Noise Study Report

South and East Beltways Study

Lincoln, Nebraska

Prepared for

Federal Highway Administration

Nebraska Department of Roads

Lancaster County

City of Lincoln

October 2000

(Revised 2/01)

NOISE STUDY REPORT

for

South and East Beltways Study

Lincoln, Nebraska

Page

1.0 INTRODUCTION C.4

2.0 PROJECT DESCRIPTION C.4

3.0 MEASUREMENT OF SOUND C.5

4.0 TRAFFIC NOISE STANDARDS C.6

5.0 PROJECT AREA ACTIVITY CATEGORY C.6

6.0 EXISTING 1999 NOISE LEVELS C.7

7.0 PREDICTED NOISE LEVELS C.7

7.1 PREDICTION METHODOLOGY C.7

7.2 TRAFFIC PARAMETERS C.7

7.3 PREDICTED NOISE LEVELS C.8

7.4 PREDICTED NOISE CONTOUR C. 32

8.0 NOISE ABATEMENT C.32

8.1 NOISE MITIGATION MEASURES C.32

8.1.1 SHIFTING the ROADWAY ALIGNMENT HORIZONTALLY C.32

8.1.2 CONSTRUCTING NOISE BARRIERS C.32

8.2 NOISE ABATEMENT ANALYSIS for IMPACTED RECEPTORS ALONG the SM-4 C.34

8.3 NOISE ABATEMENT ANALYSIS for IMPACTED RECEPTORS ALONG the EC-1 C.35

8.4 NOISE ABATEMENT ANALYSIS for IMPACTED RECEPTORS ALONG the EM-1 C 38

8.5 NOISE ABATEMENT ANALYSIS for IMPACTED RECEPTORS ALONG the EF-1 C.39

9.0 CONSTRUCTION NOISE C.42

10.0 SUMMARY C.43

11.0 REFERENCES C.44

Appendix C-A 2030 Average Daily Traffic Volume C.45

Table C.1 Common Noise Levels C.5

Table C.2 Noise Abatement Criteria C.6

Table C.3 Vehicle Mix Percentage C.8

Table C.4 EC-1 Alternative: Predicted Noise Levels on 27^th Street C.15

Table C.5 EC-1 Alternative: Predicted Noise Levels on Van Dorn Street C.16

Table C.6 EC-1 Alternative: Predicted Noise Levels on Old Cheney Road C.16

Table C.7 EM-1 Alternative: Predicted Noise Levels on Old Cheney Road C.17

Table C.8 EM-1 Alternative: Predicted Noise Levels on 70th Street C.18

Table C.9 EF-1 Alternative: Predicted Noise Levels on Old Cheney Road C.19

Table C.10 EF-1 Alternative: Predicted Noise Levels on 70^th Street

(between Yankee Hill and Saltillo Road) C.20

Table C.11 EF-1 Alternative: Predicted Noise Levels on 70^th Street

(between Old Cheney and N-2) C.21

Table C.12 SM-4/EC-1 Alternative Predicted Beltway Noise Levels C.22

Table C.13 SM-4/EM-1 Alternative Predicted Beltway Noise Levels C.23

Table C.14 SM-4/EF-1 Alternative Predicted Beltway Noise Levels C.24

Table C.15 EC-1 Alternative Predicted Beltway Noise Levels C.25

Table C.16 EM-1 Alternative Predicted Beltway Noise Levels C.28

Table C.17 EF-1 Alternative Predicted Beltway Noise Levels C.30

Table C.18 Noise Abatement Feasibility Review: SM-4 Alternative C.34

Table C.19 Noise Abatement Feasibility Review: SM-4 Alternative C.35

Table C.20 Noise Abatement Feasibility Review: SM-4 Alternative C.38

Table C.21 Noise Abatement Feasibility Review: SM-4 Alternative C.39

Figure C.1 Noise Receptors along 27^th Street (Table C.4)

from Pine Lake Road to Yankee Hill Road C.9

Figure C.2 Noise Receptors along Van Dorn Street (Table C.5)

from 84^th Street to 98^th Street C.10

Figure C.3 Noise Receptors along Old Cheney Road (Tables C.6, C.7 and C.9)

from 84^th Street to 98^th Street C.11

Figure C.4 Noise Receptors along 70^th Street (Tables C.8 and C.10)

