1. Noise Pollution Noise Mitigation
and
Noise Mitigation
Transportation Planning
Lecture note
Meeghat Habibian

2. Outline Introduction ‎Noise Pollution Effects Sound Properties
Noise Level Measurements
Acceptable Noise Level
Noise Mitigation
Roadway Noise Mitigation
Aircraft Noise Mitigation
Noise Reduction Level
Transportation Planning Lecture note

3. Introduction Noise Pollution
The disturbing or excessive noise that may harm the activity or balance of human or ‎animal life.‎
Transportation Planning Lecture note

4. Introduction: Trains Motor Vehicles Machines Aircrafts Outdoor Noise
Indoor Noise
Transportation Planning Lecture note
Machines
Music Performance
Building Activities

5. Noise Pollution Effects on Humans:
Cardiovascular effects
A rise in blood pressure
An increase in stress and vasoconstriction
An increased incidence of coronary artery disease
Transportation Planning Lecture note

6. Sound Properties Frequency (Vocal type) Sound intensity Sound identity
Speed of sound
Direction
Transportation Planning Lecture note

7. Noise Level Measurements
Factors Affecting Noise Assessment:
The absolute sound pressure level of the noise source and variations over time
Frequency of the noise
Duration of the noise
Sensitivity to noise
Site location and local land use
Activities underway when noise is audible
Transportation Planning Lecture note

8. Noise Level Measurements
Based on their presumed audibility to humans, some sound ‎frequencies are more important than others.‎
Weighting filters:‎
A-weighting filter
Abbreviated as dB(A) or dBA
commonly used to emphasize frequencies around 3–6 kHz where the human ear is most sensitive
B-, C-, and D-weighting filter
intended for louder sounds (less used)
Transportation Planning Lecture note

9. L=α+β log V+ γ log q+ δ log d
Noise Level Measurements
Determining noise level:
L=α+β log V+ γ log q+ δ log d
L = noise level (dBA)
V = mean speed of traffic (mile/h)
q = traffic flow (veh/h) q>1000 veh/h
d = distance between receptor and imaginary line of sound (ft)
Transportation Planning Lecture note
A calibrated form is:
𝐋=𝟐𝟎+𝟐𝟎 𝐥𝐨𝐠 𝐕+ 𝟏𝟎 𝐥𝐨𝐠 𝐪−𝟏𝟎 𝐥𝐨𝐠 𝐝 or
L=20 log 10V q d

10. Effective Parameters on Noise
An increase of 2.5% in trucks volume traffic, increases noise level by 1 dBA.
Corresponding to each 2.5% slope increase, noise level increases by 1 dBA (Max. 2 dBA).
To reduce the noise level more, appropriate noise barriers should be designed.
Transportation Planning Lecture note

11. Acceptable Noise Level
Maximum acceptable Equivalent Sound Level ( Leq )at some common locations:
Location
Effects
Max. Leq (dBA)
Time (h)
Time of day
Bedroom
sleep disturbance, annoyance 30 8
night
Living area
annoyance, speech interference 50 16
day
Outdoor living area
moderate annoyance
serious annoyance 55
sleep disturbance, with open windows 45
School classroom
speech interference, communication disturbance 35
Hospitals patient rooms
sleep disturbance, communication interference
day and night
Transportation Planning Lecture note

12. General Noise Mitigation Methods
Control at noise sources
Noise reduction at the transmission path
Protection at the receiver end
Transportation Planning Lecture note

13. Main Transportation Noise Sources
Noise Mitigation or Control
Set of strategies to reduce noise pollution or its impact
Main Transportation Noise Sources
Transportation Planning Lecture note
Aircrafts
Roadways

14. Aircraft Noise Mitigation
Using quieter jet engines
Land planning
Residential soundproofing
Flight operations restrictions
Preferred runway use
Preferred departure flight path and slope
Time-of-day restrictions
Transportation Planning Lecture note

15. Roadway Noise Mitigation
Noise Barriers
Noise Enclosure
Traffic Controls
Roadway Geometrical Design
Screening by Noise Tolerant Buildings
Decking Over
Podium
Surface Pavement Selection
Plant Buffers
Architectural Features/Balcony
Acoustic Insulation Of Receiver
Transportation Planning Lecture note

16. Noise Barriers
Also called: sound wall, sound berm, sound barrier, or acoustical barrier
Transportation Planning Lecture note

17. Noise Barriers:
The most effective method of mitigating roadway, railway, and industrial noise sources
Commonly can reduce adjacent land use sound levels by up to 10 decibels
Transportation Planning Lecture note

