 IMPACTS:
The peak hour noise levels presented in the Final EIS indicate that there is little acoustical difference between the various proposed alternatives considered in the EIS.
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The EIS shows that there will be slight increase in noise levels for a majority of the corridor under all alternatives, including the no-build. Under the Selected Alternative, throughout the corridor noise levels immediately abutting the Evangeline Thruway, including noise levels at the St. Genevieve Church and School within the Sterling Grove Historic District, will decrease because the ground level Thruway will be relocated farther away from the existing church and school and because through traffic will use the I-49 Connector freeway (which will remove traffic from the local street). Although these noise reductions will be noticeable, the resulting levels will still exceed the LaDOTD’s Noise Abatement Criteria (NAC) and by definition the residences, schools and churches immediately abutting the Evangeline Thruway would still experience an acoustical impact. Sound walls and other noise reduction measures were considered but determined not practical and feasible according to the LaDOTD’s criteria.
Within the Sterling Grove Historic District the second and third tier of homes paralleling the Evangeline Thruway would be exposed to less noise than the St. Genevieve Church and School. These homes would most likely experience an increase from existing noise levels (because the ground level buffer provided by the existing buildings and vegetation would be less effective for an elevated noise source), but the increase would probably not be great enough to meet the LaDOTD’s definition of impact.
Interior noise projections and evaluations have been done for the two schools, LeRosen and St. Genevieve Elementary Schools, which are in close proximity to the Selected Alternative. It has been estimated that interior noise levels at LeRosen will increase compared to existing conditions, while interior noise levels at St. Genevieve will decrease compared to existing conditions. These interior noise level projections exceed standards set forth by LaDOTD; therefore noise reduction measures have been identified.
Construction noise is also expected to occur with the proposed project. The major construction elements of this project are expected to be earth removal, hauling, grading, paving, and bridge construction. Construction noise is expected to have temporary impacts upon the residences, churches, schools, and businesses that are located immediately adjacent to the project corridor.
COMMITMENT:
Traffic Noise
Based on the studies completed for the EIS, none of the noise barriers analyzed meet the LaDOTD’s definition of reasonableness and feasibility. If it subsequently develops during final design that conditions have substantially changed, abatement measures would be re-evaluated by LaDOTD. A final decision on the reasonableness and feasibility of noise mitigation will be made by LaDOTD and FHWA upon completion of the project design and the public involvement processes.
Construction Noise
LaDOTD’s project engineer will monitor the following items during the construction period. Construction equipment powered by gasoline or diesel fueled internal combustion engines will be properly muffled and all motor panels will be closed in order to minimize the noise impacts to nearby areas. Shielding of stationary noise sources with temporary noise barriers will be considered at all times. Section 107.15 of the Louisiana Standard Specifications for Roads and Bridges and the FHWA Technical Advisory T 6160 2 dated March 13, 1984, will be referenced for further details on the sources and abatement of construction noise.
Construction Noise Near Churches
To minimize construction noise impacts to the churches along the corridor, at the beginning of project construction, the LaDOTD’s project engineer will contact the churches immediately adjacent to the proposed project to obtain their schedules of regular services as well as the anticipated dates and schedules of Holy Day observances. Construction operations immediately adjacent to churches will cease during weekend services (Saturday and Sunday) or Holy Day observances. In addition, the LaDOTD will coordinate with churches along the corridor to the extent practicable for unscheduled services such as funerals. It is anticipated that it will be necessary for construction work to take place on Saturday and Sunday in the vicinity of churches in order to minimize disruption to local traffic and businesses during the Monday through Friday workweek.
MITIGATION:
Traffic Noise
Walls were considered to diminish the noise levels; however, analysis has shown that none of the areas within the corridor met the LaDOTD’s criteria for noise barriers. Noise reduction measures within the corridor being considered are to be funded by local and/or private agencies and organizations. The use by the LCG of a Noise Impact Overlay Zone is one potential opportunity, as it would subject land within the zone not only to common regulations for that zone, but also the developed terms for the overlay zone. Physical methods being considered by LCG for sound abatement include acoustical site planning, architectural design and construction, as well as the construction of noise barriers. Acoustic site planning includes distance barriers, noise-compatible use (parking, open space and commercial) and buildings as barriers or buildings that would not face the highway. Architectural design includes concerns such as building height, room arrangement and window size, number and placement. The LCG will be responsible for any noise mitigation measures for the I-49 Connector project, except as noted in the following paragraph, notwithstanding the re-evaluation commitment made for traffic noise.
Interior Noise
Both the St Genevieve and LeRosen Elementary school campuses are expected to experience noise levels higher than the impact threshold. Based on the data available at the time of this study and the results of this study, it is noted that acoustical windows installed in the LeRosen Computer Laboratory and the St. Genevieve Library would serve to mitigate noise due to the I-49 Connector project. This action should be taken prior to construction of the I-49 Connector so that benefits would accrue both for the construction period and day to day freeway operations thereafter. The LaDOTD could make a direct mitigation payment to the schools based on the estimated costs of the windows as discussed above, with the concurrence of the FHWA and the written agreement of the respective school administrations to implement the installations.
STATUS:
See table below.
NOISE
| Commitment/Mitigation Tasks | When to Occur | Status | Date Completed | Links to Relevant Resources |
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| Re-evaluation of noise walls by LaDOTD during final design, if conditions have substantially changed | F | No Activity | | N/A |
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| Possible provision of noise walls or other noise control measure by the LCG | P,F,C | No Activity | | CSS |
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| Special construction measures to control noise near churches | C | No Activity | | N/A |
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| Acoustical windows installed by LaDOTD at LeRosen Computer Laboratory and St. Genevieve Library (or equivalent direct payment) | C | No Activity | | N/A |
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| *Note: P = Preliminary Design Phase, F = Final Design Phase, C = Construction Phase |
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