from Yankee Hill Road to Rokeby Road C.12

Figure C.5 Noise Receptors along 70^th Street (Tables C.8 and C10)

from Rokeby Road to Saltillo Road C.13

Figure C.6 Noise Receptors along 70^th Street (Tables C.11)

from Old Cheney Road to N-2 C.14

11Feb01

NOISE STUDY REPORT

for

South and East Beltways Study

Lincoln, Nebraska

1.0 INTRODUCTION

This report provides a discussion of the potential traffic related noise impacts associated with the South and East Beltways Project. This noise analysis has been conducted in accordance Noise" and with "Noise with 23 CFR Part 772, "Procedures for Abatement of Highway Traffic Noise and Construction Analysis and Abatement Policy, May 1998" of the Nebraska Department of Roads. Noise levels within the study area are predicted using the Federal Highway Administration, Traffic Noise Model (TNM, Version 1b). Using the model results, predicted noise levels are compared to existing noise levels and the Federal Noise Abatement Criteria (NAC) to determine if there are any project-related noise impacts. Where impacts are predicted to occur, appropriate noise mitigation measures are evaluated, including noise barriers. Mitigation is not considered for the No Build alternative.

2.0 PROJECT DESCRIPTION

The purpose of the South and East Beltways Study has been to conduct a feasibility study and alternatives evaluation for preferred beltway alignments on the south and east fringes of the City of Lincoln to complete a circumferential transportation system. The south beltway alternative would connect US 77 with N-2, while the east beltway alternative would connect N-2 with I-80.

The study area for the south beltway is bounded on the north by Yankee Hill Road, on the south by the half-section line 0.8 km (0.5mi) south of Bennett Road, on the east by the half-section line 0.8 km (0.5 mi) east of 148^th Street, and on the west by US 77. The study area for the east beltway is bounded on the west by 98^th Street, on the east by the half-section line 0.8 km (0.5 mi) east of 148^th Street, on the north by I-80, and on the south by N-2.

The Nebraska Department of Roads Standard Section for a Rural Expressway was used for all beltway alignments. A rural expressway typical section has the following features:

• Approximately 76.2 to 91 m (250 to 300 ft) right-of-way; right-of-way needs vary with topography
• Two 3.7 m (12 ft) driving lanes in each direction
• 2.4 m (8 ft) paved outside shoulders
• 0.9 m (3 ft) paved inside shoulders
• 12 m (40 ft) unpaved depressed median (includes inside shoulders)

Construction of the east beltway alternatives will increase traffic volume on several existing roadways that cross or parallel the beltway alignments (Interim Report No. 3 (WSA, revised 1999)) and which are not necessarily in the beltway study area. The roadway segments listed below were predicted to have an increase of 50 percent or greater traffic volume dependant upon the beltway alternative selected. Therefore, the following roadway segments have been included in the noise study.

EC-1 Alternative:

• 27^th Street between Pine Lake and Yankee Hill
• Van Dorn between 84^th and 98^th Streets
• Old Cheney between 84^th and 98^th Streets

EM-1 Alternative:

• Old Cheney between 84^th and 98^th Streets
• 70^th Street between Yankee Hill and Saltillo Road

EF-1 Alternative:

• Old Cheney between 84^th and 98^th Streets
• 70^th Street between Yankee Hill and Saltillo Road
• 70^th Street between Old Cheney and N-2

3.0 MEASUREMENT OF SOUND

The Federal Highway Administration (FHWA) has specified that noise be predicted and evaluated in decibels weighted with the A-level frequency response; this unit of measure is referred to as dBA. Measurements in dBA incorporate the human ear's reduced sensitivity to both low frequency and very high frequency noises, thereby correlating well with our subjective impression of loudness. Table C.1 displays noise levels (in dBA) common to our everyday activities.

COMMON NOISE LEVELS

4.0 TRAFFIC NOISE STANDARDS

The Federal Highway Administration has developed noise abatement criteria based on the A-weighted, equivalent level noise descriptor (Leq(h)). The Leq(h) is the equivalent steady state sound level reported over a period of one hour which contains the same acoustic energy as the time-varying traffic sound level during that same hour. Table C.2 contains the upper limits of the Leq(h) desirable noise levels that are part of the Noise Abatement Criteria (NAC) established by the FHWA. Any noise levels that approach or exceed these criteria would not be desirable and would be referred to as a noise impact.

