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Arden Hills 55+ Senior Housing Complex Traffic Noise Assessment David Braslau Associates, Inc. Page 21 5.0 SUMMARY OF FINDINGS Traffic noise levels were monitored during the PM Peak period (4-5 pm) on Wednesday, September 4, 2024 and during the AM “peak nighttime” period from 6-7 am on Thursday, September 5, 2024. Monitor locations are shown on Figure 2.1 During the monitoring PM monitoring period on TH 10 considerable variations in traffic speed occurred due to the interchanges of Hwy 10 with Interstate 35 to the northwest and Interstate 494 to the southeast. However, for purpose of modeling free-flow noise, an assumed free flowing traffic sound level of 74 dBA at the monitor has been assumed for calibrating the noise prediction model for the PM period. Traffic noise levels along TH 96 appeared to flow more smoothly without significant changes in speed. The MinnNoise computer model has been used to estimate nighttime (6-7 AM) and daytime (4-5 PM) sound levels at selected receptors sites distributed around the proposed building using traffic count data from the MnDOT Traffic Mapping Application and directional and hourly traffic volumes from Automatic Traffic Recorder 10919 located on Hwy 10 north of the project. Vehicle type percentages have been based on similar studies in the Twin Cities Metropolitan Area. Correlation between predicted values on TH 96 assuming a speed of 55 mph were close to monitored values but on Hwy 10, a speed of 65 mph was needed for good correlation. Predicted daytime levels were mostly below standards but nighttime (6-7 am) levels were exceeded at all receptor sites on the building. Therefore, exceptions to the noise rules are needed to ensure compliance with the standards. At least STC 28 will be needed for all facades but those with glazing would need up to 30 STC glazing to provide the needed 30 dBA reduction in the noise rule. The final section of the study addresses potential increases in traffic noise levels for homes to the southwest across TH 10 due to reflections off the new building. Help from Bowlby Associates, who is the consultant to the FHWA traffic on noise models, was needed to run the newest model (TNM 3.2) that can address reflections off buildings. Results of the analysis show increases from zero to well below 1 dBA which would not be easily detectable. y:\jobs\2024jobs\224009\report\arden-hills-apartments traffic-noise-assessment.doc