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Home My WebLink AboutCT 97-13; Carlsbad Oaks North; Tentative Map (CT) (19)PAC1FIC -----------------------· -----------------------------------------·-··-·····-------· -------···-·--··------------. -------------- 2! (_) \Voodland Dri.vc: & Vista, CA 92083 l; (760) 758-1198 ll> Fax (760) 75R--4761 May 11, 2004 Mr. Dan ;Eubank Techbilt Construction Corporation 3575 Kenyon Street San Diego, CA 92138 SUBJECT: Carlsbad Oaks North Business Park Project Focused Exterior Traffic Noise Analysis Dear Mr. Eubank: This noise study has been prepared as part of the City of Carlsbad's Conditions of Approval for the Carlsbad Oaks North Business Park project. The purpose of this noise study is to determine if noise barriers are required as a result of Faraday A venue traffic noise, for existing residences within 135- feet of Faraday A venue, west of Melrose A venue. · There are six residences adjacent to Faraday A venue as well as a second tier home located within 135- feet of Faraday Avenue. The five residences along Faraday Avenue, east of Brookhaven Pass, have existing masonry sound walls. As built plans indicating the height of the existing sound walls are not available. Based on a site visit, the height of the existing sound walls is approximately 5.5-feet. 1.0 BACKGROUND Methodology The future CNEL was calculated for the residential lots based on the future year 2020 traffic volume along Faraday Avenue using Caltrans' SOUND32 traffic noise model (Caltrans 1987) with California noise emission factors (1987). Faraday Avenue is currently a two-lane road west of Melrose Drive. In the future, Faraday Avenue is anticipated to be a four-lane road. The future traffic speed for Faraday A venue was assumed to be 40 mph. This is the posted speed limit of Park Center Drive, a four~ lane road immediately east of Melrose Drive (the road name changes to Park Center Drive east of Melrose Drive). The truck mix used in the noise-model is 3. 52% medium trucks and 1. 24% heavy trucks. The vehicle truck mix is based on the City of Carlsbad estimate of the vehicle mix for truck routes (City of Carlsbad 1995). The future year"2020 traffic volume utilized in this study is 30,900 ADT (Willdan 2002). The road elevations were determined using the Faraday Avenue Street Improvement Plans (Escondido Engineering, last revision 12/9/95). The elevations for the homes were determined using the erosion control plans for Canyon Creek Phase IV (Escondido Engineering 1991). Noise Criteria The residences are located in the City of Vista. The City of Vista typically describes community Mr. Dan Eubank Carlsbad Oaks North Business Park Project-Focused Exterior Traffic Noise Analysis May 11, 2004 Page 2 noise levels in terms of the Community Noise Equivalent Level (CNEL). CNEL is the average A- weighted sound level during a 24-hour day. It is obtained after adding five decibels (dB) to sound levels in the evening hours (7 p.m. to 10 p.m.) and adding ten dB to the sound levels at night (10 p.m. to 7 a.m.). The five and ten dB penalties are applied to account for increased noise sensitivity during the evening and nighttime hours. The A-weighted scale measures noise levels corresponding to the human hearing frequency response .. All sound levels discussed in this report are A-weighted. The City has established exterior noise guidelines in the City's General Plan. The maximum acceptable exterior noise level is 65 dB CNEL for single family residences. 2.0 FUTURE NOISE LEVEL Several of the residences adjacent to Faraday A venue would be exposed to a future CNEL greater than 65 dB. The future CNEL would range up to approximately 72 dB at the home located at the northwest corner of Faraday Avenue and Brookhaven Pass. This home does not have an existing sound wall. The future noise level associated with Faraday A venue would range from approximately 64 to 67 dB at the residences along Faraday Avenue, east of Brookhaven Pass. These homes have an existing. approximate 5. 5-foot high sound wall 3.0 MITIGATION To mitigate Faraday A venue traffic noise to 65 dB CNEL or less at the residences would require noise barriers ranging from 6 to 7-feet in height at some of the residences. The noise barriers should be constructed along the top-of-slope of the lots as depicted in Figure 1. The height of the noise barrier is relative to the top of the slope of the backyards at Lots 41 and 42 as identified on Figure 1. The heights of the noise barriers are relative to the pad elevations at the residences located at Lots 43, 128 and 129. The height of the existing wall at Lots 39 and 40 will mitigate the future Faraday A venue noise level to 65 dB CNEL or less at these lots. The noise barriers may be constructed as a wall, berm or combination of both. The noise barriers must have a surface density of at least 3 .5 pounds per square foot, and have no openings or cracks. The wall may be constructed of 5/8-inch acrylic glass, any masonry material or a combination of these materials. If you have any questions, please call me. Sincerely, ?lz/1 ~~ Mike Komula Principal Mr. Dan Eubank Carlsbad Oaks North Business Park Project-Focused Exterior Traffic Noise Analysis REFERENCES May 11, 2004 Page3 California Department of Transportation (Caltrans), June 1983. User's Instructions for SOUND32 (FHWA/CA-83/06). . California Department of Transportation (Caltrans), 1987. California Vehicle Noise Emission Levels, (FHWA/CA/TL-87/03). Carlsbad, City of, September, 1995. City of Carlsbad Noise Guidelines Manual. Willdan, August 5, 2002. Carlsbad Oaks North Traffic Study Local Facilities Management Plan- Zone 16. ...._.,,~·-.. t··- ,,.<Di ~m:oQ~ffi rz1 f ' .. .. . -.-:::: Noise Barrier 0 --===.:=J 0 FEET .80 Base Map Source: Escondido Engineering 1991 Pacific Noise Control Noise Barrier Heights and Locations FIGURE 1