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