Abstract
The truck driver may be confined to the driving compartment of the vehicles for long periods of time. Here he may be subjected to stresses such as vibration, noise, air contaminants, heat stress, glare of lights or sunshine. The exposure of truck drivers to noise was evaluated in numerous custom-built conventional cab vehicles (not cab over). The source and character of the noise, the inoise reduction achieved, and the noise reduction techniques utilized are reviewed. Maximum allowable noise level specifications of 90, 188, and 85 dBA, within the cab, were attained by the truck manufacturers at minimal cost and vehicle weight increase. The most effective combination of noise reduction techniques attained a maximum level of 83 dBA under all driving conditions (with windows and air vents closed).