18. Noise Barriers:
Commonly constructed using: steel, concrete, masonry, wood, plastics, insulating wool, or composites
Constructed on private land, on a public right-of-way, or on other public land
A computer model is required to design the barrier since terrain, micrometeorology and other local factors make a complex situation
Transportation Planning Lecture note

19. Noise Barriers
Vertical Barrier
Transportation Planning Lecture note

20. Noise Barriers
Cantilever Barrier
Transportation Planning Lecture note

21. Noise Barriers’ Transmission Loss
Transportation Planning Lecture note

22. Noise Barriers
Disadvantages of noise barriers:
Certain locations and topographies are not suitable for use of any reasonable noise barrier
Costs of design, construction, and maintenance
Aesthetic impacts particularly if scenic vistas are blocked ‎
Transportation Planning Lecture note
Normally, the benefits of noise reduction far outweigh aesthetic impacts for residents protected from ‎unwanted sound. ‎

23. Noise Enclosure:
It can prevent the line-of-sight between the noise source and the receiver (especially for high-rise noise sensitive uses).
An enclosure can reduce noise by more than 20 dB(A).
Transportation Planning Lecture note

24. Noise Enclosure
Semi-Enclosure
Transportation Planning Lecture note

25. Noise Enclosure
Full Enclosure
Transportation Planning Lecture note

26. Traffic Controls
Speed control is effective since the lowest sound emissions arise in 30 to 60 km/h.
Above that range, sound emissions is doubled with each 5 mile/h of speed.
At the lowest speeds, braking and (engine) acceleration noise dominates.
Transportation Planning Lecture note

27. Roadway Geometrical Design
When designing new urban freeways or arterials, there are numerous design decisions ‎regarding alignment and roadway geometrics.
Transportation Planning Lecture note

28. Screening by Noise Tolerant Buildings
Using a noise tolerant building such as a multi-level car park building to protect residential buildings from road traffic noise.
Transportation Planning Lecture note

29. Decking Over
Transportation Planning Lecture note

30. Podium Putting residential buildings on top of a podium (platform)
Transportation Planning Lecture note

31. Surface Pavement Selection
Two main sources of noise from vehicles:
Engine
Road-tyre interaction.
Different material on the road will reduce the noise of road-tyre interaction.
Quieter pavements are porous and use medium to small aggregates.
Transportation Planning Lecture note

32. Surface Pavement Selection
The open-textured bituminous highway surfacing consists of tiny holes can reduce traffic noise, induced by road-tyre interaction.
Transportation Planning Lecture note

33. Plant Buffer
Locate buffer close to the noise source while providing an appropriate setback for accidents and drifting snow.
Evergreen species will offer year-around noise control.
Create a dense buffer with trees and shrubs to prevent gaps.
Transportation Planning Lecture note

34. Plant Buffer
Select appropriate plants (site, air pollution, de-icing methods, ...)
Natural buffers will be less effective than planted buffers because they are usually less dense.
Consider topography and use existing landforms as noise barriers where possible.
Transportation Planning Lecture note

35. Plant Buffer
A setback distance from the noise control buffer may be necessary to achieve the desired levels of noise reduction along a high speed road.
Transportation Planning Lecture note

36. Plant Buffer
Transportation Planning Lecture note

37. Plant Buffer
Transportation Planning Lecture note

38. Architectural Features/Balcony
Certain architectural features such as fins and balcony can help reduce impact of road traffic noise on residential buildings.
Transportation Planning Lecture note

39. Acoustic Insulation of Receiver
Window insulation and air-conditioning as the “last resort”.
Open window and close window reduces noise level by 10 dBA and 20 dBA respectively.
Transportation Planning Lecture note

40. Acoustic Insulation of Receiver
The window type that should be used when the estimated noise level will exceed the relevant standard by ß value.
Transportation Planning Lecture note

41. Effect of Noise Mitigation Measures
Transportation Planning Lecture note

42. Effect of Noise Mitigation Measures
Transportation Planning Lecture note

43. Example
24 ft D
200 ft
A house is located at 200 ft from a highway containing 3000vph traffic flow (In peak hour, truck percent= 5% and speed =50mph). What should be done to meet the living area standard for this house during the day?
Transportation Planning Lecture note
خانه

44. Example خانه Window and noise barrier Closed window and A/C …
Transportation Planning Lecture note
خانه

45. Transportation Planning Lecture note
Finish