Low Frequency Noise Under Interrupted Flow Conditions

In 1978 SCPR published the results of a social survey of attitudes to road traffic usually referred to as the National Environmental Survey (I) .The Survey, carried out in 1972, was broadly representative of the adult population in England.and assessed.amongst other factors, the disturbance caused by traffic noise and vibration to people when indoors at home.The survey showed that whilst vibration was less widespread than noise it was considered to be a serious source of bother by those affected.The results were similar to those of an earlier study in Edinburgh ( 2) in which about one in ten of the sample Considered notlceahle vibration' to be prevalent.In the Edinburgh study, carried out in 1969, crude measurements were made of both kerbside vibration levels and broad band low frequency sound levels.Vibration was measured using a shielded accelerometer the output fed via a cathode follower into a Dawe type 1433 vibration meter set to the velocity scale.The traffic noise was filtered using a low pass filter (less than lOOHz) fitted to a Dave MODE sound level meter set to the C weighting scale.The analyses of recordings at some 150 sites was based on meter readings taken from time lapse films at 4 second intervals.Kean vibration levels varied approximately linearly with traffic volume with the highest levels recorded in streets with substantial flows of heavy vehicles.In some locations these average levels were close to 0.015 in/s (0.0004m/5) the