FHWA Noise Table

TABLE 1 FHWA NOISE ABATEMENT CRITERIA¹ (NAC), HOURLY A-WEIGHTED SOUND LEVEL IN DECIBELS (dBA)
Activity Category	Leq (h)	L₁₀(h) ²	Description of Activity Category
A	57 (exterior)	60 (exterior)	Lands where serenity and quiet are of extraordinary significance and serve an important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose.
B	67 (exterior)	70 (exterior)	Picnic area, recreation area, playgrounds, active sports, parks, residences, motels, hotels, schools, churches, libraries, and hospitals.
C	72 (exterior)	75 (exterior)	Developed lands, properties, or activities not included in Categories A or B above.
D	--	--	Undeveloped lands.
E	52 (interior)	55 (interior)	Residences, motels, hotels, public meeting rooms, schools, churches, libraries, hospitals, and auditoriums.

¹Federal-Aid Highway Program Manual; Vol. 7, Ch. 7, Sec. 3, Attachment, Transmittal 348, 8/9/82.
² Either L₁₀(h) or Leq(h) (but not both) may be used on a project. This report uses the L₁₀(h) per MPCA standards.

TABLE 2 NOISE LEVEL STANDARDS OF THE MPCA¹
Category	General Land Use Types	Daytime Noise Levels (7 A.M. to 10 P.M.)	Nighttime Noise Levels (10 P.M. to 7 A.M.)
NAC-1	Residential & Institutional	L₁₀ of 65 dBA L₅₀ of 60 dBA	L₁₀ of 55 dBA L₅₀ of 50 dBA
NAC-2	Commercial & Recreational	L₁₀ of 70 dBA L₅₀ of 65 dBA	L₁₀ of 70 dBA L₅₀ of 65 dBA
NAC-3	Industrial	L₁₀ of 80 dBA L₅₀ of 75 dBA	L₁₀ of 80 dBA L₅₀ of 75 dBA

¹ Minnesota Statutes Chapter 7010--Noise Pollution Control--Subp.