1 Mn/DOT’s Noise Criteria and Modeling Presenters: Peter Wasko, Mn/DOT Metro District Mel Roseen, Mn/DOT Environmental Services Anne Claflin, Minnesota Pollution Control Agency FHWAMn/DOT MPCA

2 Regulatory Agencies Noise 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

3 Regulatory 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.

4 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

5 23 C.F.R. 772 Mn/DOT Noise Policy for Type I and Type II Federal-aid Projects as per 23 CFR 772 Purpose: “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).”

6 Federal Noise Abatement Criteria Residential: – L 10 of 70 dBA both day and night Commercial: – L 10 of 75 dBA both day and night L 10 is the sound level that would be exceeded 10% of the time ie: 6 minutes of a 1 hour monitoring period

7 Minnesota 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 , empowers the MPCA to enforce the limits defined in the state rule.

8 Minnesota Noise Rules Noise Area Classifications (NAC) NAC-1 Residential NAC-2 Business NAC-3 Industrial

9 Minnesota Noise Rules Receiver Based Noise Limits (dBA) Daytime Nighttime NAC L50 L10 L50 L 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.

10 1 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?

11 Common question is.. What roads are exempted under ?

12 Exemptions From State Standards “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.”

13 Exemptions From State Standards “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.”

14 Exempt from State Noise Standards

15 Not Exempt from State Noise Standards

16 Possibly Exempt from State Noise Standards

17 How do we determine when and how to mitigate noise?

18 Type 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."

19 Type 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.”

20 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.

21 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.

22 Partial MnNoise Input File noise model for peak traffic TH north bound 'CARS' 'MT' 'HT' 'L'/ 'nb1' 'nb2' 'nb3' 'nb4' 'nb5' 'nb6' 'nb7' 'nb8' 'nb9'

23 FHWA 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.

24 What is necessary to model 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)

25 What is helpful in modeling noise in a given area (cont) # of homes/residencies in a given area Shielding effects of obstacles (natural berms, buildings, vegetation, etc.) Ground surface effects (hard or soft ground)

26 Background Traffic Noise Measurements Why are measurements needed? When and how to conduct them Duration # of repetitions Weather Traffic data collection and documentation

27 Modeled Receiver Location “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).

28 A C E D B F HI G Possible Receiver Placement Right of Way 28

29 MIN 20 Feet 5 FT 29 Receiver Height Placement Receiver R.O.W.

30 How does Mn/DOT determine if a noise wall is feasible and reasonable?

31 Barrier feasibility and reasonability concerns: Does Mn/DOT have the required right of way to construct the wall? Safety concerns such as sight distances and clear zones.

32 Buried utilities or utility relocation needs?

33 Would hydraulics or drainage features on the right of way be impacted?

34 Are there concerns with soil types or wetland areas in the proposed project area? 34

35 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 Considerations

36 Example of City Resolution

37 Mailer example

38 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 Criteria

39 Common Noise Wall Materials

40 Earth Berm

41 Wood post/wood plank

42 Concrete post/wood plank

43 Concrete

44 Glue Laminated wood

45 Pavement 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.

46 Why Not Plant Trees Instead 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

47 How Effective Are Noise 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).

48 Barrier Attenuation and Path Length Difference AB C Path length difference (PLD) = (A + B) - C Barrier attenuation increases as the PLD increases

49 How Effective Are Noise 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.

50 Intervening Ground Example: Depressed Roadway

51 Possible Noise Barrier Placement Clear Zone Line of sight Right of Way

52 Possible Noise Barrier Placement Clear Zone Line of sight Right of Way

53 Effect of Partial Barrier -10 dBA -3 dBA 0 dBA Exposed to half the traffic = -3 dBA Wall 51

54 Barrier End Points (using the 4D rule) 4D D D Noise Sensitive Receivers > 80° 52

55 Barrier Overlaps 4D Overlap gap between barriers D 53

56 Barrier Location Example Source Close to Source (more effective) Half way between (less effective) Close to receiver (more effective) Receiver Source Receiver Source Receiver 54

57 Line 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 55

58 How Much Do Noise Walls 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

59 Does a barrier on one side 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

60 Construction Noise

61 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 Model Communication with residents is the key!

62 FHWA Roadway Construction Model 60

63 Land use planning Minnesota Rule states: “ No person may violate the standards established in part , unless exempted by Minnesota Statutes, section , 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 will be violated immediately upon establishment of the land use. “

64 Screening 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”

65 Mn/DOT Look-up Tables

66 TNM 2.5 Look-up Software

67 TNM 2.5 Look-up Software Results (Note: Results are LEQ only)

68 Mn/DOT 3PC 2D Reverse Tool

69 Mn/DOT 3PC 3D Reverse Tool

70 An example of what you don’t want to see!

71 Other Resources wwwcf.fhwa.dot.gov/environment/noise/ wwwcf.fhwa.dot.gov/environment/noise/table.htm

72 Contact Information Mel Roseen Peter Wasko Anne Claflin

73 Questions?