Durango, CO Pagosa Springs, CO Albuquerque, NM Farmington, NM October 2019 Traffic Noise Analysis NM 599-US 84/285 On-ramp Improvements Milepost 165.5 to MP 166.5 Santa Fe County – New Mexico Control Number S100430 Prepared for: Radian Engineering, LLC 509 Camino de los Marquez, Suite 2 Santa Fe, New Mexico 87501 On Behalf of New Mexico Department of Transportation and Federal Highway Administration Prepared by: Ecosphere Environmental Services, Inc. 320 Osuna Road NE Building C, Suite C-1 Albuquerque, New Mexico 87107 505-954-1570
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Traffic Noise Analysis 599...eq equivalent noise level NAC noise abatement criteria NMDOT New Mexico Department of Transportation NM 599 New Mexico State Highway 599 Project NM 599-US
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Durango, CO
Pagosa Springs, CO
Albuquerque, NM
Farmington, NM
October 2019
Traffic Noise Analysis NM 599-US 84/285 On-ramp
Improvements
Milepost 165.5 to MP 166.5
Santa Fe County – New Mexico
Control Number S100430
Prepared for:
Radian Engineering, LLC 509 Camino de los Marquez, Suite 2 Santa Fe, New Mexico 87501 On Behalf of New Mexico Department of Transportation and Federal Highway Administration
Prepared by: Ecosphere Environmental Services, Inc. 320 Osuna Road NE Building C, Suite C-1 Albuquerque, New Mexico 87107 505-954-1570
2. Federal Highway Administration/New Mexico Department of Transportation Noise Policies and Procedures ........................................................................................................................................ 3
dB decibel dBA A-weighted decibel Ecosphere Ecosphere Environmental Services, Inc. FHWA Federal Highway Administration Leq equivalent noise level NAC noise abatement criteria NMDOT New Mexico Department of Transportation NM 599 New Mexico State Highway 599 Project NM 599-US 84/285 On-ramp Improvements TNM Traffic Noise Model US 84/285 U.S. Highway 84/285
2. Federal Highway Administration/New Mexico Department of Transportation Noise Policies and Procedures
Because this Project uses FHWA and NMDOT funding, it must follow state and federal traffic noise
policies, including the NMDOT’s Infrastructure Design Directive IDD-2011-02: Procedures for Abatement
of Highway Traffic Noise and Construction Noise (NMDOT 2011) and the FHWA’s Highway Traffic Noise:
Analysis and Abatement Guidance (FHWA 2011). Under these guidelines, the relative loudness of noise
is described in decibels (dB), a measure of sound pressure on a logarithmic scale. For highway noise
studies, traffic noise is averaged over a 1-hour peak noise period and is expressed as an equivalent noise
level (Leq). An A-weighted filter is also used to correlate physical noise levels with the frequency
sensitivity of human hearing and the subjective response to noise. Thus, noise conditions are generally
discussed in terms of hourly average A-weighted noise levels in decibels, or dBA Leq.
The noise standards of the NMDOT and FHWA are based on a 1-hour dBA Leq, calculated during the peak
hour of traffic noise. According to FHWA and NMDOT procedures, noise abatement must be considered
when predicted traffic noise levels approach or exceed specified noise abatement criteria (NAC) defined
for various land-use categories or when predicted future noise levels exceed existing levels by 10 dBA or
more. NMDOT’s noise policy defines “approach” as being within 1-dBA of the appropriate NAC (Table 1).
Table 1. Noise abatement criteria from 23 Code of Federal Regulations, Part 772
(average A-weighted decibels [dBA Leq])
Activity Category
Activity Criteria
Activity Location
Activity Location
A 57 Exterior Lands on which serenity and quiet are of extraordinary significance and serve an important public need, and where preservation of those qualities is essential if the area is to continue to serve its intended purpose.
B 67 Exterior Residential.
C 67 Exterior Active sports areas, amphitheaters, auditoriums, campgrounds, cemeteries, daycare centers, hospitals, libraries, medical facilities, parks, picnic areas, places of worship, playgrounds, public meeting rooms, public or nonprofit institutional structures, radio studios, recording studios, recreation areas, Section 4(f) sites, schools, television studios, trails, and trail crossings.
D 52 Interior Auditoriums, daycare centers, hospitals, libraries, medical facilities, places of worship, public meeting rooms, public or nonprofit institutional structures, radio studios, recording studios, schools, and television studios.
E 72 Exterior Hotels; motels; offices; restaurants/bars; and other developed lands, properties, or activities not included in previous A-D or F activity categories.
