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Mn/DOT’s Noise Criteria and Mn/DOT’s Noise Criteria and ModelingModeling
Presenters: Peter Wasko, Mn/DOT Metro District
Mel Roseen, Mn/DOT Environmental Services
Anne Claflin, Minnesota Pollution Control Agency
FHWAMn/DOT MPCA
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Regulatory AgenciesRegulatory AgenciesNoise regulations are either source standards or receiver-based
standards. Department of Natural Resources (DNR)
– The Minnesota DNR has source standards for snowmobiles, motorboats, personal watercraft and off-highway vehicles.
Federal Aviation Administration (FAA) – The FAA has source regulations for commercial jet engines. All
commercial jet engines must meet noise emission criteria prior to being certified for flight.
Federal Highway Administration (FHWA) – The FHWA does not have actual noise standards, but has guidelines of
an L10 of 70 dBA which are used to trip a federal funding mechanism for noise abatement on highway projects.
Federal Railroad Administration (FRA) – Regulation of railroad related noise is the responsibility of the FRA
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Regulatory AgenciesRegulatory Agencies Housing and Urban Development (HUD)
– HUD has noise regulations that establish acceptable noise zones HUD housing projects must fall into.
Occupational Safety and Health Administration (OSHA) – OSHA has regulations to protect against hearing loss in the
workplace. These are “dose standards” that restrict the amount of noise an employee receives over a period of time, such as eight hours.
Local Agency – A local governing agency, such as a city, may or may not have an
ordinance regulating noise levels. Minnesota Pollution Control Agency (MPCA)
– The MPCA has a receiver-based standard intended to limit noise levels and protect the health and welfare of the general public.
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Is there a traffic noise impact?Is there a traffic noise impact?
Do noise levels approach or exceed the FHWA criteria? (Mn/DOT has defined approaching as 1 dBA less than N.A.C.*)
Is there a substantial increase in noise? (Mn/DOT has defined substantial change as a 5 dBA change.)
Do noise levels exceed Minnesota noise standards (if applicable)?
*N.A.C is Noise Abatement Criteria
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23 C.F.R. 77223 C.F.R. 772Mn/DOT Noise Policy for Type I andType II Federal-aid Projects as per
23 CFR 772Purpose:
“The document sets forth procedures for noise studies and noise abatement measures to help protect the public
health and welfare, to supply noise abatement criteria, and to establish requirements for information to be given to local officials for use in the planning and design of Federal-aid
highways approved pursuant to Title 23, United States Code (U.S.C.).
Authority: 23 U.S.C. 109(h), 109(I): 42 U.S.C. 4331, 4332; and 49 CFR 1.48(b).”
www.dot.state.mn.us/environment/noise_analysis/policy.html
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Federal Noise Abatement Federal Noise Abatement CriteriaCriteria
Residential:– L10 of 70 dBA both day and night
Commercial:– L10 of 75 dBA both day and night
L10 is the sound level that would be exceeded 10% of the time ie: 6 minutes of a 1 hour monitoring period
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Minnesota Noise RulesMinnesota Noise Rules
Minnesota Rules Chapter 7030, defines the allowable receiver-based noise limits and source-based motor vehicle noise limits for trucks, motorcycles, and automobiles.
Minnesota Statute 116.07, empowers the MPCA to enforce the limits defined in the state rule.
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Minnesota Noise RulesMinnesota Noise Rules
Noise Area Classifications (NAC)
NAC-1 Residential
NAC-2 Business
NAC-3 Industrial
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Minnesota Noise RulesMinnesota Noise Rules Receiver Based Noise Limits (dBA)
Daytime Nighttime
NAC L50 L10 L50 L10 1 60 65 50 55 2 65 70 65 70 3 75 80 75 80
Minnesota’s noise pollution rules are based on statistical calculations that quantify noise levels according to duration over a one-hour monitoring period. The L10 calculation is the noise level that is exceeded for 10%, or 6 minutes, of the hour, and the L50 calculation is the noise level exceeded for 50%, or 30 minutes, of the hour.
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1 State…. 2 Noise Standards1 State…. 2 Noise Standards
Minnesota State Noise Standards are generally more stringent than FHWA N.A.C.
Not all Federal highway projects need to comply with State Noise Standards
Not all State Projects need to comply with FHWA N.A.C.
Confused yet?
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Common question is.. What Common question is.. What roads are exempted under roads are exempted under
116.07?116.07?
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Exemptions From State Exemptions From State Standards 116.07Standards 116.07
“Existing or newly constructed segment of a highway, provided that all reasonably available noise mitigation measures, as approved by the commissioners of the department of transportation and pollution control agency, are employed to abate noise.”
