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Last Updated: Tuesday, April 15, 2008 10:13 AM

Noise and Vibration Studies

(3/14/08)"Annotated Noise Study Report (NSR)"

The Annotated Noise Study Report Outline is designed to provide a consistent format for the noise impact analysis required on highway projects. This outline should be used for all Type I projects that require NEPA compliance. The noise specialist should work closely with the Project Engineer to insure that all pertinent noise study information is include in the Noise Abatement Decision Report (NADR). Click here to access the "Annotated Noise Study Report (NSR)"

Caltrans Traffic Noise Analysis Protocol (Protocol) - dated August 2006

2006 Protocol.zip (1.7 mb) includes 2006 Protocol, FHWA approval letter and NADR template.

Effective date for Protocol (August 2006) implementation are on noise studies started on or after October 1, 2006. In August of 2006 the FHWA approved a much-revised version of the 1998 Protocol for use on projects on the state highway system. This revision was intended to provide a more concise document for ease of use by non-technical readers. A major change in the policy document eliminates any significant discussion of NEPA or CEQA and focuses exclusively on Federal Code (Title 23 Part 772). The Draft environmental document will address other regulatory commitments regarding noise impacts. The following are some of the more significant changes to the Protocol.

1. The Protocol now requires the use of a District Noise Abatement Decision Report (NADR) during the environmental process to document the following:
   1. Noise abatement reasonableness allowances - from the Noise Study Report
   2. Acoustic feasibility of noise abatement
   3. Locations and dimensions of evaluated noise barriers
   4. Engineering estimates of acoustically feasible noise abatement
   5. Other construction considerations related to noise barriers - i.e. known utilities, etc.
   6. Effects of abatement on other environmental resources - i.e. scenic views, biological, etc.
   7. The NADR recommendations are incorporated into the draft environmental document for public review. If the project does not have a publicly reviewed environmental document, the NADR can be used to solicit public comment. The NADR recommendation will become the final abatement recommendation unless changed during public review. The final noise abatement decision is ultimately included in the approved environmental document
   8. Click here to see the NADR frequently asked questions
2. Type I Impacts were revised as follows:
   1. Timing for consideration - added language to include FONSI, Cat Ex
   2. Type I Project - added "full length" to ramp widening criteria
   3. Type I Definition - slightly revised to better capture intent
   4. Impact Prediction - added language to avoid model exceeding 500 ft
   5. Includes language to notify local agencies about predicted noise levels for land use planning.
3. Defines FHWA TNM 2.5 as approved modeling software for noise studies on the state highway system.
4. Extended abatement "life cycle" to a useful life of 20 years rather than the previous 15 years.
   
5. Defines Project Development Team as abatement decision maker for final environmental document.
6. Cost - establishes a new 2006 base allowance of $32k with annual adjustments determined by most recent annual Construction Price Index.

Some small typographical errors have been found in the new Protocol.  These are being accumulated and a revision will be forthcoming.  No major problems but as an example the requirement of a majority of affected residents approval for a wall was omitted from the Type I discussion.  This was an error and will be corrected.

Construction Cost Index for Noise Study - The 2005 annual cost index increased dramatically to 268.2 from 128.6 in 1998. As a result, we are updating the base reasonable allowance defined in the Protocol for noise abatement from $26,000 to a rounded value of $32,000. This value should be used for all projects with noise studies started on or after April 1, 2006.

Implementation of Traffic Noise Model (TNM 2.5) - The Federal Highway Administration (FHWA) published a Notice of Proposed Rulemaking on August 20, 2004 to change the national traffic noise model required for use on Federal Aid projects to TNM. In an agreement reached with FHWA, Caltrans has agreed to require all new project noise studies, beginning after January 15, 2005, to use TNM version 2.5 or later for acoustic modelling of traffic noise. The exception to this requirement is for a reevaluation noise study of a project that was originally modelled using Sound 32 or Sound 2000.

Publications

Noise and Vibration Technical Advisories have been posted at the publications web page.

The following publications pertaining to acoustical and vibration issues are available for downloading:

• Transportation- and Construction-Induced Vibration Guidance Manual, June 2004 (869 KB)
• 2006 Traffic Noise Analysis Protocol (1.7 mb)
• Noise Abatement Decision Report (NADR) (229 kb)
• 1998 Traffic Noise Analysis Protocol (192 kb)
• Technical Noise Supplement (1.8 mb)
• Frequently Asked Questions (104 kb)
• FHWA Noise Studies Process Review Action Plan (279 kb)

More publications can be viewed here.

Software

• Sound 2000 has been released and it is available for downloading in the software section.
• Sound 2000 is an interface upgrade of Sound 32. Sound 32 is the Caltrans version of the FHWA highway noise prediction program which is known as STAMINA 2.0/OPTIMA. Sound 2000 and Sound 32 are public domain software.

Prior downloading the software, read this license. If you agree to the terms of the agreement, click on "I AGREE TO THE ABOVE TERMS" at the end of the page.

Training Resources

The Division of Environmental Analysis has several on-line noise training modules for use by the public.

Recent Activities

Pavement Study

Validation Study

Contacts:

For questions regarding the Noise and Vibration web page, contact the webmaster.