NOISE IN COMMERCIAL VEHICLE CABS, THE EFFECT OF NOISE ON HEARING

The effect of noise on hearing acuity is explained, and the latest criteria for risk of hearing damage are reviewed and illustrated. The noise levels in commercial vehicle cabs are examined in the light of hearing-damage risk; it is concluded that although there is little risk of damage during A road driving, there may be at present some risk during motorway driving. This latter risk will undoubtedly be increased in the future as the number and lengths of motorways increase, thus theoretically allowing the driver to be subjected to continuous high noise levels for the maximum time (5 1/2 hours) permitted by the Road Traffic Act. In order to afford some protection to the hearing of commercial vehicle drivers, it is proposed that the maximum noise level in a cab should not exceed 95 dB(A); if this limit is exceeded an economic sound reduction programme can be based upon an octave analysis of the cab noise, obtained for the purpose.(Author)