What are the hearing requirements and how do they differ from the vision requirements?
As per FMCSA 391.41 (b) (11):
“A person is physically qualified to drive a commercial motor vehicle if that person —
First perceives a forced whispered voice in the better ear at not less than 5 feet with or without the use of a hearing aid or, if tested by use of an audiometric device, does not have an average hearing loss in the better ear greater than 40 decibels at 500 Hz, 1,000 Hz, and 2,000 Hz with or without a hearing aid when the audiometric device is calibrated to American National Standard (formerly ASA Standard) Z24.5–1951.”
In reviewing the hearing standard above notice that it says “better ear”. So the driver is required to meet the standard in one ear not both. That differs from the vision standard where monocular vision is disqualifying, and the driver must meet the vision standard with both eyes. (click link for detail on vision requirements). The screening tests that can be administered to test for hearing are the forced whisper test and the audiometric test, and either one can be done first. Since most medical examiners are unlikely to own an audiometer, most drivers will be first tested with the forced whisper test and referred out for audiometric testing if the driver could not pass the forced whisper with both ears. If a driver wearing a hearing aid fails the forced whisper test, he will need to be referred to an audiologist or other ear specialist or hearing aid center. Although the accuracy and value of the forced whisper test has been questioned, it remains a quick and convenient way to screen for gross hearing deficits. (Note that the same doubts have been cast on confrontational vision testing to screen for peripheral visual field abnormalities as discussed in an earlier post). The forced whisper and audiometric tests are designed to evaluate hearing loss in frequencies found in normal conversation.
If the driver meets the hearing standard above, he or she may be qualified for up to 2 years if no other limiting medical conditions are found on physical examination.
391.41 (b) (11):
When a hearing aid is used to meet the hearing qualification requirement, the hearing aid must be used while driving.
Disqualify when both the forced whisper test AND the audiometric test are failed.