors to accommodate all types of cyclists (skilled,
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basic, and children). Even though the SH 151 corridor is considered at least a “Recommended Bike
Corridor” by the Bicycle Master Plan Corridor Map, the mainlanes of SH 151 do not meet this goal of
accommodating all types of cyclists. The proposed project would add an expressway grade separation
with the purpose of linking SH 151 with Alamo Ranch Pkwy across Loop 1604. As such, frontage roads
are not included in the plans. This project maintains the ability for all bicyclists to use the existing
frontage roads, as recommended by the BMP Long-Range Plan, of SH 151 to Culebra Road and then
east along the corridor. Safe passages for bicycle and pedestrian facilities are currently under
consideration under a separate environmental study for the Loop 1604 corridor. (See Appendix C:
Correspondence for coordination with the City of San Antonio).
D. ALTERNATIVES
Three alternatives were reviewed for satisfying the need and purpose of the proposed improvements to
Loop 1604 and SH 151. These include the Build Alternative (SH 151 Underpass), SH 151 Overpass
Alternative, and the No Build Alternative. The No Build Alternative is required for review as a basis of
comparison for all other alternatives.

No Build
The No Build Alternative would leave the Loop 1604 and SH 151 corridor in its current condition. The
No Build alternative would include all other planned improvements in the MPO long range
transportation plan. Under the No Build Alternative, the safety and mobility benefits of the proposed
project would not be realized. As traffic volumes in the study area continue to increase, safety and
mobility would decline. For these reasons, it was determined that the No Build Alternative would not
meet the Need and Purpose of the proposed project. Further, it is not consistent with the MPO
Transportation Improvement Program.

SH 151 Overpass Alternative
This alternative would allow SH 151 to overpass Loop 1604. This alternative was eliminated from
further consideration after early initial design analysis. In consideration of a potential future direct
connector interchange at this location, stacking SH 151 over Loop 1604 would require an increase in the
height of the direct connectors by one level (approximately 25 feet). This would increase the cost of the
future interchange as well as steepening the grade of the connectors.

Also, the topography of the project area would require that SH 151/Alamo Ranch Parkway be
significantly higher than the adjacent property around the roadway in the area just west of Loop 1604.
This option would require an approximate 50-foot retaining wall precluding the desired access to and
from Alamo Ranch Parkway and the adjacent properties/developments in the area. Further, it would
require a much larger right of way footprint for slopes which would be undesirable due to cost and
potential environmental impacts.

Build Alternative (SH 151 Underpass)
The Build Alternative would implement the interchange improvements as discussed previously. The
Build Alternative would best fulfill the Need and Purpose of the proposed project.
E. UTILITY CONSTRUCTION
Utility adjustments are anticipated to implement the proposed project. Specifically, adjustments would
be needed for CPS Energy gas lines. Coordination with project study area utility providers is ongoing
and would be completed prior to project construction.
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F. PROJECT FUNDING
The San Antonio-Bexar County Metropolitan Planning Organization (MPO) approved the funding of the
Loop 1604 at SH 151 proposed project with funding from Strategic Priority “Category 12”. The Texas
Transportation Commission has determined that money from this Category 12 will be used on an “as
needed” basis, for projects with specific importance to the state. These projects will generally promote
economic opportunity, increase efficiency on military deployment routes or to retain military assets in
response to the federal military base realignment and closure report, or maintain the ability to respond to
both man-made and natural emergencies. In addition, the Commission is also committed to utilize the
Category 12 funds to help communities utilize the new financing tools, like pass-through financing
agreements, in order to help local communities address their transportation needs.

The funding for this project is 80 percent federal and 20 percent state. The proposed action is consistent
with the San Antonio, Bexar financially constrained 2035 MTP and 2011-2014 Transportation
Improvement Program (TIP). The total project cost is $21,774,600 as of March 1, 2010. The proposed
project letting date is January 2012 with an estimated time of completion of November 2013. Copies of
the applicable pages of the TIP and the MTP with project listings are included in Appendix B.

