What types of traffic noise are considered when determining sound attenuation?
Traffic noise produced by tires moving against pavement with contributing factors of vehicle type, tire configuration, number of vehicles, and speed.
Noise from modified vehicles and louder motorbikes is not considered because it is not a result of high traffic volumes (they could occur on any local street). These sounds are not well-deterred by sound walls or physical barriers and must be controlled through enforcement.
The City of Leduc Community Standards Bylaw applies to noises that are intermittent, unusual, or unique in nature. This includes engine noise, mufflers, construction, stereos, etc. If residents are concerned about noise from these sources, please call Enforcement Services at 1-780-980-1537.
How traffic noise is measured
The City conducts noise monitoring studies adjacent to major roadways, due to their high traffic volume, to measure sound over a 24-hour period about six feet off the ground in a backyard. Households with an elevated deck impact the desired effects of sound attenuation. The common standard noise level used across the province is 65 decibels to determine if sound walls or physical barriers are needed.
The outcomes of noise monitoring studies result in:
- If measured noise levels are more than 65 decibels, the city looks at installing noise fencing or similar deterrents to bring down sound levels in the backyard.
- If measured noise levels are less than 65 decibels, and the city is doing a road widening project in the area, the levels are modeled out over a 25-year period to see if the sound levels are ever expected to exceed 65 decibels. If they are projected to exceed 65 decibels, the city will proactively install a noise fence as part of the construction project.
The next round of monitoring is being conducted as part of the Transportation Master Plan. The testing will start in fall 2022 and conclude in the summer of 2023. Results are then presented to Leduc City Council.
Result of noise monitoring studies
A traffic noise presentation was made to City Council on Jan. 24, 2022 (1:04:20) by ACI Acoustical Consultants Inc. This included results of previous noise monitoring in the City of Leduc and how sound monitoring is conducted.
Past monitoring results show the areas that experience the most road noise in the City (illustrated in the map below). The red area is adjacent to Willow Park, blue areas experience the second most noise but are below the threshold, and green areas experience the third most noise. The blue and green areas would be examined for noise reduction when noise monitoring levels exceed 65 decibels or when road widening occurs.
The construction of noise reduction measures is considered based on the ability of funding when they are determined to have the desired attenuating effect. Alberta Transportation is responsible for noise attenuation for provincial highways. As part of the future 65th Avenue Interchange Project, a sound barrier wall will be installed south of 65th Avenue on the east side of QEII.
Other noise fences were installed in the city in conjunction with road widening projects where the noise levels were below 65 decibels but projected to exceed those levels over the next 25 years. As a result, a noise fence was recommended and was installed while maintaining corridor aesthetics.