Quieter Pavements

Randell H. IwasakiExecutive Director

Asphalt Pavement Conference

CalAPA Executive Director Russell Snyder (right) meets with new Assembly Speaker Toni Atkins in 2014.

About the Contra Costa Transportation Authority

What does this really mean? Responsible for implementing your

vision for transportation in your community

Fund local improvements such as the Caldecott Tunnel Fourth Bore, Highway 4 improvements and programs such as 511 Contra Costa for transit information.

Create partnerships among regional agencies (Caltrans, MTC, the County) to deliver transportation projects and programs on-time and on-budget.

Manages funds generated by the half-cent transportation sales tax enacted in 1988 and renewed in 2004 by voters

• Carries out the voter-approved Measure J expenditure plan

• Serves as Contra Costa’s Congestion Management Agency & administers county’s Congestion Management Program

More info at: www.ccta.net

Keeping Contra Costa Moving byDelivering projects that ease

traffic congestion

Caldecott Tunnel

Route 4 East

E-BART

Real-time carpooling with Car.ma

I-680 Carpool Lane

completion

Express Lanes

Keeping Contra Costa MovingDelivering programs that provide alternative

transportation options

Transportation for Livable Communities

Pedestrian and Bicycle access improvements

Safe Routes to Schools

511 Contra Costa for transit information

Keeping Contra Costa MovingDelivering projects that create a smarter transportation system

Interstate 80

Integrated Corridor Management (ICM) project Adaptive ramp metering;

Incident management;

Information to motorists regarding transit and traffic travel time and conditions;

Improvements along San Pablo and other arterials; and

System Integration

Keeping Contra Costa MovingDelivering projects that create a smarter transportation system

Traffic Light Synchronization

Keeping Contra Costa MovingDelivering projects that support our local communities

18% of all funding is automatically

distributed to cities

for maintenance of local streets and

roads

Noise Issues Are Not New

8000 BC Worlds First Major Town-Jericho

5000 BC Wheel Invented

4000 BC Mesopotamia

800 BC Iron Tires Introduced

44 BC First Noise Regulation

1869 London Report

1870s Use of Wood Blocks

1888 Pneumatic Tire Invented

What Can Be Done to Mitigate Pavement Noise?

Distance

Obstructions

Noise Walls

Earth Berms

Trees/ Shrubs

Control at the Source with

Pavement Surface

WallsEffective only for those in line-of-sight.

Does not reduce

noise at source.

Controlled At the Source

Stone Paved Streets

1897 Survey of 122 Cities with Paved Streets and Pop. > 10,000

Paving Type Paved Length (km)

Asphalt 230

Granite Setts 1,920

Wood Block 1,220

Brick Block 1,160

Rock (Macadam?) 910

Total 5,440

Additional Surface Types

Hot Mix Sheet Asphalt

Doubling Traffic adds 3dBA

How Do We Quantify Noise

Ways of Measuring Sound

Wayside (Far Field)

Close Proximity (Near Field)

Noise Intensity (Near Field)

Caltrans

Noise Intensity

How Did We Get Here? The Technical Journey Begins!

The Technical Journey?

Development of Improved OGFC for Use in Snow Country (1970s-80s)

Improved OGFC Used to Resist Reflective Cracking (1980s-90s)

Improved OGFC Used as PCCP Overlay (1980s-2000s)

Benefit For Smoothness (1990s)

Benefit for Noise (1990s-2000s)

“Pavement / tire noise

has been studied for

well over 30 years and

several large

databases have been

compiled in the last

decade.

NCHRP SYNTHESIS 268

“In general, when dense-

graded asphalt and PCC

pavements are compared,

the dense-graded is quieter

by 2 to 3 dB(A)”

A 3dB(A) reduction corresponds to:

- doubling the distance

- reducing traffic volume by 50%

- reducing traffic speed by 25%

CONCLUSIONS

“Open-graded asphalt shows

the greatest potential for

noise reduction for pass-by

noise. Reduction when

compared to dense-graded

asphalt ranged from 1 to 9

dB(A).”

A 9dB(A) reduction corresponds to:

- a reduction in traffic noise by

almost 50%!

CONCLUSIONS

(1) Network Level Evaluation of ARFC Surfaces

AR_ACFC Noise Levels Versus Pavement Age

y = 0.5453x + 93.279

R2 = 0.5805

93

94

95

96

97

98

99

100

101

102

0 2 4 6 8 10 12 14

Pavement Age

CP

X N

ois

e L

evels

dB

A

(2) Evaluation of PCCP Tining Methods

Longitudinal Uniform

TransverseRandom

Transverse

(3) Comparison of Different Mixes

Wearing Course

Surface Type

CPX Noise Level

(dBA)

SMA 95.9

AR-ACFC 95.0

PEM 96.0

Lessons Learned To Date

Comparison of Various Surface Types

Comparison of Measurement Systems

Environmental Effects

We Have Only Just Begun the JOURNEY!

Mix Design Procedures

Lessons Learned From Europe

Double-layer porous asphalt pavement on the A28 in the Netherlands

QUIET PAVEMENT SYSTEMSFHWA/AASHTO INTERNATIONAL TECHNOLOGY SCAN

Draft Executive Summary Report – 2 June 2004Scan Co-Chairs

David Gibbs, P.E., FHWA Utah Division

Randell (Randy) Iwasaki, P.E., California Department of Transportation

In Summary

Surface Type Does Matter-Noise Should be Controlled at the Source

Noise Should be Managed Just Like Friction, Roughness, Rutting, and Cracking

People Do Care How They Live - It’s a Quality of Life Issue!!!

CCTA CV/AV Testbed

Thank you!

CCTA.net

ContraCostaTransportationAuthority

@riwasaki2