NCHRP 25-25, TASK 106 HIGHWAY NOISE AND HISTORIC PROPERTIES: A NATIONAL REVIEW OF EFFECTS AND MITIGATION PRACTICES © Google 2018, 2019

NCHRP 25-25, Task 106 The project was guided by a technical working group that included: Antony Opperman – Virginia Department of Transportation (chair) Lisa Schoch – Colorado Department of Transportation Erica Schneider – Ohio Department of Transportation Ray Umsheid – Texas Department of Transportation Sarah Stokely – Advisory Council on Historic Preservation David Clarke – Federal Highway Administration (Liaison) The project was managed by Ann Hartell, NCHRP Senior Program Officer.

NCHRP 25-25, Task 106 Project Understanding and Objectives Section 106 consultation concerning noise effects on historic properties is less common. Assist DOTs in establishing standard practices regarding the long-term effects of highway noise on historic properties. Present effective mitigation practices for such noise impacts. © Google 2018, 2019

NCHRP 25-25, Task 106 Research Methods Annotated Bibliography Little specific information relative to the issue of highway noise. The concept of sound as a contributing element of a historic site is not well studied. Most research is directed to vibration or aircraft noise, not highway noise. Stakeholder Survey Four-question screening survey that solicited experience with highway noise and historic structures issues. Sent to several hundred email addresses. 96 responses. © Google 2018, 2019

NCHRP 25-25 Task 106 Survey Results A total of 96 survey responses were received: 42 responses from state DOTs, representing 28 DOTs. 10 responses from SHPOs. 1 response from another state agency. 9 responses from 5 Federal agencies. 33 responses from the consultant community. 1 response from a non-profit organization. The responses from state agencies (DOTs, SHPOs, and the one state agency) represented a total of 31 states. Three SHPOs responded from states where no DOT responded. There were a combined total of 62 state and federal agency responses. © Paul Graham

NCHRP 25-25 Task 106 Survey Results Of the 96 responses: 61 respondents had experience with highway traffic noise analysis or traffic noise mitigation at historic sites or in historic districts. 48 percent reported a set policy for determining adverse auditory effects from traffic noise. 18 percent of the DOTs reported having a policy that specifically addresses adverse auditory effects to historic properties. © Paul Graham

NCHRP 25-25, Task 106 Interviews Screening survey was used to identify those with the most highway noise and historic structure experience, including state officials and consultants. Experts identified for further in-depth interviews through answers to preliminary survey. Those that answered positively to all four survey questions were contacted with a telephone interview request. ms consultants inc.

NCHRP 25-25, Task 106 Synthesis and Technical Report Interviewing Agencies and Organizations 15 experts identified. 11 interviewed by phone: 3 of whom also submitted written responses to questions. 25 detailed questions asked during interviews. Case Studies solicited Selected based on recommendations by panel, other experts. 7 case studies in 7 states. In only one case was noise a determining factor. . © Google 2018, 2019

NCHRP 25-25 Task 106 Findings   There is a general lack of experience with addressing highway noise impacts to historic properties, but state DOT and SHPO personnel are very interested in having information on how the topic has been successfully resolved elsewhere. Less than 20 percent of agencies, organizations, or companies surveyed have a set policy that specifically addresses adverse auditory effects to historic properties or appropriate mitigation at historic sites or within historic districts. The auditory environment (soundscape) is not regularly considered in the NRHP determination process. Addressing highway noise effects to historic properties is almost always a collaborative effort between the traffic noise and historic resource specialists within state DOTs. FHWA 23 CFR 772, Noise Abatement Criteria (NAC) is frequently used as a first step to determine adverse auditory effects at historic sites or within historic districts.

NCHRP 25-25 Task 106 Findings, cont. Findings continued No Adverse Effect findings occur frequently because traffic noise does not generally alter the characteristics of a resource that make it eligible for the NRHP. Non-auditory solutions, such as landscaping, have been successfully used to resolve auditory adverse effects at historic sites or within historic districts.   Context sensitive aesthetic treatments of noise walls, such as brick facings, have been successfully used to avoid a potentially adverse visual effect at historic sites or within historic districts. With the exception of one case study, noise was never the issue that prevented a project from moving forward in any of the case studied. ms consultants inc.

Study Project Team: Paul Graham, Louis Berger U.S., Inc. Dr. Steven Bedford, Louis Berger U.S., Inc. Karel Cubick, ms consultants, inc. Camilla Deiber, Louis Berger U.S., Inc.

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