CE 341 Transportation CE 341 Transportation PlanningPlanning

Environmental Impact of Environmental Impact of Transportation ProjectsTransportation Projects

Environmental Impact of Environmental Impact of Transportation ProjectsTransportation Projects

Governmental regulations require an Governmental regulations require an environmental impact Assessment (EIA). The EIA environmental impact Assessment (EIA). The EIA must includes studies of the environmental, social must includes studies of the environmental, social and economic impact of the proposed projects.and economic impact of the proposed projects.

Many components of EIA studies fall beyond the Many components of EIA studies fall beyond the usual practice of transportation and traffic usual practice of transportation and traffic engineers and should be engineers and should be conducted by a specialistconducted by a specialist in the specific area.in the specific area.

EIA DEFINITIONEIA DEFINITION- - EarlyEarly at the design phase of Projects. at the design phase of Projects.

-Typical Projects Requiring EIA are :Typical Projects Requiring EIA are :

Waste management & disposal (solid, medical)Waste management & disposal (solid, medical)

Infrastructure (roads, highways, tunnels, bridgesInfrastructure (roads, highways, tunnels, bridges))

Water supply & irrigation (dams, canals, lakes)Water supply & irrigation (dams, canals, lakes)

Wastewater collection & disposalWastewater collection & disposal

Exploitation of natural resources (quarries, mines)Exploitation of natural resources (quarries, mines)

Coastal zone developments and Industrial activitiesCoastal zone developments and Industrial activities

EIA Content EIA Content A comprehensive EIA on a -large project may A comprehensive EIA on a -large project may

include the following: include the following: -Natural resources -Natural resources -Relocation of individuals and families -Relocation of individuals and families -Air quality studies-Air quality studies-Noise impacts-Noise impacts-Wet lands and coastal zones-Wet lands and coastal zones-Water quality issues-Water quality issues-Flood hazard studies-Flood hazard studies-Social and economic impact -Social and economic impact -Construction effects-Construction effects

EIA EVOLUTIONEIA EVOLUTION

Early 1970s :Early 1970s : initial developmentinitial development

•• 1970s to 1980s: trend to integration 1970s to 1980s: trend to integration

•• Mid to late 1980s: cumulative effects & Mid to late 1980s: cumulative effects & policy integration policy integration

•• Mid 1990s: Mid 1990s: towards sustainabilitytowards sustainability

(Strategic Environmental Assessment(Strategic Environmental Assessment))World Bank, Arab and other international World Bank, Arab and other international

funding agencies introduce EIA policies funding agencies introduce EIA policies within loan agreements.within loan agreements.

Noise Impact StudiesNoise Impact Studies

Determine the additional noise generated by the Determine the additional noise generated by the use of transportation systems in the community. use of transportation systems in the community.

The characteristics of environmental noise that are The characteristics of environmental noise that are of particular concern are :of particular concern are :

Magnitude of the sound Magnitude of the sound Frequency of the soundFrequency of the sound Temporal distribution of the soundTemporal distribution of the sound Time variance of the soundTime variance of the sound

IntensityIntensity

Intensity decreases inversely as the square Intensity decreases inversely as the square of the distance from a point source of the distance from a point source generating a fixed powergenerating a fixed power

24 r

WI

Noise Level Noise Level

Noise: undesirable or unwanted Noise: undesirable or unwanted soundsound

Level measurement: decibel Level measurement: decibel

dBI

IL

o

log10

Temporal Distribution and Time VarianceTemporal Distribution and Time Variance

- L50 is the sound level exceeded 50%of the L50 is the sound level exceeded 50%of the time (i.e.,the median sound level ).time (i.e.,the median sound level ).

- L10 level is the sound level exceeded 10 % - L10 level is the sound level exceeded 10 % of the time.of the time.

Design Standards for Noise LevelsDesign Standards for Noise Levels

Land useLand use Design Noise Design Noise Level-L10Level-L10

Exterior or Exterior or InteriorInterior

Lands on which serenity and quiet Lands on which serenity and quiet are of extraordinary significance are of extraordinary significance

60 dB (A)60 dB (A) ExteriorExterior

Picnic areas, recreational, parks, Picnic areas, recreational, parks, residences, hotels, schools, residences, hotels, schools, hospitals, librarieshospitals, libraries

70 dB (A)70 dB (A) ExteriorExterior

Other developed lands, properties Other developed lands, properties and activitiesand activities

75 dB (A)75 dB (A) ExteriorExterior

Undeveloped landUndeveloped land No limitNo limit ------------

Residences, hotels, meeting Residences, hotels, meeting rooms, schools, libraries, hospitalsrooms, schools, libraries, hospitals

55 dB (A)55 dB (A) InteriorInterior

Ambient Noise LevelsAmbient Noise Levels Ambient noise is the total noise composed of all Ambient noise is the total noise composed of all

natural and human –made noise sources considered natural and human –made noise sources considered as part of the acoustical environment of the general as part of the acoustical environment of the general area area

Ambient measurement times should coincide with Ambient measurement times should coincide with peak-hour traffic volumes for key sites. Under some peak-hour traffic volumes for key sites. Under some circumstances a 24-hour study period may be circumstances a 24-hour study period may be desirable.desirable.