In accordance with the Nebraska Department of Roads policy, a noise impact occurs and abatement measures will be considered for receptors if:

• The predicted future year (year 2030) noise levels approach or exceed NAC criteria of 67 Leq(h) dBA for Activity Category B or 72 Leq(h) dBA for Activity Category C. Approach is defined by the NDOR as 1 dBA less than the noise abatement criteria or;
• The predicted future year (year 2030) noise level exceeds the existing noise level by 15 dBA or more.

The noise impacts predicted to occur within the project area are discussed later in this report.

5.0 PROJECT AREA ACTIVITY CATEGORY

The majority of the project lies within rural areas and the land use is classified as Activity Category "B" or "D" as described in Table C.2 above. Activity "C" land use is located near the US 77 and SM-4 interchange.

6.0 EXISTING 1999 NOISE LEVELS

Existing noise levels for the receptors adjacent to the beltway alternatives were determined by direct field measurements using a Quest 2800 sound level meter. The measurements were taken along unimproved county roadways near existing residences (generally 30 to 45.7 m (100 to 150 ft) from the centerline of the roadway) at a height of 1.5 m (5 ft) above ground level. The duration of the measurement time ranged from fifteen to thirty minutes. Noise levels for locations where the project roadway intersects an existing highway system were determined by modeling the existing traffic volume (1998 traffic data) as discussed below.

Noise levels ranged in the mid to upper 40 Leq(h) level adjacent to unimproved county roads and ranged in the upper 50 Leq(h) to mid 60 Leq(h)₎ level near existing highways. Noise levels exceeding the FHWA impact criteria currently occur at several residences located adjacent to N-2.

7.0 PREDICTED NOISE LEVELS

7.1 Prediction Methodology

The procedures included in the FHWA Traffic Noise Model perform an analysis of traffic noise in terms of traffic parameters (vehicle type and speed), roadway design and receptor characteristics. These parameters are input into the computer model which provides the noise level estimate. All noise levels referred to in this study are exterior noise levels.

Detailed engineering regarding the exact alignment and grade of the beltway alternatives, cut and fill areas, and intersection design is beyond the scope of the current level of the beltways study. As such, the traffic engineer's best estimates of these parameters have been incorporated into the model, therefore, these results must be considered preliminary. Further analysis of the noise impacts and recommended mitigation should be completed using more detailed design information if any of the Build options are selected.

7.2 Traffic Parameters

Beltway Alternatives. The traffic volume used in this study is based upon 2030-Build projections developed by the Lincoln-Lancaster County Planning Department (refer to Appendix C-A). Typically, roadway projects are modeled using 20 year traffic projections, however, the 2030 data was developed to correspond to the Build Out Scenario (BOS2) Land Use Plan adopted by the City of Lincoln. This plan assumes a population of 374,630. Traffic volumes within the diamond interchanges along the beltway were not modeled by the City and therefore were not available for the noise model. However, noise at the interchanges would not be considered significant due to the low volumes and reduced speeds of traffic within the interchanges in comparison with the high volumes and high speeds through the interchange.

The "peak-hour" traffic parameters used reflect 10 percent of the 2030-Build ADT.

Existing Roadways. The 2020-No-Build traffic volumes from Interim Report No. 3 (WSA, revised 1999) were compared to the 2030-Build projections developed by the Lincoln-Lancaster County Planning Department.

The "peak-hour" traffic parameters used reflect 10 percent of the 2020 No-Build and 2030- Build ADT.

The following Federal Highway Administration (FHWA) criteria for automobiles, medium trucks and heavy trucks were used in determining the vehicle mix (Table C.3) for the study roadways.

• Automobiles: all vehicles with two axles and four tires- primarily designed to carry nine or fewer people (passenger cars, vans) or cargo (vans, light trucks)- generally with gross vehicle weight less than 44 kilonewtons (9,900 lb)
• Medium trucks: all cargo vehicles with three or more axles- generally with gross vehicle weight between 44 kilonewtons (10,000 lb) but less than 116 kilonewtons (26,000 lb)
• Heavy trucks: all cargo vehicles with three or more axles- generally with gross vehicle weight more than 116 kilonewtons (26,000 lb)

Table C.3

VEHICLE MIX PERCENTAGE

¹ Provided by HWS Consulting Group, Inc.

