Motor vehicle noise emissions, when measured according to the rules of this part, shall not exceed the values specified in Table 1.
Table 1--Maximum Permissible Sound Level Readings (Decibel (A)) \1 2\----------------------------------------------------------------------------------------------------------------
Highway operation test Stationary tests
-------------------------------------------------------------------
Soft site Hard Site
--------------------------------------------
35 mi/h Above 35 35 mi/h Above 35 Soft site Hard site
or less mi/h or less mi/h----------------------------------------------------------------------------------------------------------------If the distance between the microphone
location point and the microphone target
point is--
31 ft (9.5m) or more but less than 35 ft 87 91 89 93 89 91
(10.7m)................................
35 ft (10.7m) or more but less than 39 86 90 88 92 88 90
ft (11.9m).............................
39 ft (11.9m) or more but less than 43 85 89 87 91 87 89
ft (13.1m).............................
43 ft (13.1m) or more but less than 48 84 88 86 90 86 88
ft (14.6m).............................
48 ft (14.6m) or more but less than 58 83 87 85 89 85 87
ft (17.1m).............................
58 ft (17.1m) or more but less than 70 82 86 84 88 84 86
ft (21.3m).............................
70 ft (21.3m) or more but less than 83 81 85 83 87 83 85
ft (25.3m).............................----------------------------------------------------------------------------------------------------------------\1\ The speeds shown refer to measurements taken at sites having speed limits as indicated. These speed limits
do not necessarily have to be posted.\2\ This table is based on motor carrier noise emission requirements specified in 40 CFR 202.20 and 40 CFR
202.21. [40 FR 42437, Sept. 12, 1975, as amended at 54 FR 50385, Dec. 6, 1989]