When a simple solution to a problem exists, an administrator will usually prefer a gummy one. I have already suggested that a simpler way to calculate the ambient noise increase would be to measure the sound signals of the community. The assumption would be that the level of ambient noise would rise in proportion to social signals, which must always remain above it. We did this for Vancouver by measuring the sound levels of different fire engine sirens, beginning with a 1912 La France device (88-96 dBA) and concluding with the newest 1974 siren (114 dBA), all measured at a distance of 3½ to 5 meters. This showed that the signals of emergency vehicles had risen some 20 to 25 decibels in sixty years, or nearly half a decibel per year on the average.

Schafer, Murray R, The Soundscape- Our Sonic E…, loc. 625