² Provided by Nebraska Department of Roads

7.3 Predicted Noise Levels

Existing Roadway Noise Levels. The east beltway alternatives are projected to cause an increase in traffic volume along certain existing roadways (some of which are not located within the beltway study area). For these locations, the 2030-Build projected traffic Leq(h) noise level at each receptor has been compared to the 2020 No-Build traffic Leq(h) noise level to determine future noise impacts for receptors adjacent to the existing roadways. The analysis indicates that noise levels will generally increase along existing roadways, however, no noise impacts are predicted (refer to Tables C.4-C.11). The locations of the receptors are shown in Figures C-1 to C-6 which include a base photograph from April 1997.

It should also be noted that some of the 2020 predicted levels for the No-Build scenario were as much as 6 dB lower than the lowest 1999 field measurements of ambient noise. This is most likely due to the fact that the model does not account for other ambient noise in the area.

Beltway Noise Levels. The 2030-Build projected traffic Leq(h) noise level at each receptor has been compared to the 1999-Existing traffic Leq(h) noise level to determine future noise impacts for receptors adjacent to the beltway alignments. The predicted noise levels for these receptors are summarized in Tables C.12 to C.17. Tables C.12 to C.14 are the south beltway alternative under different traffic volume assumptions corresponding to connections with EC-1, EM-1 and EF-1. Tables C.15 to C.17 are the three east beltway alternatives. The location of the receptors are shown on the Exhibits in the main body of the EIS.

Table C.4

EC-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on 27^TH Street between Pine Lake Road and Yankee Hill Road

¹ NAC level is 72 Leq(h)

² NAC level is 67 Leq(h)

Table C.5

EC-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on Van Dorn Street between 84^th Street and 98^th Street

Table C.6

EC-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on Old Cheney Road between 84^th Street and 98^th Street

Table C.7

EM-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on Old Cheney Road between 84^th Street and 98^th Street

Table C.8

EM-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on 70^th Street between Yankee Hill Road and Saltillo Road

Table C.9

EF-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on Old Cheney Road between 84^th Street and 98^th Street

Table C.10

EF-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on 70^th Street between Yankee Hill Road and Saltillo Road

Table C.11

EF-1 ALTERNATIVE

PREDICTED NOISE LEVELS

on 70^th Street between Old Cheney Road and N-2

Table C.12

SM-4/EC-1 ALTERNATIVE

PREDICTED BELTWAY NOISE LEVELS

Table C.13

SM-4/EM-1 ALTERNATIVE

PREDICTED BELTWAY NOISE LEVELS

Table C.14

SM-4/EF-1 ALTERNATIVE

PREDICTED BELTWAY NOISE LEVELS

Table C.15

EC-1 ALTERNATIVE

PREDICTED BELTWAY NOISE LEVELS

Table C.16

EM-1 ALTERNATIVE

PREDICTED BELTWAY NOISE LEVELS

Table C.17

EF-1 ALTERNATIVE

PREDICTED BELTWAY NOISE LEVELS

7.4 Predicted Noise Contours

Based upon review of the noise levels predicted for the existing receptors and by inserting "dummy"receptors along the beltway alignments, the 66 Leq(h) dBA noise contour which represents the residential noise impact level as discussed in Section 4.0 has been estimated. The location of this contour is useful for land-use planning.

The area adjacent to the beltway alignments which will be within the 66 Leq(h) dBA contour will vary depending upon the traffic (volume and type) and topography. Along the SM-4 alternative the contour ranges from 51.8 to 76.2 m (170 to 250 ft) from the roadway centerline, on the EC-1 and EM-1 alignments the contour ranges from 45.7 to 57.9 m (150 to 190 ft) and along the EF-1 alignment the contour is approximately 45.7 m (150 ft) from the centerline. These distances will increase near the major intersections.

8.0 NOISE ABATEMENT

8.1 Noise Mitigation Measures

In accordance with the NDOR Noise Abatement Policy, noise abatement measures must be considered where predicted traffic noise levels approach or exceed the noise abatement criteria, or when the predicted traffic noise levels substantially exceed the existing noise levels (i.e. 15 dBA). The noise mitigation measures considered during this study are summarized below.

8.1.1 Shifting the Roadway Alignment Horizontally

A shift in the horizontal alignment can be incorporated into a project to reduce traffic noise where receptors are typically on one side of the roadway alignment and the topography is acceptable. Since sound intensity decreases with distance, shifting the roadway away from the receptor will reduce noise levels. Shifting the horizontal alignment of the roadway appears to be a feasible method to mitigate the traffic noise at nine of the impacted receptors, however, a cost analysis could not be completed during this level of study. A more detailed analysis to determine the exact distance of the roadway shift, the starting and ending points and the construction costs will be necessary to determine if this mitigation method is reasonable.

