State Route 24 Oakland, CA Pre-NBSSR Noise Study: Responses from the author
Prior to the creation of RockridgeSoundwalls.org, this writer sent an early draft of the critique of the
Pre-NBSSR Noise Study to its author, Steven L. Wolfe, President and Principal Consultant, Wilson, Ihrig and
Associates, Inc. In an e-mail dated April 27, 2011, Mr. Wolfe replied:
"[I] did get a chance to look at what you have written. I have commented about a few items, which may
be mis-leading to the reader. However, overall I don't have problems with what you've said
[emphasis added]. But it should be remembered that the study was basically to see if the general premise
of soundwalls are viable since Caltrans and the City of Oakland have received noise complaints from many
residents in the Rockridge area due to noise from SR24 traffic. Also, we are obligated to undertake the
study in the manner approved by both AACMA and Caltrans. We didn't invent the methodology or the traffic
projections.
A full NBSSR study will undoubtedly be performed prior to implementation of any soundwalls. If the
residents of Rockridge really don't want soundwalls, I'm sure that would fine with Caltrans."
As a result, this writer made a few corrections to the draft critique and submitted it as an article to
The Rockridge News (RN), which declined to publish it. After creating this website, this writer wrote a
letter to the Editor of The RN inviting readers to visit RockridgeSoundwalls.org. That letter was published in the November,
2011 issue of the RN along with this response from Mr. Wolfe:
Reply to "Noise Level Findings in Soundwall Feasibility Study are Flawed" letter
"This letter is to go on the record as far as Wilson, Ihrig & Associates's (WIA) position regarding
soundwalls in the Rockridge area adjacent to SR 24 and on our Pre-NBSSR (Noise Barrier Scope Summary
Report) Study that we completed for Caltrans in 2009. There seems to be confusion by some regarding
the basic purpose and particularly the results of the study. First, WIA has no interest whatsoever
regarding the outcome of such a study. Second, we did not develop the methodology of the study nor
provide input on the accuracy of studies using the methodology prescribed by AACMA or Caltrans. It
should be understood that a Pre-NBSSR study is just a preliminary study to determine if soundwalls have
any merit. Further study is certainly warranted and that is understood or should be understood by all
involved parties. The study basically entailed reviewing previous Caltrans studies from the Caldecott
Tunnel to I-580, obtaining existing noise levels at a number of locations along SR 24, locating affected
receptors, projecting peak hour noise levels to these receptors to determine the potential need for
noise mitigation, estimating soundwall effectiveness (where warranted), estimating preliminary soundwall
costs using Caltrans developed spreadsheets, and preparation of a report presenting the results of the
study. Our understanding is that there are both those who are in favor and those who oppose soundwalls
adjacent to SR 24 in the Rockridge neighborhood. Ultimately, it is the community that will decide if such
soundwalls are actually implemented after a more detailed and accurate study of the existing and future
noise levels in the area is prepared, the technical justification for such walls is demonstrated and
potential funding identified.
We stand by our report prepared in 2009 and encourage careful review of the assumptions and conclusions
with the understanding that this was a very conservative study, to identify all areas where soundwalls
can be justified based on the criteria specified by AACMA and Caltrans.
- Steven L. Wolfe President and Principal Consultant, Wilson, Ihrig and Associates, Inc."
This writer replies to Mr. Wolfe's comments
Ihrig and Associates did follow AACMA's criteria, which Mr. Wolfe describes as "very conservative".
These criteria do not reflect real conditions; instead, they make assumptions that lead to the
conclusion that soundwalls are justified - when actual measurements show that they are not.
Mr. Wolfe did not dispute this. It is fine to say that more study is warranted until you realize
that further study is expensive and would be a substitute for other worthy projects.
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