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Exemptions From State Exemptions From State StandardsStandards
“Except for the cities of Minneapolis and St. Paul, an existing or newly constructed segment of a road, street, or highway under the jurisdiction of a road authority of a town, city, or county, except for roadways for which full control of access has been acquired.”
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Exempt from State Noise Exempt from State Noise StandardsStandards
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Not Exempt from State Noise Not Exempt from State Noise StandardsStandards
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Possibly Exempt from State Possibly Exempt from State Noise StandardsNoise Standards
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How do we determine when How do we determine when and how to mitigate noise?and how to mitigate noise?
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Type I ProjectType I Project
“A proposed project for the construction of a highway at a new location. A physical alteration of an existing highway that significantly changes either the horizontal or vertical alignment or increases the number of through lanes."
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Type II ProjectType II Project
“A proposed federal or federal-aid project for noise abatement on an existing highway. Restrictions placed on the eligibility of Type II projects for federal funding means that retrofit noise mitigation projects will have to rely entirely on state funding.”
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For Type II projects: areas are identified by their ranking in the
2002 (updated in 2008) Noise Priority Study. The Metro District is the only district within
Mn/DOT to fund this program. This program is currently funded at 1.5 million
dollars per year. No federal funding is used.
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MINNOISE, Mn/DOT’s Stamina based computer noise model, is used to predict traffic noise levels for all Type I and Type II projects.
All locations that are predicted to be impacted by traffic noise (greater than a 5 dBA increase over existing, approaching or exceeding the Federal NAC, and/or exceeding State Standards) are considered for noise mitigation.
Analysts should make every effort to qualify these impacted locations for noise mitigation based on reasonability, feasibility and cost effectiveness.
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Partial MnNoise Input Partial MnNoise Input FileFile
noise model for peak traffic TH 52 1 3 2 4 north bound 'CARS' 2213 55 'MT' 102 55 'HT' 83 55 'L'/ 'nb1' 565085.4 256623.5 917.2 0 'nb2' 565098.5 256781.7 913.7 0 'nb3' 565120.3 257044.7 911.7 0 'nb4' 565137.7 257251.7 912.6 0 'nb5' 565150.8 257446.8 914.4 0 'nb6' 565150.8 257644.9 915.5 0 'nb7' 565139.9 257814.9 916.5 0 'nb8' 565123.6 257951.0 917.2 0 'nb9' 565103.9 258079.5 917.8 0
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FHWA TNM ModelFHWA TNM Model
Currently this model (TNM version 2.5) is not approved by Mn/DOT and should not be used in Minnesota at this time.
FHWA is working on TNM 3.0 which is planned to produce L10 and L50 levels. Currently TNM 2.5 produces Leq levels only and Leq levels do not address State Noise Standards.
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What is necessary to model What is necessary to model noise in a given area?noise in a given area?
Roadway alignment-both horizontal and vertical
Elevations- which would include: barrier locations, roadway, existing ground line, and receptors
Traffic information-traffic counts including future traffic growth, projected travel speeds and distributions (vehicle types)
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What is helpful in modeling What is helpful in modeling noise in a given area (cont)noise in a given area (cont)
# of homes/residencies in a given areaShielding effects of obstacles (natural
berms, buildings, vegetation, etc.)Ground surface effects (hard or soft
ground)
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Background Traffic Noise Background Traffic Noise MeasurementsMeasurements
Why are measurements needed?When and how to conduct themDuration # of repetitions Weather Traffic data collection and
documentation
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Modeled Receiver Location Modeled Receiver Location “Rules of Thumb”“Rules of Thumb”
Should be where frequent human use occurs and a lowered noise level would be a benefit
Typical locations should be on the side of the home that faces the roadway (ie: front, back or side yard)
There is not an “exact” rule for receiver location. The analyst should have good reasons for any chosen location(s).
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A
C
E
D
B
F
H I
G
Possible Receiver PlacementPossible Receiver Placement
Right of Way
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MIN 20 Feet
5 FT
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Receiver Height PlacementReceiver Height Placement
Receiver
R.O.W.
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How does Mn/DOT How does Mn/DOT determine if a noise wall is determine if a noise wall is feasible and reasonable?feasible and reasonable?
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Barrier feasibility and Barrier feasibility and reasonability concernsreasonability concerns::
Does Mn/DOT have the required right of way to construct the wall?
Safety concerns such as sight distances and clear zones.
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Buried utilities or utility Buried utilities or utility relocation needs?relocation needs?
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Would hydraulics or drainage Would hydraulics or drainage features on the right of way be features on the right of way be
impacted?impacted?