8.1.2 Constructed Noise Barriers

A noise barrier, either a wall made of concrete or wood products or an earthen berm, may be constructed to break the line-of-sight to the receptor. To be effective, a noise barrier must be continuous and have substantial length and height. In accordance with the NDOR Policy, a noise barrier must be feasible from an engineering standpoint and reasonable from a cost, effectiveness, and access standpoint to be considered.

Barrier Feasibility Criteria. Barriers are considered feasible if the insertion loss (reduction in traffic noise at a point 3.0 m (10 ft) from the residence) is at least five decibels. The following items are considered to evaluate the feasibility:

• Can a barrier be built to fit the topography?
• Is the exposed height of the barrier no more than 4.9 m (16 ft), except for short lengths?

• Can the barrier be located beyond the clear recovery zone or be incorporated into existing highway barriers?
• Are other significant noise sources present?

Barriers not meeting these criteria are not feasible and further evaluation is not conducted.

Noise barriers for thirteen locations appear to be feasible based upon the current alignments, therefore, a reasonableness test was conducted for each of these locations.

Barrier Reasonableness Criteria. Reasonableness is judged on a point system based upon the four criteria listed below. Barriers with a point total of 9 or less are judged to be not reasonable.

• The noise abatement must be cost effective. Cost effectiveness is defined as cost per protected receptor.
  • < $18,000/receptor = 4
  • $28,000 to $23,000/receptor = 3
  • $23,000 to $28,000/receptor = 2
  • $28,000 to $30,000/receptor = 1

(Unit costs for construction of earthen barriers of $3.92 per cubic meter ($3.00 per cubic yard) of soil and $190.00 per square meter ($18 per square ft) for manufactured walls was used in the cost analysis. If the cost per receptor is above $30,000, the barrier will be considered not reasonable).

• The change in computed noise levels between the design year and the existing will equal or exceed 3 decibels (a barely perceptible change).
  • > 3 decibels = 4
  • 3 decibels = 3
  • 2 decibels = 2
  • < 2 decibels = 1

• The impacted receptor or platted area preceded the FHWA approval of the environmental document for initial highway construction.
  • > 80 percent = 4
  • 50-80 percent = 3
  • 30-50 percent = 2
  • <30 percent = 1

• It is considered unreasonable if the barrier provides noise abatement on a highway with partial or no control of access.
  • Full access control = 4
  • ½ mile access control = 2
  • ¼ mile access control = 1
  • < ¼ mile access control = 0

8.2 Noise Abatement Analysis for Impacted Receptors along the SM-4 Alternative

NOISE ABATEMENT FEASIBILITY REVIEW: SM-4 ALTERNATIVE

Notes: 1 - Alignment shifted to eliminate noise impact (less than 66 Leq(h) dBA or below significant increase of 15 dBa).

2 - Can the exposed height of a barrier be built 4.9 meters (16 feet) or less?

3 - Other noise sources include other roadways that contribute to noise.

Noise barriers for two locations appear to be feasible based upon the current alignment of SM-4, therefore, a reasonableness test was conducted for each of these locations.

Barrier Reasonableness Test for SM-4 Receptor 12. An earthen berm approximately 3.7 m (12 ft) high extending 66.4 m (218 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

Barrier Reasonableness Test for SM-4 Receptors 25, 27, 28, 29, 31. A manufactured wall ranging in height of 3.0 to 3.4 m (10 to 11 ft) extending 769.6 m (2,525 ft) in length along the right-of-way was analyzed. Based a cost/receptor in excess of $30,000, as summarized below, the wall is not reasonable and will not be included for further study.

8.3 Noise Abatement Analysis for Impacted Receptors along the EC-1 Alternative

Notes: 1 - Alignment shifted to eliminate noise impact (less than 66 Leq(h) dBA or below significant increase of 15 dBa).

2 - Can the exposed height of a barrier be built 4.9 meters (16 feet) or less?

3 - Other noise sources include other roadways that contribute to noise

Noise barriers for four locations appear to be feasible based upon the current alignment of EC-1, therefore, a reasonableness test was conducted for each of these locations.

