Santiago Hills II East Orange General Plan Noise Assessment Matthew B. Jones, P.E. Mestre Greve Associates

Noise 101 The Highlights Decibels Noise Metrics Decibel Addition

What the dB? Sound is Air Pressure Fluctuations Unit of Measure: Pascals The Range of Human Hearing is Very Large Pascals to 200 Pascals Ratio of Pressures Describe Loudness Changes Better Than Differences Decibels are Logarithm of Ratio dB = 10 log (p 2 /p r 2 )

dB - It’s a Good Thing Compresses Range of Sound Levels to a More Useful Scale (0 dB to 135 dB) Correlates Well With Perception 10 dB Perceived as a Doubling of Level 1 dB JND in Laboratory 3 dB Barely Discernable in Community Noise 5 dB Noticeable Difference A-Weighting: dBA Frequency Weighting To Represent Human Hearing Sensitivity

How Loud Is It?

Noise Metrics Leq - Equivalent Noise Level (Average) Average of Pressure Levels Not dB Values Average of 60 dB and 50 dB = 57.4 dB Equal to Continuous Level With Same Energy CNEL 24 Hour Average Noise Level Evening (7 pm to 10 pm) 5 dB Penalty Night (10 pm to 7 am) 10 dB Penalty Well Correlated With Community Response

Adding Noise Levels 50 dB + 60 dB ≠ 110 dB 50 dB + 60 dB = 60.4 dB 60 dB + 60 dB = 63.0 dB Increase Depends on Difference Between Two Levels Being Added

Adding Noise Levels Difference in dB of Two Levels Add to Higher dB To Get Total

Santiago Hills II East Orange General Plan Noise Assessment Describes Existing Conditions Analyses Environmental Noise Impacts from Project & Cumulative CEQA Guidelines & Case Law Industry Standards Prescribes Mitigation to Reduce Impacts

Existing Conditions Applicable Noise Criteria City’s Noise Ordinance Part of Municipal Code (Chapter 8.24) Noise Generated on One Property Impacting Adjacent Property Control Transportation Sources Exempted City’s General Plan Transportation Sources Standards for New Development Residential Exterior - 65 CNEL Residential Interior - 45 CNEL

Existing Conditions Noise Measurements 10 Locations “Snapshot” of Noise Environment Determine If There Are Any Atypical Noise Sources Existing Traffic Noise Levels Modeled Based on Traffic Volumes and FHWA Highway Noise Model Very Reliable & Accurate Generalized By Link - Not Site Specific

Project Impacts Short-Term Impacts Construction Noise Long-Term Off-Site Impacts Traffic Noise (More Discussion On This Later) On-Site Activities Long-Term On-Site Impacts Traffic Noise Off Site Activities On-Site Activities

Cumulative Impacts Off-Site Traffic Noise

Mitigation Measures Construction Noise Impacts Noise Ordinance Restrictions on Hours of Activity Blasting Noise Control Program Long-Term Off-Site Impacts No Significant Impacts Long Term On-Site Impacts Buyer Notification for Aircraft Over Flights Meet City Standards Analysis Shows Attainment Feasible Studies Required Prior to Grading Plan and Building Permit Issuance

Off-Site Traffic Noise Impacts Significance Thresholds Calculating Traffic Noise Level Changes Examples of Changes Results of Analysis

Significance Thresholds Project Impact The Project will result in a significant off-site traffic noise impact if traffic generated by the Project increases noise levels by 3 dB or more AND outdoor noise levels at an area with a noise standard designated by the City exceeds that standard. As the City only has outdoor standards for residential uses, 65 CNEL, these are the only potentially impacted uses.

Significance Threshold Cumulative Impact A significant cumulative off-site traffic noise impact will occur if future with Project noise levels are projected to increase by 3 dB or more over existing conditions AND outdoor noise levels at an area with a noise standard designated by the City exceeds that standard. The Project will have considerably contributed to this increase if it contributes 1 dB or more to the increase.

Calculating Traffic Noise Level Changes Based on Ratio of Average Daily Traffic Volumes From Traffic Study Ratio of Future Without Project to Future With Project Traffic Volume Gives Increase Due to Project Ratio of Existing to Future With Project Traffic Volume Gives Cumulative Increase When Increase Above Threshold is Identified Then Absolute Level is Determined at Sensitive Receptor

Existing + Project

Year 2010

Year 2025

2025 with MPAH Amendments

2025 w/ MPAH Ammend. Alt 3

Off-Site Traffic Noise Impacts Due to Project The project does not result in any traffic noise levels of 3 dB or greater on any road outside the project boundaries. Therefore, the project does not result in a significant noise impact.

Cumulative Off-Site Traffic Noise Impacts with Project Six Road Segments With Cumulative Traffic Noise Increases of 3 dB or Greater Chapman Avenue Newport Boulevard to Jamboree Road Jamboree Road Tustin Ranch Road to Portola Parkway SR-241 SR-91 to Chapman Ave./Santiago Canyon Rd. Chapman Ave./Santiago Canyon Rd. SR-261 SR-241 to Portola Parkway Portola Parkway to Irvine Boulevard

Cumulative Off-Site Traffic Noise Impacts With Project Project Contributes 1 dB or More to Cumulative Increase Along Only One of These Segments Chapman Avenue Between Newport Boulevard and Jamboree Road Future Noise Levels Modeled To Remain Below 65 CNEL at Residential Uses in Future, Therefore, No Impact. Traffic Noise Levels at Residential Uses Along Other Segments Likely to Remain Below 65 CNEL.

Cumulative Off-Site Traffic Noise Impacts with MPAH Ammend. Nine Road Segments with Cumulative Traffic Noise Increases of 3 dB or Greater Santiago Canyon Road F-Street to Silverado Canyon Road South of Silverado Canyon Road North of Live Oak Canyon Road Chapman Avenue West of Newport Boulevard Newport Boulevard to Jamboree Road Jamboree Road North of Tustin Ranch Road Tustin Ranch Road to Portola Parkway SR-241 SR-91 to Chapman Ave./Santiago Canyon Rd. Chapman Ave./Santiago Canyon Rd.

Cumulative Off-Site Traffic Noise Impacts With MPAH Ammend. Project Contributes 1 dB or More to Cumulative Increase Along Only One of These Segments Chapman Avenue Between Newport Boulevard and Jamboree Road Future Noise Levels Modeled To Remain Below 65 CNEL at Residential Uses in Future, Therefore, No Impact.

Cumulative Off-Site Traffic Noise Impacts With MPAH Ammend. Traffic Noise Levels at Some Residences Along Chapman Avenue West of Newport Boulevard Currently Exposed to Traffic Noise Levels in Excess of 65 CNEL and Will Continue to Be in The Future. Traffic Noise Levels at Residential Uses Along Other Segments Likely to Remain Below 65 CNEL.