"Calling noise a nuisance is like calling smog an inconvenience. Noise must be considered a hazard to the health of people everywhere."
William H. Stewart, former U.S. Surgeon General
Because noise is invisible, its impact on the surrounding environment is often more difficult to recognize than is the case with chemical pollutants found in the air or water. However, the effects of noise on our lives are very real. Noise is not a "non-quantifiable" emission and its effects can no longer be regarded as "indeterminate". It is a misconception that people can adjust to noise by ignoring it or "getting used to it". The ear never closes and even responds to sound during sleep!
What does noise do to our health?
How do vehicular noise levels compare?
Noise is measured in decibels. The decibel scale is a logarithmic scale. The intensity or "power" of a sound doubles roughly every 10 decibels. The noise level on a typical city street with automobile traffic averages 60-65 db; larger vehicles like heavy trucks and diesel buses cause noise peaks ranging up to about 90 db. The following chart gives the values on the decibel scale associated with various types of vehicles; the measurements were made with the vehicles travelling in urban conditions between 45 and 60 km/h.
|Type of Vehicle
|Noise in decibels
|Gasoline passenger car
|Electric trolley bus
|Urban diesel bus
|(Adapted from: Transport Action, Transport Canada 2000, October 2001; additional data from BC Transit, 1999 and Calgary Transit)
Typically, city traffic engineers and planners measure the noise generated by vehicular traffic in a give corridor as an average over a specific time period. However, this type of measurement is actually misleading in determining the effects of traffic noise on the community. Noise experts agree that intermittent and impulsive noise is far more disturbing than continuous noise. Diesel buses and trucks passing at intervals may exert little influence on average noise levels over a time period, but the effects on community health produced by the peaks that they create in the noise level are significant.
How does this relate to my community?
Edmonton civic records show that the noise levels from both diesel buses and heavy trucks are a concern to residents. To some extent, the problem of noise from heavy trucks has been addressed through the establishment of fixed truck routes and the installation of noise attenuation measures (berms) along freeways and heavy traffic corridors. However, the noise from diesel transit buses has never been satisfactorily addressed. These vehicles are permitted to operate freely in ever increasing numbers in otherwise quiet residential neighborhoods as well as in high density areas.
Electric public transportation modes such as the trolleybus and light rail do not create the noise problems associated with diesel buses. The increased use of electric modes is clearly conducive to building healthier communities in Edmonton.
Transport Canada 2000, Noise Centre (League for the Hard of Hearing), BC Transit, Calgary Transit, City of Edmonton departmental correspondence.