Noise can be measured directly using a sound level Noise can be measured directly using a sound level meter (SLM) or with a tape recorder and statistical meter (SLM) or with a tape recorder and statistical analyzer. analyzer.

The noise source for automobiles and light trucks is The noise source for automobiles and light trucks is considered to be at ground level because the primary considered to be at ground level because the primary radiated noise comes from the tires and pavement. radiated noise comes from the tires and pavement.

Mitigation MeasuresMitigation Measures

From the contour lines, noise- sensitive locations From the contour lines, noise- sensitive locations can be identified. Especially critical noise- can be identified. Especially critical noise- sensitive sites sensitive sites such as schools, hospitalssuch as schools, hospitals, and , and social welfare must be identified for ambient social welfare must be identified for ambient measurements. measurements.

Possible mitigation options include changes in Possible mitigation options include changes in location (realignment) and geometry (gradient, location (realignment) and geometry (gradient, elevation, tunnel) and the use of road-side barriers elevation, tunnel) and the use of road-side barriers (walls, trees, or other shielding techniques, (walls, trees, or other shielding techniques, pavement (smoother aggregates).pavement (smoother aggregates).

Measures to Reduce NoiseMeasures to Reduce Noise

Depressed HighwayDepressed Highway Noise BarriersNoise Barriers

AIR PollutionAIR Pollution

Major PollutantsMajor PollutantsThe major direct pollutant species present in The major direct pollutant species present in

emissions are: emissions are: 1- Carbon monoxide (CO): a product of incomplete 1- Carbon monoxide (CO): a product of incomplete

burning of fuel. burning of fuel. 2- Hydrocarbons (HC): incomplete burning or 2- Hydrocarbons (HC): incomplete burning or

evaporated fuel or solvents, produced by mobile evaporated fuel or solvents, produced by mobile sources. sources.

3- Nitrogen oxides3- Nitrogen oxides (NO (NOxx): ): products of high-products of high-compression internal combustion engines.compression internal combustion engines.

4- Sulfur oxides4- Sulfur oxides (SO (SOxx): ): product of the burning of sulfur- product of the burning of sulfur- rich fossil fuel, particularly coal with minor emissions rich fossil fuel, particularly coal with minor emissions from motor vehicles.from motor vehicles.

5- Particulates: mostly carbon particles much like soot.5- Particulates: mostly carbon particles much like soot.6- Lead: the result of burning leaded gasoline.6- Lead: the result of burning leaded gasoline.

Measuring Emissions: Example from TehranMeasuring Emissions: Example from Tehran

Automobile Emission Characteristics.Automobile Emission Characteristics. The nature and concentration of those emissions The nature and concentration of those emissions

vary with:vary with:- type of enginetype of engine - mode of operation- mode of operation- fuel compositionfuel composition - atmospheric conditions- atmospheric conditions- presence and working condition of emission control presence and working condition of emission control

devices, anddevices, and- engine tuning. engine tuning. The mode of operation determines the air \fuel ratio, The mode of operation determines the air \fuel ratio,

which is a key factor determining the rate of which is a key factor determining the rate of emission output . emission output .

The completeness of combustion, which also affects The completeness of combustion, which also affects emissions, is relatively low when decelerating and emissions, is relatively low when decelerating and idling.idling.

Air Quality Impact StudiesAir Quality Impact StudiesCommonly conducted analysis for highway or an airport Commonly conducted analysis for highway or an airport

projects. The Steps are:projects. The Steps are:1-Projecting the amount of traffic expected to result 1-Projecting the amount of traffic expected to result

from the project.from the project.2- Calculating the quantity of pollutants that will be 2- Calculating the quantity of pollutants that will be

emitted by the project traffic.emitted by the project traffic.3-Estimating the resultant concentration of the 3-Estimating the resultant concentration of the

pollutants of interest for a particular receptor site, pollutants of interest for a particular receptor site, using a dispersion model or some other analysis tool using a dispersion model or some other analysis tool

4-Adding the traffic- generated pollutant concentration 4-Adding the traffic- generated pollutant concentration to an expected back-ground concentration generated to an expected back-ground concentration generated by other pollutant sources.by other pollutant sources.

5-Comparing the results to the ambient standard for 5-Comparing the results to the ambient standard for various alternatives.various alternatives.

Natural Resources EndangeredNatural Resources Endangered Ground waterGround water Green cover and forestsGreen cover and forests

Mitigation MeasuresMitigation Measures Slope stabilization to Slope stabilization to

protect buildingsprotect buildings Slope plantingSlope planting Deserted unused areasDeserted unused areas

Water Courses Water Courses

AestheticsAesthetics

Pedestrians bridgePedestrians bridge BridgesBridges

GuardrailGuardrail Noise breakerNoise breaker

Mitigation Measures: Retaining WallsMitigation Measures: Retaining Walls