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Noise Tidbits

These "tidbits" are intended to supplement the Caltrans Noise Protocol (October, 1998) by providing some "easy" sequential guidance.

1)Identify whether the analysis uses  the 1998 Noise Protocol or the State's previous guidance. Main differences: 1 dBA (new)  vs  2 dBA (previous guidance) approach criteria and cost per receptor (new) vs reasonable cost (previous guidance). Either way, the NEPA document must document which criteria is being used and must remain consistent throughout the document.

2) Is the project considered a TYPE I project? If YES,PROCEED! If NO, STOP and document that the project IS NOT a TYPE I.

3) Measure existing noise as well as modeling noise based on 20 year (design year) projection. Measurements should be taken in "frequent" human use areasincluding any applicable commercial areas. Note: Community Noise Levels (CNELs) are not recognized by FHWA.

4) Is noise considered to be approaching or exceeding any of the Noise Abatement Criteria (NAC) for category A thru E?

5) Are noise levels considered to be a substantial increase ( >12 dBA or greater)?

6) If you answer YES to question # 4 or # 5, you have identified a noise impact for which you now need to consider* abatement based upon a Reasonable and Feasible (R/F) analysis. If you answer NO to questions # 4 & #5, STOP and document that no noise impacts were identified. Therefore, no more "consideration"of abatement is needed.

7) Using the various factors for R/F (cost, minimum 5 dBA reduction, etc.) as discussed in the Protocol, determine if abatement is warranted. (You are encouraged to consider the facilities ultimate traffic/geometrics so any abatement could be designed/constructed "now" in its final location/height to minimize future waste and delay!)

8) Furnish the results of the R/F analysis in a table (see next page or TeNS pg.176) that includes: receptor location(s); existing noise; projected noise; range of wall and/or berm heights; cost per receptor; with an asterisk/bolding, etc. of the height that abatement is considered as R/F.

9) Use this table in the NEPA document with a discussion summarizing the results of your R/F analysis. Be sure to state in the NEPA document, "If pertinent parameters change substantially during the final project design, the preliminary noise abatement/mitigation design may be changed or eliminated from the final projects design. A final decision of the construction of the noise/abatement will be made upon completion of the project design and public input."

At the time the information is furnished to the public in a NEPA document and/or for a public hearing, the R/F analysis shall be completed with the State's preliminary proposal or non-proposal of abatement. As stated in #9 above, the final decision could change BUT the proposed abatement should be 99% set by NEPA document circulation time.  NOTE: Any changes in the "approved" NEPA documents abatement measure(s) "requires" FHWA review/approval.

MISC

If a property owner (commercial, motel, park officials, etc.) does not wish abatement, written documentation of their decision is needed and should be included in the R/F Report.

Prior to a public "hearing," consider mailing noise information (sketch, general info, etc.) to property owners, especially those with abatement proposed and/or on their private property, alerting them to the hearing and encouraging them attend for more details  and/or ask them to respond in writing with accept/decline "proposed" abatement.

RECEPTOR NOISE LEVELS AND NOISE BARRIER TABLE

Receiver I.D. No.
#

Type, Location or Address

Approx. # of
Receptors

Offset
Distance to Centerline

Existing Noise Levels
Leq (h), dBA

Predicted Noise Levels
Leq (h), dBA
(Year)

Heights of Barrier
(Indicate whether
Wall and/or Berm)

Benefitted Receiver Cost

Measured

Calculated

No Build

Build

1.8 m
(6 ft.)

2.4 m
(8 ft.)

3.0 m
(10 ft.)

4.9 m
(16 ft.)

                         

Use an asterisk or shading or bolding in the applicable row/column to help highlight the specific abatement which is considered to be R/F.

Also TeNS, other examples are available in the TeNS pages 172, 173, 175 and 176.

The intent of the table is to provide easy to read information per the FHWA Technical Advisory for such items as: receptors location, existing noise, projected noise, "range" of wall heights and cost of barrier. The "highlighting" of the location(s) considered to be R/F is also needed to help propose a conclusion for the information presented.                                         

FHWA NOISE ABATEMENT CRITERIA

Activity
Category

dBA
Leq

Description of Land Use Activity Areas

A

57
(exterior)

Lands on which serenity and quiet are of extra-ordinary significance and serve an important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose.

B

67
(exterior)

Picnic areas, recreation areas, playgrounds, active sports areas, parks, residences, motels, hotels, schools, churches, libraries and hospitals.

C

72
(exterior)

Developed lands, properties or activities not included in categories A or B above.

D

Undeveloped lands.

E

52
(interior)

Residences, motels, hotels, public meeting rooms, schools, churches, libraries, hospitals and auditoriums.

NOTE:  primary consideration is given to exterior areas (Category A, B or C) where frequent human activity occurs.  However, interior areas (Category E) are used if exterior areas are physically shielded from the roadway, or if there is little or no human activity in exterior areas adjacent to the roadway.  

