My hearing in one ear is worthless in a noisy area... make sure they also test you with white noise background in the booth... plus, don't guess at any word you aren't sure of in a test, as some techs think that if you get the main center of the word, you can hear! (Which means it would be just find for them if we heard a nasty word instead of truck!)

I have a masker for one ear with high tinnitus, to block out the noise from the speech.