V. POTENTIAL ENVIRONMENTAL EFFECTS
A. AIR

a. Transportation Plan Consistency
The proposed action is consistent with the San Antonio, Bexar financially constrained 2035 MTP and
2011-2014 Transportation Improvement Program (TIP) (Appendix B). The project is located in Bexar
County, which is in attainment of all National Ambient Air Quality Standards (NAAQS); therefore, the
transportation conformity rules do not apply. The proposed project letting date is January 2012.

b. Carbon Monoxide (CO) Traffic Air Quality Analysis (TAQA)
Generally, operational improvements are considered exempt from a TAQA because they are intended to
enhance traffic safety and improve traffic flow. The proposed action would not add capacity to an
existing facility. Current and future emissions should continue to follow existing trends not being
affected by this project. Due to the nature of this project, further carbon monoxide analysis was not
required.

c. Mobile Source Air Toxics (MSAT’s)
The purpose of this project is to improve operational efficiency. This project would not result in any
meaningful changes in traffic volumes, vehicle mix, location of existing roadways, or any other factor
that would cause a substantial increase in emissions impacts relative to the existing conditions. As such,
TxDOT and FHWA have determined that this project would generate minimal air quality impacts for
Clean Air Act criteria pollutants and has not been linked with any special Mobile Source Air Toxics
(MSAT) concerns. Consequently, this project is exempt from analysis for MSATs.

Moreover, EPA regulations for vehicle engines and fuels will cause overall MSATs to decline
significantly over the next 20 years. Even after accounting for a projected 64% increase in VMT,
FHWA predicts MSATs will decline in the range of 57 to 87% from a baseline year of 2000 to 2020
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based on the current vehicle and fuel regulations in effect. These reductions will reduce the background
level of MSATs, as well as the possibility of even minor MSAT emission increases from this project.

d. Construction Emissions
During the construction phase of this project, temporary increases in air pollutant emissions may occur
from construction activities, equipment, and related vehicles. The primary construction-related
emissions are particulate matter (fugitive dust) from site preparation and construction and non-road
mobile source air toxics (MSAT) from construction equipment and vehicles. The primary MSAT
emission related to construction is diesel particulate matter from diesel powered construction equipment
and vehicles.

These emissions are temporary in nature (only occurring during actual construction); it is not possible to
reasonably estimate impacts from these emissions due to limitations of the existing models. However,
the potential impacts of particulate matter emissions will be minimized by using fugitive dust control
measures such as covering or treating disturbed areas with dust suppression techniques, sprinkling,
covering loaded trucks, and other dust abatement controls, as appropriate. The MSAT emissions will be
minimized by measures to encourage use of EPA required cleaner diesel fuels, limits on idling,
increasing use of cleaner burning diesel engines, and other emission limitation techniques, as
appropriate.

However, considering the temporary and transient nature of construction-related emissions, as well as
the mitigation actions to be utilized, it is not anticipated that emissions from construction of this project
will have any significant impact on air quality in the area.

B. NOISE

Existing Environment
This analysis conforms to FHWA Regulation 23 CFR 772, "Procedures for Abatement of Highway
Traffic Noise and Construction Noise," and TxDOT's 2011 Guidelines for Analysis and Abatement of
Highway Traffic Noise (April 2011).

Sound from highway traffic is generated primarily from a vehicle's tires, engine and exhaust. It is
commonly measured in decibels and is expressed as "dB."

Sound occurs over a wide range of frequencies. However, not all frequencies are detectable by the
human ear; therefore, an adjustment is made to the high and low frequencies to approximate the way an
average person hears traffic sounds. This adjustment is called A-weighting and is expressed as "dBA."

Also, because traffic sound levels are never constant due to the changing number, type and speed of
vehicles, a single value is used to represent the average or equivalent sound level and is expressed as
"Leq."
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