Long‐term Noise Performance ofLong term Noise Performance of OGAC – Results of 10‐year long study

Interstate 80 – East of Davis, California

Dana M. LodicoLodico Acoustics LLC

TRB ADC 40

Transportation‐Related Noise & Vibration Meeting

James A. ReyffIllingworth & Rodkin, Inc

Bruce Rymer

Vibration Meeting

Dayton, OH

July 26‐29, 2009

Bruce RymerCalifornia Department of Transportation

Overview

• Interstate 80, East of Davis, California– Traffic: ~146,000 ADT, ~10% Trucks (2006)– Geometry: six lane divided freeway, no notable grade or cross slope 

– Area:  undeveloped agricultural land

• Timeline– Originally aged DGACOriginally aged DGAC– OGAC overlay placed in 1998– Measurements made 1998‐2008 (ongoing)

• Funded by California Department of Transportation (Caltrans)

Pavements MonitoredOriginal aged DGAC (June 1998)

New DGAC leveling course (July 1998)New DGAC leveling course (July 1998)

OGAC overlay just after application (August 1998) and three times per year (summer winter andand three times per year (summer, winter, and spring) during aging process (1998‐2008)

OGAC OverlayAged DGAC

Measurements

• Continuous Time Integrated Method (CTIM)– Measures traffic and community noise

– Conducted prior to overlay, just after, and 3 times per year (spring, summer, winter) following application

– More than 275 hours of data (> 70 days over 10 years, 1998‐2008)

• On‐Board Sound Intensity (OBSI)– Measures tire‐pavement noise exclusively– Measures tire‐pavement noise exclusively

– Measurements beginning in September 2002

• Traffic volumes, mix, and speed– Free flow traffic conditions only

• Air temperature, wind speed/direction, and humidity

Measurement Locations: CTIM

WB Reference CTIM Location WB Distant CTIM Locations

Reference: Distance: 65‐ft, Height: 10‐ft 

Distant Elevated: Distance: 475 ft Height: 5 ftDistant Elevated: Distance: 475‐ft, Height: 5‐ft 

Distant Ground: Distance: 475‐ft, Height: 15‐ftDistant Ground: Distance: 475 ft, Height: 15 ft

*Presentation focuses on Westbound CTIM and OBSI location results.

Measurement Configuration: OBSI

Single probe configuration Dual probe configurationSingle probe configuration (leading edge)

Dual probe configuration

Goodyear Aquatred 3 Test Tire

Measurement Locations

WB CTIM Locations

Traffic Observation L ti OBSI‐W2

OBSI‐W1

Location

OBSI‐E2OBSI‐E3

OBSI W2

OBSI‐W3

EB CTIM LocationsOBSI‐E1

*Presentation focuses on Westbound CTIM and OBSI location results.

Data AnalysisData Analysis

• Intervals with non‐I80 traffic events removedIntervals with non I80 traffic events removed

• NormalizationFHWA TNM 2 5 d f li ti f CTIM– FHWA TNM 2.5 used for normalization of CTIM

– Model NOT used to predict sound levels

– Traffic spectra not normalized

Measured Levels: CTIM Reference

*Noise levels not normalized for traffic.

Pavement Performance: CTIM Reference

~1 dBA

~7 dBA

~2 dBA

Pavement Performance: OBSI

1/3rd Octave Band Spectra: CTIM ReferenceSummer DataSummer Data

Aged DGAC

1/3rd Octave Band Spectra: OBSISummer DataSummer Data

Pavement Aging: CTIM ReferenceSummer DataSummer Data

Increase ~0.2 dBA per year

Pavement Aging: OBSISummer DataSummer Data

PhysicalIncrease ~0.1 dBA per year (w/o 10-yr data)

Physical deterioration(same as CTIM from 2002 – 2007)

Seasonal Trends: CTIM Reference

Winter 1.3 dBA > summer

Spring 0 4 dBA > summerSpring 0.4 dBA > summer

Seasonal Trends: OBSI

Winter 1.7 dBA > summer

Spring 1.0 dBA > summer

Seasonal Trends: CTIM Reference Spectra

Seasonal Trends: OBSI Spectra

Wind Effects: CTIM Reference(Worst Case Shown)(Worst Case Shown)

Up to 2 dBA range

Wind Effects: CTIM Distant Elevated

Downwind UpwindDownwind Upwind

TNM Predicted Delta

Wind Effects: CTIM Distant Ground

TNM Predicted Delta

Downwind Upwind

ConclusionsConclusions

• New OGAC about 7 dBA below baseline DGACe OG C about d be o base e G C– Equivalent to 8 ft barrier

• OGAC was 4 dBA <TNM 2.5 ‘average’ pavementg p• OGAC maintained performance 

– 2 dBA increase over 10‐yrs

• Winter noise levels 1.3 dBA higher than summer• Wind conditions affected reference CTIM by up y pto 2 dBA and distant CTIM by >10 dBA

• May be appropriate to utilize both CTIM & OBSI