Relation of noise measurements to temporary threshold shift in snowmobile users

To evaluate and quantify snowmobile noise, measurements were made as follows: (1) operator at-ear A-weighted sound levels and exposure patterns; (2) A-weighted levels at 50 ft to develop a test procedure for law enforcement purposes; (3) temporary threshold shift (TTS) in snowmobile users. Results indicate that (a) TTS of varying degrees was observed in 87% of snowmobile operators tested after operations periods as short as one-half hour; (b) for typical recreational riding, the Federal Occupational Safety and Health Act of 1970 noise limits are exceeded after approximately 2 1/2 hours of snowmobile operation; (c) the 50-ft noise-level measurement procedure which was developed can probably be used as a valid test procedure to measure the amount of noise produced by a snowmobile for law enforcement purposes. More correlation of data would be desirable.