There are some insufficiencies in the Hearing Conservation Program that are exponentially exacerbated by lack of the standard and observation for this program and little interest in team work activities. Regarding the noise measurement instruments, limitation in the measurement lack of the equipments and also incomplete evaluation are clearly detected.The performed investigations have demonstrated that most of the industrial centers have no baseline auditory curve and sometimes do not intend in hearing screening evaluations. that is mainly because of the need for sound protected environment and calibrated instruments and also 14 hours of sound rest before the experiment.Her the problems in performing hearing conservation program is discussed in more details.

We measured the noise caused by Vehicles and its subjective effects in the Modarres high way In Tehran. we examined 143 cases in 11 stations in the mentioned pathway with an accuracy of 95%  and a standard deviation of 39%. The noise criteria of Leq and the number of vehicles were determined in dBA. The loudness contours were also measured in some stations to determine the subjective impacts of noise. Then the correlation of the responses of the interviewees with sound pressure level was measured. Based on our findings, decrease of  the noise of traffic sources should be considered three levels: the first level is noise reduction at the level of source, e.g. the vehiclesthe second is Noise reduction at the traffic level and the third is noise reduction at the level of general activity.