*Purpose and findings. This district:

• Protects public health and conserves the habitability and value of residential properties in the vicinity of high-volume highways.

• Establishes the setback standards for "noise impacted residential uses" from certain highways identified on the Zoning Ordinance Map, "Highway Noise Impact Overlay District" in order to mitigate the highway noise; providing for certain reductions in setback distance under certain circumstances; and allowing for required lot and structure design.

• Assures the City of Frederick's eligibility for participation in the Type II noise barriers program under the "Sound Barrier Policy" issued by the State Highway Administration in May of 1998.

(a)

District Boundaries.

(1)

The Highway Noise Impact Overlay District boundaries shall be based on the State Highway Administration's (SHA) analysis of highway-related noise that approach or exceed 67 decibels Leq, using the Federal Highway Administration's (FHWA) Traffic Noise Model 2.5. Approach shall be defined as 66 decibels Leq.

(2)

For the purpose of administering such regulations the following Highway Noise Impact Areas are established, and depicted on the Official Zoning Map(s) of the City of Frederick:

(b)

Overlay District Established. The Highway Noise Impact Overlay District is established as an overlay district. Land within the Highway Noise Impact Overlay District may be used as permitted in the underlying district only if and to the extent such use is also permitted in the overlay district and subject to the additional overlay regulations. Infill developments on lots three acres in size or less recorded prior to August 15, 2005 shall be exempt from the provisions of Section 422.

(c)

Use Limitations. In addition to the use limitations and regulations for the zoning district over which the Highway Noise Impact Overlay District is located, the use limitations in subsections (d) through (e) shall apply.

(d)

For Residential Areas. The developer of any "noise impacted residential uses" shall subdivide and/or construct in accordance with one of the following alternatives:

(1)

For all new residential subdivisions, as of August 15, 2005, no residential single-family detached or townhouse lots are to be created within the Highway Noise Impact Overlay District, and all residential lands within the Highway Noise Impact Overlay District are dedicated to homeowners association for open space purposes. Notwithstanding the above, if the applicant proposes to construct within the prescribed distances of subsection (a), the provisions of subsection (d)(4) must be followed.

(2)

For all new residential subdivisions of multifamily housing, as of August 15, 2005, all noise sensitive use areas within a "Noise Impacted Residential Use" that experience frequent human usage shall have the placement of the multifamily residential structures setback from the designated highways as prescribed in subsection (a). Notwithstanding the above, if the applicant proposes to construct within the prescribed distances of Subsection (a), the provisions of subsection (d)(4) must be followed.

(3)

For all existing residential lots and approved preliminary subdivisions as of August 15, 2005, all noise sensitive use areas within a "Noise Impacted Residential Use" that used on a daily basis shall have the placement of the residential structure setback from the designated highways as prescribed in subsection (a), but may be modified by the Planning Commission if determined to not reasonably be possible. If applicant proposed to construct within the prescribed distances of subsection (a), the provisions of subsection (4) must be followed.

(4)

Noise Impact Analysis and Mitigation.

A.

A noise impact study shall be conducted by a demonstrated qualified acoustical engineer with experience in highway noise analysis to determine the worst case decibel level based upon highway capacity Level of Service "D", at noise sensitive use areas using FHWA documentation: "Measurement of Highway Related Noise" Final Report, May 1996. The State Highway Administration will provide the City with advice on the technical accuracy of noise impact studies.

B.

The setback established in subsection (a) may be reduced by the Planning Commission during the subdivision and site plan review process, if it is determined that the noise impact setback distance needed to maintain traffic noise levels lower than 66 decibels in areas of the property that are noise sensitive. If at that time, the applicant can construct the proposed residential structure(s) outside the 66 decibel area, then no further mitigation is necessary and approval of the subdivision or site plan can proceed with no HNO restriction (for the relevant areas of the subject parcel(s)).

C.

If it is determined that highway noise mitigation measures are proposed to address the impact of highway noise on residential uses, and to insure reduced noise impact, the Planning Commission may approve a preliminary or final subdivision plat or a final site plan with the condition of implementing noise mitigation measures to reduce the decibel levels as follows:

1.

For single-family homes at the residential lot line a projected level of 63 decibels shall be required.

2.

For townhouse homes at the residential lot line a projected level of 65 decibels shall be required.

3.

For multifamily development at the proposed building footprint a projected level of 65 decibels shall be required. In the case of proposed multifamily on existing recorded lots, if it can be demonstrated by the applicant that noise mitigation cannot be reasonably implemented to reduce levels to 65 decibels at the building footprint, then alternative construction measures may be approved as mitigation measures to achieve interior noise levels of 45 decibels. Prior to issuance of the Certificate of Use and Occupancy, verification of the acoustical treatment to achieve the 45 decibels shall be conducted through field testing, certified by an acoustical engineer.

(e)

Acoustical Treatment. The developer of any residential use that is within the Highway Noise Impact Overlay District shall incorporate acoustical treatment into all dwelling units to insure that interior noise levels within living spaces (not including garages, sun rooms, or porches) do not exceed a sound level of 45 decibels dBA (Leq). Prior to issuance of the Certificate of Use and Occupancy, verification of the acoustical treatment to achieve the 45 decibels shall be conducted through field testing, certified by an acoustical engineer.