There are several factors which influence vibration arising from road traffic at nearby houses. These include the following:
Distance from road to house: Vibration levels decrease with distance from the road. Although it is unlikely, vibration levels may occasionally exceed annoyance criteria when a house is located within 20m of the active carriageway of a road. At distances greater than 20m it becomes increasingly less likely annoyance criteria will be exceeded.
Condition of road surface: In most cases where significant vibration is identified, the cause is a defect in the road surface, such as a pothole, rutting, or a poor transition to a manhole cover.
Traffic conditions: Road traffic vibration is related to traffic volume (number of vehicles travelling a road per day will affect frequency of occurrence), traffic speed (vibration is proportional to speed), and the number of heavy vehicles using a road.
Presence of underground services/utilities: In some case vibration might travel farther distances from a road or occur at higher levels if underground services are poorly constructed (generally poor backfilling of a trench), and/or if services such as waterlines or drains, are leaking causing deterioration of trench backfill.
Ground conditions: The magnitude of vibration and the distance vibration levels are felt can depend on the both the soil type and the stratification of soil. Vibration travels farther in hard/stiff soils than in loose/soft soils. Vibration can also travel ‘preferentially’ in hard/stiff layers of soil.
House foundation/construction type and condition: The type and condition of house foundation can influence vibration levels felt inside. Vibration is more likely to be felt in houses with foundations in poor condition, foundations with ‘rigid’ connections between the ground and the house, and/or with significant surface area contact between the ground and the foundation. House construction can also influence the vibration levels felt inside, such as whether there is a timber or concrete floor.
Road pavement condition: In some cases, road pavements (the engineered soil layer provided beneath the road surface to allow for a stable and smooth road surface) deteriorate over time causing defects in the road surface that might cause vibration issues. Occasionally, pavements in poor condition may also directly induce vibration in near surface soils that can be felt at nearby houses.