These "tidbits" are intended to supplement the Caltrans Noise Protocol (October, 1998) by providing some "easy" sequential guidance.

1)Identify whether the analysis uses  the 1998 Noise Protocol or the State's previous guidance. Main differences: 1 dBA (new)  vs  2 dBA (previous guidance) approach criteria and cost per receptor (new) vs reasonable cost (previous guidance). Either way, the NEPA document must document which criteria is being used and must remain consistent throughout the document.

2) Is the project considered a TYPE I project? If YES,PROCEED! If NO, STOP and document that the project IS NOT a TYPE I.

3) Measure existing noise as well as modeling noise based on 20 year (design year) projection. Measurements should be taken in "frequent" human use areasincluding any applicable commercial areas. Note: Community Noise Levels (CNELs) are not recognized by FHWA.

4) Is noise considered to be approaching or exceeding any of the Noise Abatement Criteria (NAC) for category A thru E?

5) Are noise levels considered to be a substantial increase (>12 dBA or greater)?

6) If you answer YES to question # 4 or # 5, you have identified a noise impact for which you now need to consider* abatement based upon a Reasonable and Feasible (R/F) analysis. If you answer NO to questions # 4 & #5, STOP and document that no noise impacts were identified. Therefore, no more "consideration"of abatement is needed.

7) Using the various factors for R/F (cost, minimum 5 dBA reduction, etc.) as discussed in the Protocol, determine if abatement is warranted. (You are encouraged to consider the facilities ultimate traffic/geometrics so any abatement could be designed/constructed "now" in its final location/height to minimize future waste and delay!)

8) Furnish the results of the R/F analysis in a table (see next page or TeNS pg.176) that includes: receptor location(s); existing noise; projected noise; range of wall and/or berm heights; cost per receptor; with an asterisk/bolding, etc. of the height that abatement is considered as R/F.

9) Use this table in the NEPA document with a discussion summarizing the results of your R/F analysis. Be sure to state in the NEPA document, "If pertinent parameters change substantially during the final project design, the preliminary noise abatement/mitigation design may be changed or eliminated from the final projects design. A final decision of the construction of the noise/abatement will be made upon completion of the project design and public input."

At the time the information is furnished to the public in a NEPA document and/or for a public hearing, the R/F analysis shall be completed with the State's preliminary proposal or non-proposal of abatement. As stated in #9 above, the final decision could change BUT the proposed abatement should be 99% set by NEPA document circulation time.  NOTE: Any changes in the "approved" NEPA documents abatement measure(s) "requires" FHWA review/approval.

MISC

If a property owner (commercial, motel, park officials, etc.) does not wish abatement, written documentation of their decision is needed and should be included in the R/F Report.

Prior to a public "hearing," consider mailing noise information (sketch, general info, etc.) to property owners, especially those with abatement proposed and/or on their private property, alerting them to the hearing and encouraging them attend for more details  and/or ask them to respond in writing with accept/decline "proposed" abatement.

RECEPTOR NOISE LEVELS AND NOISE BARRIER TABLE

Receiver I.D. No.
#

Type, Location or Address

Approx. # of
Receptors

Offset
Distance to Centerline

Existing Noise Levels
Leq (h), dBA

Predicted Noise Levels
Leq (h), dBA
(Year)

Heights of Barrier
(Indicate whether
Wall and/or Berm)

Benefitted Receiver Cost

Measured

Calculated

No Build

Build

1.8 m
(6 ft.)

2.4 m
(8 ft.)

3.0 m
(10 ft.)

4.9 m
(16 ft.)

                         

Use an asterisk or shading or bolding in the applicable row/column to help highlight the specific abatement which is considered to be R/F.

Also TeNS , other examples are available in the TeNS pages 172, 173, 175 and 176.

The intent of the table is to provide easy to read information per the FHWA Technical Advisory for such items as: receptors location, existing noise, projected noise, "range" of wall heights and cost of barrier. The "highlighting" of the location(s) considered to be R/F is also needed to help propose a conclusion for the information presented.

FHWA NOISE ABATEMENT CRITERIA

Activity
Category

dBA
Leq

Description of Land Use Activity Areas

A

57
(exterior)

Lands on which serenity and quiet are of extra-ordinary significance and serve an important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose.

B

67
(exterior)

Picnic areas, recreation areas, playgrounds, active sports areas, parks, residences, motels, hotels, schools, churches, libraries and hospitals.

C

72
(exterior)

Developed lands, properties or activities not included in categories A or B above.

D

Undeveloped lands.

E

52
(interior)

Residences, motels, hotels, public meeting rooms, schools, churches, libraries, hospitals and auditoriums.

NOTE:  primary consideration is given to exterior areas (Category A, B or C) where frequent human activity occurs.  However, interior areas (Category E) are used if exterior areas are physically shielded from the roadway, or if there is little or no human activity in exterior areas adjacent to the roadway.

Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000