F NA NA Agriculture, airports, bus yards, emergency services, industrial, logging, maintenance facilities, manufacturing, mining, rail yards, retail facilities, shipyards, utilities (water resources, water treatment, electrical), and warehousing.
G NA NA Undeveloped lands that are not permitted.
Source: Federal Highway Administration 2011.
3. Existing Conditions
The Project area on the north side of the City of Santa Fe extends through vacant land with some areas
of high-density residential development. On the east side of US 84/285 is the Santa Fe National
Cemetery and a single-family residential development that is shielded by a noise wall constructed when
US 84/285 was improved in this area in 2000-2001. This area is not considered further.
On the west side of US 84/285, the primary noise areas include high-density residential development in
the Zocalo Condominiums, Reserve at Santa Fe Condominiums, Los Piñones Apartment Homes, and
other multi-family units around Viento Drive. Most of these are two story units and many have second
floor, outdoor balconies.
Just west of the ramp diverge point on NM 599, the road crosses the Cañada Rincon arroyo. The on-
ramp climbs in elevation to the US 84/285 merge, then drops in elevation to the south along US 84/285.
Cañada Rincon parallels US 84/285 to the west but for most of the length of the on-ramp, low hills and
an earthen berm are situated between the roadway and arroyo. This hilly, higher terrain is above the
road elevation and creates a visual and noise barrier between the highway and the Zocalo residential
development to the west. At about MP 165.9, the Cañada Rincon is immediately adjacent to the
embankment of US 84/285. In 2000-2001, a noise wall was constructed in this area at the edge of the
road because there is no room for a berm between the road and arroyo, and several residential
condominiums (Zocalo) are relatively close to the highway. As US 84/285 extends south from the noise
wall, the Cañada Rincon continues immediately west of the road and intervening terrain does not occur
between the highway and residential development west of the arroyo.
To evaluate noise impacts, ten receivers (sites where noise levels are modelled) were defined to
represent the residential areas most likely to be affected by Project noise. These are described below
NMDOT Design Directive IDD-2011-02 (2011) stipulates that noise analyses conducted for existing
alignments should use predictions (modeling) to determine existing and design year traffic noise impacts
(Section 5.00a2) and that predicted noise levels should be validated through comparison of measured
and predicted levels (Section 5.00a11). To compare predicted and measured noise levels, the FHWA’s
Traffic Noise Model (TNM) (Version 2.5) (FHWA 2004) was used with existing traffic counts and site
conditions to predict noise levels at a location where measurements were taken. Noise measurements
and simultaneous traffic counts were collected on August 28, 2019 from approximately 8:50 to 9:07
AM1. The measurement location was on the west side of US 84/285 just south of the NM 599 merge
point and approximately 30 feet from the edge of the southbound driving lane at the same grade as the
roadway. This location provided a direct line-of-sight to the roadway traffic lanes, allowing directional
traffic counts and classification of autos, medium trucks (two axles but more than four tires), and heavy
trucks (three or more axles). Average traffic speed was estimated at 65 miles per hour on US 84/285 by
driving with the flow of traffic in the corridor. The counts (converted to hourly totals) and
measurements are shown in Table 2.
Table 2. Validation traffic volumes (vehicles per hour) and noise levels (dBA Leq)
Count Location/Period Autos
Medium Trucks
Heavy Trucks
Measured Noise
Modeled Noise
Difference (Measured- Modeled) NB SB NB SB NB SB
US 84/285 Mainline August 28, 2019
818 1482 11 43 43 25 77.6 76.5 0.9
Note: NB=northbound; SB=southbound.
Existing noise levels were calculated for the measurement site using the TNM model with inputs that
matched the location and traffic conditions at the time of the measurements. The TNM model uses site-
specific information on traffic volumes and speeds, vehicle classifications, roadway geometry, and site
acoustical properties to predict hourly noise levels at selected locations. The measured and modeled
noise levels were compared to validate the assumptions used in the model. The August 2019 traffic and
site data were entered as inputs into the TNM model. The results are shown in Table 2 compared to the
measured noise levels. The modeled and measured levels vary slightly but are well within the generally
accepted tolerance of 3 dBA.
1 Statistical accuracy requires minimum measurements of approximately 8 minutes. Most highway agencies typically use 15-minute time periods to represent the Leq (FHWA 2011). Noise was measured using a Larson Davis Sound Track LxT1, Type I Integrating Sound Level Meter (serial number 5742), which was calibrated before and after the measurement session. Atmospheric conditions were clear and wind speed was light and variable during noise data collection and had little effect on sound propagation.