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Are there concerns with soil types or wetland Are there concerns with soil types or wetland areas in the proposed project area?areas in the proposed project area?
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What are the opinions of the residents about the proposed noise wall? The opinions of the residents are usually considered addressed on the basis of a formal resolution from the city (either for or against).
Material type, color Aesthetic considerations Are there other funding sources available?
(city participation etc?)
Other ConsiderationsOther Considerations
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Example of City ResolutionExample of City Resolution
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Mailer exampleMailer example Minnesota Department of Transportation Metropolitan District Waters Edge
1500 West County Road B2 Roseville, MN 55113 Dear Resident, The Minnesota Department of Transportation (Mn/DOT) proposes to construct a noise wall along the north side of Interstate 35W in Lino Lakes, along Apollo Drive (Anoka County Road 12) between Sunset Road and Savanna Court. This is a one-time opportunity for construction of the wall from Mn/DOT’s noise wall program funds. An informational open house is set from 5 p.m. to 7 p.m. on Monday, October 29, 2007 at Lino Lakes City Hall, 600 Town Center Pkwy in Lino Lakes. Mn/DOT representatives and city officials will be on hand to provide information and visualization materials on the proposed noise wall. Most importantly, the open house aims to solicit your input on the proposed noise wall. The Lino Lakes City Council will use this input to determine if the noise wall will be constructed. As mentioned above, this is a one-time opportunity. Please take time to share your opinion on this noise wall issue. A short opinion form is attached below. You may bring your form to the open house, but additional forms will also be available there. If you’re unable to attend, you may fax your form to me at 651-582-1368, or mail it to me at Mn/DOT, Metro District, 1500 County Road B2, Roseville MN, 55113. This notice has been mailed to residents most affected by the proposed noise wall site. If you have neighbors who are interested in the project, they’re also welcome to attend. Additional handouts will be available at city hall following the meeting. Sincerely, Kent Barnard Mn/DOT Public Affairs ------------------------------------------------------------------------------------------------------------ Name and Address: _____________________________________________ _____________________________________________ _____________________________________________ Please mark one I want the noise wall _____ I do not want the noise wall _____ ADDITIONAL COMMENTS:
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Cost effectiveness:– Will the wall meet a cost effectiveness
value ≤ $3250 per residence per dBA of reduction? (usually based on a $15/sq ft cost ($18/sq ft on bridges))
Acoustical effectiveness:– Will the wall provide a substantial (at least
a 5 dBA) reduction in noise?
Mn/DOT Reasonability CriteriaMn/DOT Reasonability Criteria
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Common Noise Wall MaterialsCommon Noise Wall Materials
40Earth Berm
41Wood post/wood plank
42Concrete post/wood plank
43Concrete
44Glue Laminated wood
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Pavement issuesPavement issues Research regarding the influence of pavement
surface texture on the tire/pavement sound source has been ongoing throughout the years and continues to this day.
The benefits of new advances in paving, such as rubberized asphalt, the use of designed surface texturing etc. are not easily determined.
As a result of unclear benefits pavement type cannot, in and of itself, be considered an alternative to conventional noise mitigation at this time.
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Why Not Plant Trees Instead Why Not Plant Trees Instead of Putting up a Wall?of Putting up a Wall?
“When highway noise mitigation strategies were first being researched there was some thought that dense plantings of vegetation might provide effective blocking of sounds from the highway. However, to be effective at blocking sound there must be complete blockage of the line of sight from the receiver to all noise sources and a great enough mass density to effectively reduce the transmission of sound. A 100 foot swath of this type of planting would provide approx. a 5 dBA reduction. Most vegetative plantings near highways have not been found to meet these prerequisites.”
FHWA Keeping The Noise Down brochure
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How Effective Are Noise How Effective Are Noise Walls?Walls?
Generally the effectiveness of a noise wall depends on the distance between the listener and the noise source, the distance between the listener and the noise wall and the height of the noise wall above the line-of-sight between the listener and the noise source (Path length difference (PDL) is a measure of all these effects).
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Barrier Attenuation and Path Barrier Attenuation and Path Length DifferenceLength Difference
A B
C
Path length difference (PLD) = (A + B) - C
Barrier attenuation increases as the PLD increases
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How Effective Are Noise How Effective Are Noise Walls? (cont)Walls? (cont)
Typically, the benefit due to a noise wall will be greatest for the listeners nearest the noise wall.
For residence located directly behind a 20 foot noise wall a reduction of about 10 dBA would be typical.
This benefit decreases as the listener moves farther away from the wall and is often barely perceptible at distances greater than 500 feet.
