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

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

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

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

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

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

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

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

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

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

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 30 - 35 day and night Transportation Planning Lecture note

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

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

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

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

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

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

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

Noise Barriers Vertical Barrier Transportation Planning Lecture note

Noise Barriers Cantilever Barrier Transportation Planning Lecture note

Noise Barriers’ Transmission Loss Transportation Planning Lecture note

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. ‎

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

Noise Enclosure Semi-Enclosure Transportation Planning Lecture note

Noise Enclosure Full Enclosure Transportation Planning Lecture note

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

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

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

Decking Over Transportation Planning Lecture note

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

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

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

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

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

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

Plant Buffer Transportation Planning Lecture note

Plant Buffer Transportation Planning Lecture note

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

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

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

Effect of Noise Mitigation Measures Transportation Planning Lecture note

Effect of Noise Mitigation Measures Transportation Planning Lecture note

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

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

Transportation Planning Lecture note Finish