Barrier Reasonableness Test for EC-1 Receptor 17. An earthen berm ranging in height of

3.4 to 4.27 m (11 to 14 ft) extending 189.3 m (621 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

Barrier Reasonableness Test for Receptor 19. A manufactured wall ranging in height of

3.4 to 4 m (11 to 13 ft) extending 110.3 m (362 ft) in length along the right-of-way was analyzed. Based a cost/receptor in excess of $30,000, as summarized below, the wall is not reasonable and will not be included for further study.

Barrier Reasonableness Test for EC-1 Receptor 55. An earthen berm at a height of 3.7 m (12 ft) extending 132.3 m (434 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

Barrier Reasonableness Test for Receptor R-56. An earthen berm at a height of 3.7 m (12 ft) extending 142.6 m (468 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

8.4 Noise Abatement Analysis for Impacted Receptors along the EM-1 Alternative

Table C.20

NOISE ABATEMENT FEASIBILITY REVIEW: EM-1 ALTERNATIVE

Notes: 1 - Alignment shifted to eliminate noise impact (less than 66 Leq(h) dBA or below significant increase of 15 dBa).

2 - Can the exposed height of a barrier be built 4.9 meters (16 feet) or less?

3 - Other noise sources include other roadways that contribute to noise

Noise barriers for two locations appear to be feasible based upon the current EM-1 alignment, therefore, a reasonableness test was conducted for each of these locations:

Barrier Reasonableness Test for EM-1 Receptors 6, 7 and 8. A manufactured wall ranging in height of 3.4 to 5.8 m (11 to 19 ft) extending 437.7 m (1,436 ft) in length along the right-of-way was analyzed. Based a cost/receptor in excess of $30,000, as summarized below, the wall is not reasonable and will not be included for further study.

Barrier Reasonableness Test for EM-1 Receptors 23 and 24 (Crooked Creek Golf Course). An earthen berm ranging in height of 2.4 to 3.0 m (8 to 10 ft) extending 289 m (948 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

8.5 Noise Abatement Analysis for Impacted Receptors along the EF-1 Alternative

Noise Abatement Feasibility Review: EF-1 Alternative

Notes: 1 - Alignment shifted to eliminate noise impact (less than 66 Leq(h) dBA or below significant increase of 15 dBa).

2 - Can the exposed height of a barrier be built 4.9 meters (16 feet) or less?

3 - Other noise sources include other roadways that contribute to noise

Noise barriers for five locations appear to be feasible based upon the current alignment of EF-1, therefore, a reasonableness test was conducted for each of these locations:

Barrier Reasonableness Test for EF-1 Receptor 2. A manufactured wall ranging in height of

3.0 to 4.3 m (10 to 14 ft) extending 187.5 m (615 ft) in length along the right-of-way was analyzed. Based a cost/receptor in excess of $30,000, as summarized below, the wall is not reasonable and will not be included for further study.

Barrier Reasonableness Test for EF-1 Receptors 5, 6, 7, 8, 9 and 10. A manufactured wall ranging in height of 2.1 to 2.7 m (7 to 9 ft) extending 860.8 m (2,824 ft) in length along the right-of-way was analyzed. Based a cost/receptor in excess of $30,000, as summarized below, the wall is not reasonable and will not be included for further study.

Barrier Reasonableness Test for EF-1 Receptor 12 . An earthen berm ranging in height of

2.4 to 3.0 (8 to 10 ft) extending 196.9 m (646 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

Barrier Reasonableness Test for EF-1 Receptor 13. An earthen berm ranging in height of

3.4 to 4.6 m (11 to 15 ft) extending 147.2 m (483 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

Barrier Reasonableness Test for EF-1 Receptors 24 and 25. An earthen berm ranging in height of 4.0 to 4.9 m (13 to 16 ft) extending 98.5 m (323 ft) along the right-of-way was analyzed. Based upon the reasonable test summary below, the berm should be included for further study.

9.0 CONSTRUCTION NOISE

Construction noise levels are typically a function of the scale of the project, the phase of construction, the condition of the equipment and its operating cycles, and the number of construction equipment units operating simultaneously. There are several measures that can be adopted to reduce construction noise impacts.

• Constructing the noise barrier early in construction

If the recommended noise barrier is publically acceptable, its construction at an early phase could mitigate potential construction-related noise impacts.

