3. RECENT PROGRESS

Much of the near term component and part of the long term component of the original roadmap have been accomplished in the 18 months time period between the first and second workshops. Specifically

• Quieter Pavement Alternatives:
  • The FHWA Office of Pavement Technology has funded development of quiet pavement technology for both asphalt and Portland Cement Concrete (PCC). For asphalt, FHWA has funded the National Center for Asphalt Technology (NCAT) to test certain variations of current mixes and several innovative surfaces at the NCAT track in order to establish the noise reduction benefit and the long term performance trends. Results of these efforts were reported at the Workshop by Smit. The FHWA has also funded the National Concrete Pavement Technology Center to do lab studies and field evaluations of variations of current technology and innovative PCC surfaces. Results of these efforts were reported at the Workshop by Rasmussen. In these early stage evaluations we are finding clear evidence of what not to do in order to avoid exceptional noisy pavements and are beginning to focus on concepts that consistently produce quieter pavements.
  • A Quiet Pavement Pilot Program (QPPP) was initiated by the Arizona DOT in April 2003 for the Asphalt Rubber Friction Course (ARFC) pavement. The study has found that ARFC significantly reduces perceived noise relative to the preexisting pavement (usually a uniform transversely tined concrete). Measured reductions are typically about 5 dBA in adjacent neighborhoods. Additional monitoring will be done to establish the durability of the noise reduction effect. See the presentation by Dennis.
  • Several states report progress on Quiet Pavement Research Programs (QPR) including California (see Rymer and http://www.dot.ca.gov/hq/env/noise/publications), Colorado (see Mero), Florida (see Berrios), Texas (see Shearer, Seiders, and Trevino), Virginia (see McGhee), and Washington (see Waters and Pierce).
  • The NITE (Noise Intensity Testing in Europe) Project was funded by CALTRANS, AASHTO, and the FHWA and was conducted by Paul Donavan from Illingworth and Rodkin in fall 2004. Measurements were taken on more than 60 pavements in Germany, Netherlands, Belgium and France. In general, both the noise levels and distributions of current technology in Europe and in the U.S. are similar. The only European technologies that are not currently used in the U.S. that performed well in the NITE study were Double Layer Porous Asphalt (DLPA) and ground porous concrete. There is also a tendency in Europe to use smaller aggregate size for quieter pavement within a specific pavement type.
  • NCHRP is funding project 1-44 Measuring Tire-Pavement Noise at the Source to develop a method to measure tire/pavement noise at the source.
  • NCHRP is funding project 8-56 Truck Noise-Source Mapping to do an acoustical imaging study of trucks to determine the rank priority of noise sources on trucks. In addition, CALTRANS has been funding Illingworth and Rodkin to look at tire-pavement noise of truck tires using the OBSI method. (See the presentation by Donavan).
• Measurements: An Expert Task Group (ETG) for Pavement Noise Measurement has been established. It consists of 10 members and 3 technical resources. The short-term objective of the ETG is to develop a draft provisional standard for consideration by the AASHTO Subcommittee on Materials for On-Board Sound Intensity and wayside sound measurement methods. The ETG has developed two draft provisional standards for measuring tire/pavement noise at the source. One of the provisional standards addresses the equipment specification, while the other addresses the measurement method. These provisional standards will be submitted to AASHTO for consideration as AASHTO Provisional Standards. AASHTO provisional standards are considered temporary and are used when the standard is expected to be subject to considerable and rapid change due to such aspects as the implementation of ongoing research and development efforts.
• Education: The first step in a technical education program has been successfully accomplished. The FHWA Office of Pavement Technology has funded the development and presentation of a one day workshop entitled Tire-Pavement Noise 101. The workshop is intended to bridge the gap between noise practitioners and pavement practitioners. Response has been very positive. Sixteen workshops will be complete by mid-July throughout the U.S. (in FL (2), KY, NJ, MN, IA, CA, WA, TX, VA, KS (2), HI, MD, MO) and a contract is anticipated for 15 more workshops.
• Clearinghouse: The FHWA offices of Pavement Technology and Noise have developed a web based Pavement-Related Traffic Noise Clearinghouse. The Clearinghouse at www.pavenoise.us includes web pages for Policy, News, Resources, and Contacts. The Clearinghouse was almost complete at the time of the Workshop and should be online as soon as approvals are complete.

Other notable accomplishments toward the objectives of the first Roadmap relate to longer term objectives and include:

• The Quiet Asphalt 2005 Symposium was held November 1-3, 2005 in Lafayette, IN. The Symposium was sponsored by the Asphalt Pavement Alliance. The Symposium consisted of presentations about current quieter asphalt technology in the U.S. and Europe, fundamental background material on noise and pavements, and discussion of future directions. For a summary of future directions see the presentation by Jones.
• The National Concrete Pavement Technology Center has led an effort to develop a strategic plan for Surface Characteristics (SC) that includes a section on tire/pavement noise reduction for concrete pavements. The plan includes field measurements of current technology and both laboratory and field investigation of innovative technology such as exposed aggregate and porous concrete. For a summary of the SC Roadmap, see the presentation by Wiegand.
• The FHWA Noise Office has issued a new FHWA Policy Memo "Guidance on Quiet Pavement Pilot Programs and Tire/Pavement Noise Research" and is currently revising the FHWA "Highway Traffic Noise Analysis and Abatement: Policy and Guidance".
• Europe and Japan continue to advance the technology of quieter pavement (see the presentations by Sandberg and van Blokland). Significant investment is being made to develop innovative technology. Three efforts are of particular note, the effort to create a durable poro-elastic pavement in Japan, the Innovative Pavements Programs in the Netherlands, and the new EU integrated project called Silence.