AASHTO Noise Working Group Sound Bites


  • Caltrans spent the first half of 2020 examining ways to implement NCHRP OBSI and beamforming research results for more accurate noise modeling. The slow pace of TNM development and its’ inaccuracy for detailed modelling is driving this effort.  Two different approaches were explored, using either TNM 2.5 or the much more advanced SoundPLAN software. This effort included creating a custom software patch, by inhouse SoundPLAN programmers, for the SoundPLAN portion of the analysis.  Some of this exploratory work will be submitted for potential presentation for TRB 2021.


  • Colorado’s draft noise guidance is currently under review by FHWA HQ.


  • Idaho Transportation Department (ITD) is in the process of revising its 2011 noise policy.  Among other changes, this new policy incorporates the use of FHWA Low Volume Road Tool.


  • Illinois DOT is currently in the process of streamlining and expediting their approval process of alternative noise barriers.


  • Iowa is working on a tool to predict noise barrier costs into the future utilizing buffering within a geographic information system, based on residential lot density, residential distance from the highway, and traffic volumes.


  • Kentucky KYTC and FHWA have updated the KYTC Noise Policy.  The new policy went into effect July 1, 2020.


  • Elton Holloway, Mississippi DOT’s resident expert on all things noise and air quality related, has retired after an incredible 45 years of service.


  • Missouri, despite funding slowdowns, continues to have many Type I projects currently going through studies.  Additionally, Missouri is producing an informational video for public consumption.  The video is basically about our noise process with some education on the fundamentals of highway traffic noise.  We intend to use it at public meetings and on MoDOT websites for educational purposes.


  • The Reno Spaghetti Bowl project is underway.  The first phase will include reconstruction of existing sound walls and the placement of visual screening walls from the Truckee River south to Mill Street as part of the noise mitigation and environmental justice commitments.


  • Ohio is kicking off a Vinyl fence noise wall research project in January 2021. The project involves constructing two 8’ tall vinyl fences at two different locations and testing them for noise reductions and comparing the reductions to nearby concrete noise walls.
  • Ohio’s Noise Model To Monitor Case Study research is on-going.  Preconstruction readings were completed.  Modeling is on-going.  Post construction readings are the next steps.  The research will compare modeled results to measured results.
  • Ohio awarded a noise wall maintenance project in Canton Ohio involving resealing concrete and aluminum panels and patching sound absorptive material.
  • Ohio will be awarding a Type II noise wall project in Toledo in September.  The project involves constructing 2.3 miles of noise wall consisting of 180,000 SF for communities that predate the freeway.
  • Ohio is conducting research regarding Air Quality Effects From Noise Walls And Vegetated Noise Walls.  A report will be completed by end of 2020.
  • Ohio is initiating a small scale research project regarding the Shielding Effects Of Low-Height Walls/Safety Barriers On Heavy Truck Noise.

South Dakota

  • Long-time noise expert, Alice Whitebird, retired in June.  SDDOT finished updating a draft of state noise guidance.  It is being reviewed by our administration then onto FHWA.  This will be SDDOT’s first update since 2011.  SDDOT has one current noise study ongoing with feasible/reasonable criteria met at one location.  SDDOT is going through the public involvement process and will begin balloting soon.


  • Texas has many noise barriers coming down the pipeline in El Paso, Dallas, Fort Worth, Austin, San Antonio, and Houston.   Texas also has some longitudinal tining projects and some with porosity free concrete (PFC).