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Summary of Noise Barriers Constructed by December 31, 2019

Updated June 2021

The Federal Highway Administration's (FHWA) highway noise regulation (23 CFR 772.13(f)) requires each state highway agency (SHA) to maintain an inventory of all constructed noise abatement measures. The inventory must include the following:

The inventory contains the data supplied by 52 SHAs which includes all 50 States plus Washington DC and Puerto Rico. SHAs provided data for the years 1963 to 2019, especially the period from 2017 to 2019.

Inventory Summary and Tables:

A tool has been developed to view and filter the data within the nationwide noise barrier inventory. This tool allows the user to view the data, or filter down based on the dropdown menus. An option is provided to create a pdf of the search results. State summaries and selected graphs are also available. For any questions please contact us.

This narrative uses the time frame from 1963 to 2019 when discussing noise barrier trends; with a focus on the years 2017-2019, which is the most recent collection period.

The 1963-2019 data reflects the flexibility SHAs have in noise abatement decision-making:

The data also shows that from 1963 through the end of 2019:

Available Noise Abatement Strategies:

The FHWA noise regulation (23 CFR 772):

States balance the abatement's benefits against its costs before making decisions on their use.

Options available outside of FHWAs regulation include local zoning and planning strategies. State and Local governments can implement these methods of noise abatement, which are the most effective:

This inventory reports on abatement strategies implemented by SHAs since 1963, which had the earliest reported noise barrier. Noise barriers (walls and berms) have been the preferred form of abatement used by SHAs of the options available under 23 CFR 772 1. Noise barrier materials include concrete, block, wood, metal, earth berms, brick, fiberglass and plastics, composites, noise absorptive materials, and combinations of all these materials.

Highway Traffic Noise Barrier Construction Trends:

The full dataset submitted by the SHAs is available for searching, viewing, and downloading on the following pages. FHWA summarized the information received from the SHAs into graphs and tables. The data reveals the following information and trends (all costs below are reported in 2019 dollars):

From 2017 to 2019 (the current reporting period):

From 2014 to 2016 (the previous reporting period):

From 1963 to 2019:

Average Unit Costs (combining all materials and barrier types:

Type II Barrier Construction (since 1963):

Materials Used (since 1963):

Items of Note:

During this reporting period some States had difficulty obtaining and reporting data. As such, the information for this reporting period is sometimes incomplete and may be updated during the next reporting period. Some states continue to report difficulty determining noise barrier costs with the increase in use of alternative project delivery approaches such as design-build where barrier costs are not itemized separately. In addition, some states updated their previous inventories with additional information, or cleaned up incorrectly repeated entries.

A new trend that is expected to continue is the demolition and reconstruction of older noise barriers. As the highway system continues to age and require new Type I projects, older barriers may have to be removed or relocated to accommodate new roadway geometries. Barriers totaling 767,903 square feet have been reported as 'demolished and replaced'.

It also is important to note that cost data in the listing are approximate due to varying state practices for estimating costs. The data represent best estimates of SHAs for barrier construction. There may be non-uniformity and/or anomalies in the data due to differences in individual SHA definitions of barrier information and the project features the SHA includes in the reported noise barrier costs. Some years and periods contain more and better quality data than others, this can also affect the averages as presented. Typically, data completeness and quality has improved through time.

Finally, rounding errors may cause some totals to be slightly more or less than 100% in the trend values noted above. For the actual values, please see the following pages, which contain the SHAs datasets.

Summary:

Since 1963, forty-eight states and the Commonwealth of Puerto Rico have constructed highway traffic noise barriers while three (Alabama, District of Columbia and Rhode Island) have not. The most notable trend in highway traffic noise barrier construction is that since SHAs built the first noise barriers they have averaged spending $180 million of highway program funds annually 7 for this form of noise abatement. The average annual spending for this reporting period (2017-2019) was $208 million per year. Since the first highway traffic noise barrier was constructed in 1963, seventy-one (71%) of all spending has been for Type I projects, and nineteen percent (16%) for Type II projects 8.


1 This report only includes noise barriers as a noise mitigation measure. Costs and types of insulation for NAC D have not been reported by any SHA. In addition, no SHA has utilized the acquisition of a buffer zone as a noise abatement measure. Costs and reductions for other avoidance measures, such as re-alignment, have not been documented.

2 Data collection for this reporting period began in early 2020. However, due to the COVID-19 global pandemic some States were unable to report their data or reported partial data for the 2017-2019 collection.

3 From 2017 to 2019, 1,190,898 square feet of barriers had no NAC reported. This is 5.9% of the total square footage for this reporting period.

4 From 2017 to 2019, 4,649,390 square feet (23.12%) of barriers did not have a surface treatment reported. 

5 4% of barriers did not report a material.

6 0.5% (1,413,565 square feet) of barriers were reported as having 'Both' absorptive and reflective surfaces. 64% (172,336,554 square feet) of barriers reported no surface treatment.

7 This average is from 1972 to 2019. Costs for 1963-1971 are either a single barrier or none reported, these years are excluded from the average.

8 Barriers reported by SHAs may not have a Type assigned; or may be listed as using State (6%), Toll (1%), County, Other, Local, or a Combination (4%) of funds. These make up the remaining 13% of barrier expenditures since 1963.

Updated: 10/8/2021
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