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Santa Clarita Development
Construction Noise Review
Project No. 25.0170
April 16, 2025
Tai Lane, Senior Development Manager
Serrano Development Group
24 North Marengo
Pasadena, California 91101
Dear Tai,
Westside Acoustics and Vibration Engineering (Westside) has evaluated the subject project for expected exterior construction noise level production to the surrounding community; particularly to the nearby radio station (KHTS Radio), which has expressed concern over construction activities. Westside has evaluated expected construction noise levels to this particular receptor and compared these to existing environmental noise levels that the KHTS Radio experiences to opine on the true impact of the anticipated construction noise. This letter documents our findings and conclusions.
1.0 EXECUTIVE SUMMARY
The full analysis of existing noise exposure and future anticipated construction noise exposure to the nearby radio station to the subject project are included in the following sections. However, below is a brief summary of Westside’s findings:
• Due to the nearby railroad, which includes freight train passby’s, the radio station is currently exposed to high noise levels.
• Calculated construction noise level activities, assuming standard construction noise mitigation measures, are comparable to the existing noise environment. • It is Westside’s professional opinion that construction noise should not substantially impact the radio station given it is not expected to be louder than the current noise environment.
2.0 EXISTING NOISE EXPOSURE
As a benchmark for comparison, Westside has evaluated existing noise levels at the radio station in question from two separate sources. Anticipated construction noise levels will be compared to these results in the next section.
2.1 Newhall Mixed-Use Acoustical Report
An acoustical analysis report, prepared by another consultant, was provided for a nearby project. The report is titled “Old Town New Hall Mixed-Use” and was prepared Westside Project No. 25.0170
Santa Clarita Development
Construction Noise Review
April 16, 2025 | Page 2 of 5
November 8, 2016 by Christopher Jean & Associates Inc. This project is located at the corner of Railroad Avenue and Lyons Avenue, but is partially shielded from railroad and traffic noise along Railroad Avenue by another building.
Based on data presented in this report, Westside expects the east façade of the radio station is subject to an average daytime hourly noise level of approximately 70 dB solely due to train activity (entirely controlled by freight train noise). Note there is no substantial difference in expected noise level at the radio station compared to the report subject building due to similar setback distances (< 1dB). See Figure 1 below showing an aerial image of the subject project site and radio station relative to the nearby railroad.
Figure 1: Aerial Site Map
2.2 Freight Train Noise Analyses
Per the nearest crossings inventory data provided by the Department of Transportation (DOT) Federal Railroad Administration (FRA) Office of Safety Analysis website, train crossing events consist of both commuter and freight trains. For the purposes of this analysis, Westside has solely evaluated noise from freight train passby’s. The crossing inventory report indicates that this area is not a “quiet zone;” which means that trains are required to sound their horns as they approach a crossing with a roadway. Train horns are generally the loudest part of a train operations when moving through a crossing.
Westside Project No. 25.0170
Santa Clarita Development
Construction Noise Review
April 16, 2025 | Page 3 of 5
Westside utilized previously measured freight train noise data from other projects to evaluate expected noise levels from single-event train passby’s at the radio station. After adjusting for appropriate measurement distance (185-feet, see previous section), freight train events are expected to be approximately between 76 dB and 82 dB. Freight train events can last anywhere from 120 seconds to over 5 minutes depending on the size, speed, length of train and whether or not there are delays in operations.
3.0 EXPECTED CONSTRUCTION NOISE EXPOSURE
3.1 Typical Construction Equipment
Given the subject project size and scope, Westside has anticipated typical construction equipment used for a construction project of this nature but has limited analysis to the “noisiest” equipment pieces. Table 1 below is the list of equipment used in the following analysis. Construction phases are bundled based on types of equipment anticipated, not actual construction schedule. Equipment sound levels and analysis methodology are all per the Federal Highway Administration (FHWA) Highway Construction Noise Handbook (August 2006, Final Version).
Table 1: Expected Construction Equipment
Construction Phase Anticipated Equipment
Demolition Backhoe, Bulldozer, Crane, Excavator
Grading/Excavation
Backhoe, Bulldozer, Crane, Excavator,
Front-end Loader, Generator, Grader,
Jackhammer, Paver, Truck(s), Pile Driver
(screw or vibration)
Building Construction
Crane, Concrete Mixer Truck, Concrete
Saw, Generator, Pneumatic Tool(s),
Truck(s)
3.2 Calculated Construction Noise Levels
In addition to equipment being separated into different phases based on use, analysis of construction noise exposure was separated based on anticipated separation distances:
average separation distance, minimum separation distance, and truck-route distances.
1. The average separation distance analysis takes all equipment sound levels into consideration simultaneously and assumes they are all located at the project center. This is of course never the case but is the average physical distance each piece of equipment would likely be away from the radio station building at any given time, or over the course of the phase of construction. This could be considered the “average” noise exposure level.
Westside Project No. 25.0170
Santa Clarita Development
Construction Noise Review
April 16, 2025 | Page 4 of 5
2. The minimum separation distance only accounts for one equipment piece at a time and assumes the minimum separation distance between the project boundary and the radio station. This could be considered the “maximum” noise exposure level.
3. The truck route is unique because it is the only noise source that is not bound by the property boundary; trucks deliver materials to or remove materials from the site. Typical construction plans often include strategic truck routing to avoid sensitive receptors for noise, and other reasons. It is assumed that this will be implemented and therefore this noise source is not included in the analysis.
Finally, this assessment assumes that typical construction mitigation measures are implemented, including but not limited to properly functioning, adjusted mufflers on appropriate equipment, limiting construction hours to those specified in the city municipal code, locating continuously running equipment (e.g., generators, pumps, etc.) away from sensitive noise receptors, strategic truck routes, and conducting a more in depth construction noise study.
See Table 2 below for Westside’s calculated construction noise exposure levels per the discussion items above.
Table 2: Calculated Construction Noise Levels
Construction
Phase
Construction Noise Level
[dB] per Setback Distance
Calculated Freight Train
Exposure Noise Levels [dB]
Average
Separation
Minimum
Separation Average Maximum
Demolition 77 79
76 82 Grading/Excavation 79 80
Building
Construction 77 79
These calculated noise levels are comparable to those of the typical train operations evaluated in section 2.0.
4.0 CONCLUSIONS
Westside understands that a nearby radio station to the subject project has expressed concerns over construction noise exposure affecting their operations. Westside has conducted an evaluation of anticipated existing noise exposure to the radio station due to transit noise sources and compared these levels to calculated construction noise levels expected to reach the station.
Existing noise exposure to the radio station is expected to be high, both on an hourly average noise level basis and a single event level basis, due to the adjacent railroad which has regular freight train passby’s.
Westside Project No. 25.0170
Santa Clarita Development
Construction Noise Review
April 16, 2025 | Page 5 of 5
Construction noise level exposure to the radio station was calculated based on typical equipment expected for a project of this nature and assuming typical construction noise mitigation measures. Noise levels were found to be comparable to those already experienced due to train activities.
Given the existing high-noise acoustic environment created by nearby train activity, it is Westside’s professional opinion that construction noise will not substantially add to the noise environment and therefore would not represent a substantial acoustic impact.
Please feel free to contact us with any questions.
Sincerely,
Westside Acoustics
John LoVerde, FASA
Acoustician