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Intervening Ground Intervening Ground Example: Depressed RoadwayExample: Depressed Roadway
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Possible Noise Barrier PlacementPossible Noise Barrier Placement
Clear Zone
Line of sight
Right of Way
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Possible Noise Barrier PlacementPossible Noise Barrier Placement
Clear Zone
Line of sight
Right of Way
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Effect of Partial BarrierEffect of Partial Barrier
-10 dBA -3 dBA 0 dBA
Exposed to half the traffic = -3 dBA
Wall
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Barrier End PointsBarrier End Points(using the 4D rule)(using the 4D rule)
4DDD
4D
Noise Sensitive Receivers
> 80°
> 80°
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Barrier OverlapsBarrier Overlaps
4D
Overlap gap between barriers
D
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Barrier Location ExampleBarrier Location Example
Source
Close to Source (more effective)
Half way between (less effective)
Close to receiver (more effective)
Receiver
Source
ReceiverSource
Receiver
Receiver
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Line Source Attenuation RatesLine Source Attenuation Rates
If the source or the receiver are located more than 10 feet above the ground or when the line of sight averages more than 10 feet above ground use hard site attenuation (i.e. 3 dBA per doubling of distance)
10 Ft
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How Much Do Noise Walls How Much Do Noise Walls Cost?Cost?
Current construction costs are averaging $18 per square foot for a concrete post/ wood plank noise wall.
This translates into a 20-foot high wall costing approximately $1.9 million dollars per mile.
Currently, Mn/DOT still uses a cost of $15/sq ft to determine cost effectiveness
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Does a barrier on one side Does a barrier on one side increase noise for the other?increase noise for the other?
“Residents adjacent to a highway sometimes feel that their noise levels have increased substantially, because of the construction of a noise barrier on the opposite side of the highway. However, field studies have shown that this is not true. If all the noise striking a noise barrier were reflected back to the other side of a highway, the increase would be theoretically limited to 3 dB. In practice, not all of the acoustical energy is reflected back to the other side. Some of the energy goes over the barrier, some is reflected to points other than the homes on the opposite side, some is scattered by ground coverings (for example, grass and shrubs), and some is blocked by the vehicles on the highway. Additionally, some of the reflected energy is lost due to the longer path that it must travel. Measurements made to quantify this reflective increase have never shown an increase of greater than 1-2 dB, an increase that is not perceptible to the human ear. “
FHWA Keeping The Noise Down brochure
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Construction NoiseConstruction Noise
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Needs to be addressed during the Environmental Phase of the projects and during construction.
What can you commit to?What can’t you commit to?Time frame for project (length of
construction phase)Types of equipment (limits on use or
time period)Roadway Construction Noise ModelCommunication with residents is the
key!
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FHWA Roadway Construction ModelFHWA Roadway Construction Model
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Land use planningLand use planning
Minnesota Rule 7030.0030 states: “ No person may violate the standards established in
part 7030.0040, unless exempted by Minnesota Statutes, section 116.07, subdivision 2a. Any municipality having authority to regulate land use shall take all reasonable measures within its jurisdiction to prevent the establishment of land use activities listed in noise area classification (NAC) 1, 2, or 3 in any location where the standards established in part 7030.0040 will be violated immediately upon establishment of the land use. “
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Screening Level ToolsScreening Level Tools
Mn/DOT look-up tables (for lower volume roadways)
TNM look-up software “Flat Earth” assumptions (usually worst case
scenario) “Rules of thumb”
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Mn/DOT Look-up TablesMn/DOT Look-up Tables60 MPH 2500 auto
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60
65
70
75
80
85
0 100 200 300 400 500 600 700
Feet
0 % trucks
5 % trucks
10% trucks
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TNM 2.5 Look-up SoftwareTNM 2.5 Look-up Software
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TNM 2.5 Look-up Software TNM 2.5 Look-up Software ResultsResults
(Note: Results are LEQ only)(Note: Results are LEQ only)
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Mn/DOT 3PC 2D Reverse ToolMn/DOT 3PC 2D Reverse Tool
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Mn/DOT 3PC 3D Reverse ToolMn/DOT 3PC 3D Reverse Tool
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An example of what you don’t An example of what you don’t want to see!want to see!
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Other ResourcesOther Resources
www.pca.state.mn.us/programs/pubs/noise.pdf wwwcf.fhwa.dot.gov/environment/noise/ wwwcf.fhwa.dot.gov/environment/noise/table.htm
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Contact InformationContact Information
Mel Roseen 651-366-5808
Peter Wasko 651-234-7681
Anne Claflin 651-757-2277
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Questions?Questions?
