2. PROGRESS ON THE 2004 ROADMAP

The 2004 Workshop to develop a Roadmap to Quieter Highways was sponsored by FHWA and hosted by the Institute for Safe, Quiet and Durable Highways at Purdue University. It was held from September 14-16, 2004, on the campus of Purdue University. The workshop was attended by 46 participants.

The action plan developed at the first workshop included a near term component, the so-called "right turn out of the driveway" and a longer term component, the so-called "cross country voyage".

The near term component consisted of four initiatives:

• Clearinghouse: Establish a web-based clearinghouse to clarify federal policy, to provide references to standards and provisional standards for tire/pavement noise measurement, and to collect and distribute data about tire/pavement noise measurements to all of the stakeholders.
• Measurements: Establish an Expert Task Group (ETG) on Tire/Pavement Noise Measurement to:
  • Develop Provisional Standards for consideration by AASHTO.
  • Coordinate international and U.S practitioners to advance measurement methods.
  • Coordinate international and U.S practitioners to establish the correlation between various types of measurements.
  • Contribute data to the FHWA clearinghouse.
  • Promote implementation of the Provisional Standards by practitioners.
  • Evaluate and refine the Provisional Standards to facilitate adoption as Standards.
• Quieter Pavement Alternatives: Mobilize state and federal resources, along with private sector contributions, to work to optimize several quieter pavement designs that are currently available:
  • diamond grinding for PCC pavements and
  • mix designs for porous asphaltic friction courses.

  Monitor case studies for noise, friction, and pavement condition to detect changes over time.

• Education: Develop a training course or workshop with the objective of raising awareness of tire/pavement noise fundamentals to the pavement community and the noise/environmental community.

The longer term component of the plan consisted of the following initiatives.

• Measurements: Continue the work of the proposed Expert Task Group on Tire/Pavement Noise Measurement to ensure a final objective where all data collected on tire/pavement noise and traffic noise in the U.S. is directly comparable
  • Complete standardization of measurement methods for wayside and nearfield (source) measurement and for pavement acoustical properties
  • Correlate wayside and source measurements and develop methods to relate tire/pavement source measurements, pavement acoustical characteristics and wayside measurements
  • Develop calibration and certification pavements (perhaps at test tracks or test sections in each region) to serve as references for practitioners
• Research Noise/Safety/Durability/Cost: Examine the relationship of texture and pavement elasticity to noise, friction, and ride. This effort should be an integrated program of fundamental, laboratory-based work, and test-site-based work. Investigations should include but not be limited to the following:
  • Exposed aggregate concrete
  • Thin gap-graded asphalt overlays
  • Novel texturing methods such as dimpling
  • Porous concrete
  • Double layer porous asphalt

  As the relationships between pavement characteristics and functional performance are better understood, it is expected that other novel pavement concepts will evolve.

• Cost/Benefit: Fund research work to examine the true costs and benefits of noise treatments, as well as safety, durability, and other performance aspects of pavement.
• Guidelines: Based on research results and field studies, FHWA/AASHTO should develop Guidelines for ride, friction, and noise. Individual states would use these Guidelines to develop project specific performance targets.
• Monitoring: Using measurement standards developed by the Expert Task Group on Tire/Pavement Noise Measurement, State DOT's should specify and monitor pavement noise (both as-constructed and in-service). For in-service monitoring, states should establish thresholds for (1) reactive maintenance (2) replacement-reconstruction.
• Accelerated Testing: A panel of pavement and noise experts should develop methods for accelerated testing for acoustical performance, based on existing methods for accelerated testing of pavements.
• Education: Material should be developed and distributed for inclusion in an academic course of study to teach students the concepts of designing quieter pavement. Variations of this curriculum should be offered in continuing education format (e.g., short courses, DVD learning materials) to practicing design engineers.

The stated ultimate goal developed at the first Workshop to develop a Roadmap for Quieter Pavement was a reliable design specification for pavements that are safe, durable, and cost competitive and that are substantially quieter than existing pavement over the entire design life. When this design goal is achieved, policy changes may permit the use of quiet pavement as an alternative for noise mitigation to protect the public. Policy changes may also include a methodology that utilizes pavement characteristics in noise predictions.