• Community awareness

Letting people know when construction noise may occur and the duration helps the public anticipate it and plan their activities accordingly. This information is generally submitted to the local news media.

• Design considerations

This includes designating haul routes that would avoid sensitive areas and constructing permanent and temporary noise barriers.

• Controlling noise at the source

Source control can be accomplished by specifying proper muffler systems and using wheeled equipment instead of tracked equipment whenever possible. Operation of stationary equipment such as air compressors or generator as far away as possible from sensitive receptors will reduce noise impacts and erection of temporary noise barriers are considerations to mitigate noise. Source control provisions can be included in contract documents.

• Time and activity constraints

This includes limiting work hours so activity is not occurring during the hours of sleep or holidays. Exceptions due to weather, schedule, and a time-related phase of the construction work could occur.

10.0 SUMMARY

Traffic noise impacts are predicted to occur under the 2030-Build scenario for the four proposed beltway alignments. The only noise impacts predicted under the No-Build scenario occur at several residences located adjacent to N-2.

Noise mitigation measures determined to be feasible and reasonable include shifting the horizontal roadway alignment and/or installation of noise barriers. The preliminary evaluation indicates noise abatement measures should be considered at fourteen locations as summarized below. All proposed barriers provide an insertion loss of a least 5 dBA below the predicted level. Roadway alignment shifts will provide a reduction in the predicted traffic noise level increase to less than 15 dBA over existing conditions.

SM-4 Alternative Receptor R-11. Shift horizontal roadway alignment of roadway north approximately 36.6 m (120 ft).

SM-4 Alternative Receptor R-12. Installation of an earthen berm at a height of 3.7 m (12 ft) and a length of 8.53 m (28 ft).

EC-4 Alternative Receptor R-17. Installation of an earthen berm ranging in height from 3.4 to 4.3 m (11 to 14 ft) and a length of 189.3 m (621 ft).

EC-1 Alternative Receptor R-42. Shift horizontal roadway alignment of roadway west approximately 15 m (50 ft).

EC-1 Alternative Receptor R-55. Installation of an earthen berm at a height of 3.7 m (12 ft) and a length of 132.3 m (434 ft).

EC-1 Alternative Receptor R-56. Installation of an earthen berm at a height of 3.7 m (12 ft) and a length of 142.6 m (468 ft).

EM-1 Alternative Receptor R-17. Shift horizontal alignment of roadway 91 to 107 m (300 to 350 ft) east.

EM-1 Alternative R-23, 24 (Crooked Creek Golf Course). Installation of an earthen berm at a height ranging from 2.4 to 3.0 m (8 to 10 ft) and a length of 289 m (948 ft). Shift horizontal alignment of roadway 22.9 m (75 ft) west.

EM-1 Alternative R-35. Shift horizontal alignment of roadway 120 m (400 ft) east.

EF-1 Alternative R-14. Installation of an earthen berm at a height ranging from

2.4 to 3.0 m (8 to 10 ft) and a length of 196.9 m (646 ft). Shift horizontal alignment of the roadway 30 m (100 ft) west.

EF-1 Alternative R-15. Installation of an earthen berm ranging in height from

3.4 to 4.6 m (11 to 15 ft) and a length of 147.2 m (483 ft). Shift roadway alignment

7.6 to 9.1 m (25 to 30 ft) west.

EF-1 Alternative R-27. Installation of an earthen berm ranging in height from

4.0 to 4.9 m (13 to 16 ft) and a length of 98.5 m (323 ft).

EF-1 Alternative R-33. Shift roadway alignment 61 m (200 ft) east.

EF-1 Alternative R-34. Shift roadway alignment 76.2 m (250 ft) east.

There are 26 remaining residences which are impacted, but for which it appears there are no feasible or reasonable noise abatement measures available. These include 5 on SM-4; 10 on EC-1; 5 on EM-1; and 6 on EF-1. Further evaluation of noise abatement measures should be conducted during final roadway design.

11.0 REFERENCES

Highway Traffic Noise Analysis and Abatement, Policy and Guidance, FHWA, June 1995

Noise Analysis and Abatement Policy, Nebraska Department of Roads, May 1998

23 Code of Federal Regulations (CFR) Part 772, 1982.

South and East Beltways Study, Interim Report No. 3. Wilbur Smith Associates. (Revised March) 1999. Lincoln, Nebraska.

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Appendix C-A

2030 Average Daily Traffic Volume