The I-65/I-70 North Split Project Team has completed its evaluation of potential noise impacts in the North Split project area based on guidelines outlined in the Indiana Department of Transportation Traffic Noise Analysis Procedure (INDOT Noise Policy).

NOISE REDUCTION FEATURES

The Traffic Noise Model used in the North Split noise analysis predicts a reduction in noise at most locations even if no noise barriers are installed. This modeled reduction in noise levels is primarily the result of the elevation and realignment of proposed roadways and replacement of guardrail with concrete safety barriers. To reduce noise levels further, INDOT is incorporating additional design features that are not recognized in the Traffic Noise Model. These features include:

“Next Generation” Pavement* – This new paving technique is designed specifically to reduce tire noise through the use of longitudinal grooves. Although results vary based on tire manufacturer, existing pavement type and condition, and other factors, recent studies have shown that next generation pavement can reduce tire noise levels by 3 to 5 decibels or more.

Continuous Reinforced Concrete Pavement – This paving technique eliminates the need for transverse joints, which are the cause of rhythmic sound patterns of tires passing over traditional concrete roadways.

Jointless Concrete Bridges – This design eliminates the open joints at the end of bridges, which are the cause of the “banging” sounds typically heard at older bridges such as those currently existing in the project area.

NOISE BARRIERS RECOMMENDED FOR CONSTRUCTION

The following potential noise barriers are recommended for construction:

NB3E : Westbound I-70, along the edge of the north shoulder from Valley Avenue to Commerce Avenue, near the Martindale-Brightwood neighborhood

: Westbound I-70, along the edge of the north shoulder from Valley Avenue to Commerce Avenue, near the Martindale-Brightwood neighborhood NB3W : Westbound I-70, along the edge of the north shoulder from Commerce Avenue to Lewis Street, near the Martindale-Brightwood neighborhood

Factors considered in recommending these noise barriers are as follows:

Survey of Benefited Receptors – In accordance with the INDOT Noise Policy, surveys were sent to obtain the views of benefited receptors (property owners and residents) and a public meeting was held in the adjacent neighborhood to describe the results of the noise analysis and encourage survey response. Social media posts and Listserv emails were sent, and door hangers were hung on doors of benefited receptors to encourage completion of the surveys and attendance at the public meetings. Forty-eight percent (48%) of NB3E benefited receptors responded, with 93% expressing support. Seventy-eight percent (78%) of NB3W benefited receptors responded, with 100% expressing support.

Other Considerations – According to the INDOT Noise Policy, a re-evaluation of the noise analysis will occur during final design. If it is determined that conditions have changed such that noise abatement is not feasible and reasonable, the abatement measures might not be provided.

NOISE BARRIERS NOT RECOMMENDED FOR CONSTRUCTION

The following potential noise barriers are not recommended for construction:

NB4 : Northbound I-65, along the edge of the north shoulder between College Avenue and Alabama Street, near the Old Northside neighborhood

: Northbound I-65, along the edge of the north shoulder between College Avenue and Alabama Street, near the Old Northside neighborhood NB5 : Southbound I-65, along the edge of the south shoulder between College Avenue and Alabama Street, near the Chatham Arch and Saint Joseph neighborhoods

: Southbound I-65, along the edge of the south shoulder between College Avenue and Alabama Street, near the Chatham Arch and Saint Joseph neighborhoods NB7 : Southbound I-65/westbound I-70, along the edge of the west shoulder between 10th Street and Ohio Street near Massachusetts Avenue and the Lockerbie Square neighborhood

Factors considered in recommending these noise barriers not be constructed include:

Survey of Benefited Receptors – In accordance with the INDOT Noise Policy, surveys were sent to obtain the views of benefited receptors (property owners and residents) and public meetings were held in the adjacent neighborhood of each potential noise barrier to describe the results of the noise analysis and encourage survey response. Social media posts and Listserv emails were sent, and door hangers were hung on doors of benefited receptors to encourage completion of the surveys and attendance at the public meetings. Surveys were sent a second time for these three barriers because the percent response rates were under 50%. The responses for each barrier are shown below. NB4 : Surveys were sent in mid-October 2019. The response rate was below 50%, so a second survey was sent to non-responders early in November 2019. After the second survey, a majority (55%) of benefited receptors had responded, with 59% expressing opposition to this barrier. NB5 : Surveys were sent in mid-October 2019. The response rate was below 50%, so a second survey was sent to non-responders early in November 2019. After the second survey, along with four public meetings, social media posts, emails, and door hangers, fewer than half (38%) of benefited receptors had responded, with 74% expressing support for this barrier. NB7 : Surveys were sent in mid-October 2019. The response rate was below 50%, so a second survey was sent to non-responders early in November 2019. After the second survey, along with public meetings, social media posts, emails, and door hangers, fewer than one-quarter (23%) of benefited receptors had responded, with 63% expressing support for this barrier.

Other Considerations – In accordance with the INDOT Noise Policy, which states “the concerns of opinions of the property owner and the unit occupants will be balanced with other considerations in determining whether a barrier is appropriate for a given location,” INDOT considered other reasonableness factors related to changes between existing and future build conditions in evaluating these barriers. These considerations include: Effects to Historic Properties – Six historic districts listed on the National Register of Historic Places (NRHP) are located immediately adjacent to or near the North Split Project area. INDOT, acting on behalf of FHWA, is required to comply with Section 106 of the National Historic Preservation Act of 1966 as amended (Section 106), and its implementing federal regulation, 36 CFR 800. Section 106 and 36 CFR 800 outline a process that requires FHWA and INDOT to evaluate the effects of undertakings on properties that are listed on or eligible for listing on the NRHP. The State Historic Preservation Office provided a letter to INDOT and FHWA, dated November 1, 2019, expressing deep concern about the visual effect of NB4, NB5, and NB7 on the setting of the historic districts near the North Split. The letter described the noise barriers as an additional and severe adverse effect to the character and setting of these resources, greatly amplifying the visual impact of the existing interstate highway intrusion within the historic districts. The letter stated the noise barriers would serve to further isolate historic districts and adjacent structures and strengthen the perceived and actual separation between neighborhoods on either side of the highway. A letter provided by the Administrator for the Indianapolis Historic Preservation Commission on November 8, 2019, stated NB4, NB5, and NB7 would create a severe visual adverse effect by diminishing the feeling, setting, and character of the historic properties and the historic resources within them. Several historic neighborhoods submitted written comments in opposition to NB4, NB5, and NB7: Saint Joseph Historic Neighborhood Association Chatham Arch Neighborhood Association Holy Cross Neighborhood Association Old Northside Neighborhood Association Historic Urban Neighborhoods of Indianapolis Mixed-Use Developments – The INDOT Noise Policy recognizes the potential for conflicts in mixed-use developments, as barriers to protect residences may block line of sight to adjacent businesses. NB5 and NB7 are between the interstate highways and the Indianapolis central business district, which includes a concentration of mixed-use development.



Different views by residential and business receptors were most notable with NB7. The overall survey response rate along NB7 was only 23%, but the survey response rate from businesses was near 50%. Of those businesses that responded, 90% were opposed to the installation of noise barriers.

*American Concrete Pavement Association and International Grooving and Grinding Association, Development and Implementation of the Next Generation Concrete Surface, August 8, 2017, pp 36-37.

See the Traffic Noise Technical Report

See additional information about the noise study and survey