Updated July 2017
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 2016.
A tool has been developed to view and filter the data within the nationwide noise barrier inventory. This tool allows the user to view all 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.
In discussing noise barrier trends, the 1963 to 2016 time frame will be used, with a focus on the period of time from 2014-2016, which is the most recent period collected and is the basis for this update.
The 1963-2016 data reflects the flexibility SHAs have in noise abatement decision-making:
The data also shows that from 1963 through the end of 2016:
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 the noise program began in 1963. Noise barriers (walls and berms) have been the preferred form of abatement used by SHAs of the options available under 23 CFR 7721. Noise barrier materials include concrete, block, wood, metal, earth berms, brick, fiberglass and plastics, composites, and combinations of all these materials.
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 2016 dollars):
From 2014 to 2016 (the current reporting period):
From 2011 to 2013 (the previous reporting period):
From 1963 to 2016 (the period of time since the noise program began):
Average Unit Costs (combining all materials and barrier types):
Type II Barrier Construction (since 1963):
Materials Used (since 1963):
Some states continue to report difficulty determining noise barrier costs with the increase in use of alternative project delivery approaches such as design-build. 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. During this reporting period, seven barriers (totaling 94,129 square feet) were reported as ‘demolished and replaced’. However, the replacement barriers were not always the same material, height or length since they were now based on the latest regulation (23 CFR 772) and on the Traffic Noise Model version 2.5.
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.
Additionally, California did not provide data from 1999 through 2004 and limited data for the 2005 through 2007 inventory update. This lack of information affects the quality of data for these years, since California’s reported noise barriers comprise approximately 16% of total US noise barriers by area and 19% of total US noise barriers by length.
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.
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 $162 million of highway program funds annually6 for this form of noise abatement. The average annual spending for this reporting period (2014-2016) was $224 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 (19%) for Type II projects7.
1 This is a noise barrier inventory per 23 CFR 772.13(f), as such costs and types of insulation for NAC D are not reported. In addition, no SHA has utilized the acquisition of property or land as a noise abatement measure.
2 From 2014 to 2016, 817,759 square feet of barriers had no NAC reported. This is 0.35% of the total square footage for this reporting period.
3 From 2014 to 2016, 1,706,291 square feet (7.4%) of barriers did not have a surface treatment reported.
4 4% of barriers did not report a material.
5 0.2% (549,551 square feet) of barriers were reported as having ‘Both’ absorptive and reflective surfaces. 71% of barriers reported no surface treatment.
6 There are no costs reported for 1963-1971, these years are excluded from the average.
7 Barriers reported by SHAs may not have a Type assigned, or may be listed as using State (7%), Toll (1%), County, Other (2%), Local, or a Combination of funds; these make up the remaining 11% of barrier expenditures since 1963.