Traffic Noise Impact Analyses Using a Screening

Methodology: Oregon DOT Experiences

• Presented by: Carole Newvine/Noise Specialist

Oregon Department of Transportation

• Presented at: Transportation Research Board ADC40 Transportation-Related Noise and Vibration 2013 Summer Meeting - Santa Fe New Mexico

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Outline

• OR DOT previous screening methodology

• New screening methodology

• Project experiences using screening – Local Gov’t – suburban setting

– Rural setting

– Protected forest land

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Previous Screening Methodology

prior to 23 CFR 772 update (2010)

Assumptions Receptor Distance: 15 meters from roadway CL Site Characteristics: Hard site, infinite flat roadway, no shielding Vehicle Speeds: 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 km/hr Traffic Characteristics: Peak Hour Traffic Volume (PHT) = 21% of ADT volume Truck Volume = 30% of PHT Volume (27% Heavy Trucks, 3% Medium Trucks) Study Year: 2015

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Previous Screening Methodology

prior to 23 CFR 772 update (2010)

Year Speed ADT 2015 30 km/hr 950

40 km/hr 600 50 km/hr 450 60 km/hr 300 70 km/hr 250 80 km/hr 200 90 km/hr 150 100 km/hr 140

110 km/hr 130 120 km/hr 110

Traffic volumes, speeds below would result in predicted noise levels of Leq 64 dBA at 15 meters (50 ft) from centerline.

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2013 Problem/Solution

• Oregon’s Type I projects in rural areas – project delivery impacted

• No provisions in Federal rule for programmatic streamlining

• Some states already had approval for screening methodologies

- Idaho

- Washington State

- Virginia

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ODOT Screening Methodology for Traffic Noise Impacts – March 2013

Applicability:

Type I projects where noise impacts are not anticipated or when there are impacts but no feasible abatement

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ODOT Screening Methodology – Highlights:

• Oregon’s screening methodology – mirrors WA, ID, VA methods

• TNM to estimate existing, design year traffic noise levels at selected distances from the roadway centerline – out to 1500 ft.

• Conservative results: assumes worst case conditions not actual roadway design or topography

• Technical report required

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ODOT Screening Methodology – Highlights Continued:

• Validation of the straight line model is not required

• Traffic data, vehicle speeds, actual receptor distances from the roadway for Build condition for NAC determination

• Compare Existing to Build to determine substantial increase impacts

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Complex Modeling Straight-line Modeling

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ODOT Screening Methodology Post Modeling

• If abatement appears feasible - detailed analysis required

• No abatement feasible (e.g., driveway access), a detailed noise analysis (full TNM modeling) is not required

• Noise monitoring may be required

• 23 CFR 772 requirements must still be met

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ODOT Screening Analysis for Traffic Noise Impacts – March 2013

Advantages: – Can be done in-house – Saves budget – Can be performed earlier in the project development cycle -

only limited design information needed

Disadvantages: – Limited use – conservative results – Can’t be used for analysis of alternatives – Inappropriate use

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Local Gov’t – Suburban Setting Freeman Road: Central Point

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Local Gov’t – Suburban Setting Freeman Road: Central Point

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Local Gov’t – Suburban Setting Freeman Road: Central Point

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Rural Setting

OR86: Baker County

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Rural Setting

OR86: Baker County

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Rural Setting

OR86: Baker County

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Protected Forest Land US26: Mt Hood Safety Project

Protected Forest Land US26: Mt Hood Safety Project

Critical Viewpoint:

Laurel Hill. Existing Condition

Laurel Hill. Proposed Condition

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Protected Forest Land US26: Mt Hood Safety Project

Critical Viewpoint:

Mirror Lake. Existing Condition

Mirror Lake. Proposed Condition

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Protected Forest Land US26: Mt Hood Safety Project

Mirror Lake Trailhead (continued)

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Protected Forest Land US26: Mt Hood Safety Project

Critical Viewpoint: The Pioneer Bridle Trail at MP 51.30

The Pioneer Bridle Trail at MP 50.90

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Protected Forest Land US26: Mt Hood Safety Project

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Critical Viewpoint: Map Curve.

Suburban setting: Impacts with accessibility issues Rural setting: No impacts

USFS lands, 4(f): Impacts; access issues, Federal and County viewshed restrictions; exceeds cost criteria

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Summary: Type I Projects – Screening Methodology

Contact Information

Carole Newvine/ Noise Program Coordinator 503-986-3447 carole.newvine@odot.state.or.us

Natalie Liljenwall/Air and Noise Engineer 503-986-3456 natalie.liljenwall@odot.state.or.us

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