For instance, on the supply side, traffic flow, speed, composition, frequency of stopping and starting, road gradient and surface. When considering the affected side, the factors like proximity to road, type of land use and time of day, also affect the generation of traffic noise. 1. 2 Purpose of the Study The main purpose of the study is to assess and find out the variations in traffic noise level under Stop-Go situations. 1. 3 Objectives of the Study The objectives of this study are: * To determine the level of noise due to vehicle Start. * To determine the level of noise due to vehicle Stop.
To assess variations in traffic nose level under Stop-Go situations. 1. Study Area The study area is an intersection where is located along Persian Tama road. The intersection is signaled and it is located at Saudi Town. Saudi Town is located within the Juror Barr District and it is between the Sinai and Juror Barr City Centre. It is under administrative of Juror Barr Central Municipal Council. Figure 1-1 shows the location Of study area. Figure 1 ;1: Study Area. 1. 5 Scope of the Study The scope of this study is mainly focused on the assessment level of noise under Stop-Go situations.
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The study area is intersection where is tied Persian Tama road with Persian Tama 1 road. The collected data are Noise level. The instrument that has been used to collect data is a survey. CHAPTER 2 LITERATURE REVIEW 2. 1 Introduction Stop-and-Go or more generally interrupted traffic is one of traffic phenomena being controlled by traffic signals at intersections. The prediction of traffic noise level in such the area needs the characteristic of traffic flow in conjunction with noise emission level of each vehicle type.
The movement characteristic of traffic at an intersection can be forecasted using traffic flow horses whereas noise emission level is obtained from field measurement data. This study aiming at the collection of stop and go noise emission level which indeed relates to the level of noise pollution received by student and teacher at Seakale Meghan Sebastian Minutia Rind. As the school is located at a busy intersection, noise pollution in the school environment is expected to disturb the activities in school such as study, discussion and teaching session.
Therefore, the environmental assessment of traffic noise at intersections near the school is measured. 2. Noise 2. 2. 1 Definition of Noise people who study acoustics define noise as complex sound waves that are periodic, in other words, sound waves with irregular vibrations and no definite pitch. In engineering, noise is defined as a signal that interferes with the detection of or quality of another signal. In fact, it is difficult to recognize the noise sound from others. For Instance, Is music noise?
Is the hum of tires on a highway noise? Is the surround-sound movie theater noise? Is the philharmonic concert noise? And what about the accompanying beat for aerobic exercises at the health club? Sounds that are soothing for some are irritating to others. Basically, noise is unwanted sound. It is a pollutant and a hazard to human health and hearing. Noise is one of the environmental pollutants which create interference in communication and health (Augural and swami 2009; Pratt and Nagasaki 2007; Apathy et al. AAA).
It an environmental stress which has received much attention in the past (Zinnia et al. 2006). The World Health Organization (WHO) considered noise as the third most hazardous type of pollution right after air and water pollutions (WHO 2005). People exposed to high-level noise may be affected in en or more of three ways: health, performance, and comfort (Media and Outshone 2001). Research regarding urban noise pollution and its consequences for the community has been studied by several countries (Apathy et al. Bibb; Kumar and Gain 1998; All 2004 Oshkosh et al. 1999). The most obvious effect of noise is damage to hearing ability, which may be temporary or permanent depending on the exposure time (Immemorial al. 2002;Hyssop and Aisha 2005). Similar study that focused on the behavior of human beings exposed to traffic noise was carried out in Canada by Michael et al. (2008). Generally, motor vehicles, which are a very significant part Of the urban environment, are an important source of noise emission, contributing 55% to the total noise (Bannered et al. 008; Naira et al. 2003). 2. 2. 2 Unit of Noise Noise levels are measured in decibels (db). The higher the decibel level, the louder the noise. The decibel (db) is a logarithmic unit for the ratio of a physical quantity, usually power or intensity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities. Being a ratio of two measurements of a hysterical quantity in the same units, it is a dimensionless unit. A decibel is one tenth of a bell, a seldom-used unit.
The decibel is widely known as a measure of sound pressure level, but is also used for a wide variety of other measurements in science and engineering, most prominently in acoustics, electronics, and control theory. In electronics, the gain of amplifiers, attenuation of signals, and signal to noise ratios are often expressed in decibels. It confers a number of advantages, such as the ability to conveniently represent very large or small numbers, a logarithmic scaling hat roughly corresponds to the human perception of sound and light, and the ability to carry out multiplication of ratios by simple addition and subtraction. . 2. 3 Noise Measurement Unit used to measure sound pressure level is decibel (db). Sound can also measured using Pascal (Pa) but measurement in Pascal would therefore quite unmanageable numbers. The decibel scale is simple and easy to use without involving long linear numbers. Decibel also gives a much better approximation of the response of human ear to loudness. With every unit of decibel it must be included a weighting network at the end of it. This weighting network used to differentiate sound based on its frequency.
There are three categories of weighting system that is always used, that is A,B and C. The difference between weighting network between ABA and C are A discriminates against the low frequencies. 8 also discriminates against the low frequencies but to a lesser extent, and C to the least extent. There is also a D weighting but it is used to measure noise from airplanes. In this study, the weighting network of A will be used because its characteristic is almost the same as characteristics of human ear. Instrument used to measure noise bevel at source is sound level meter.
The unit used in this instrument is decibel. Sound level meter is design to react with sound is similar to reaction with human ear. The difference is that the sound measured by this instrument will be processed and changed into numbers for interpretation purposes. Sound level meter consist of microphone, amplifier, network weighting (A,B, and C) and a meter. Microphone is an important part of the instrument. The sound will enter the sound level meter through microphone and the acoustic energy of sound will be transferred into electric signal by microphone.
After all the transformations have been completed the meter will process the input data in decibel values. 2. 3 Classification of the Noise Levels Both the amount of noise and the length of time you are exposed to the noise determine its ability to damage your hearing. Noise levels are measured in decibels (db). The higher the decibel level, the louder the noise. Sounds louder than 80 decibels are considered potentially hazardous. The noise figure below gives an idea of average decibel levels for everyday sounds around you.
Painful 150 db rock music peak 140 db = firearms, air raid siren, jet engine 30 db = jackhammer 120 db jet plane take-off, amplified rock music at 4-6 Ft. , car stereo, band practice Extremely Loud 110 db = rock music, model airplane 1 06 db = timpani and bass drum rolls 1 00 db = snowmobile, chain saw, pneumatic drill 90 db = lawnmower, shop tools, truck traffic, subway Very Loud 80 db = alarm clock, busy street 70 db busy traffic, vacuum cleaner 60 db = conversation, dishwasher Moderate 50 db = moderate rainfall 40 db = quiet room Faint 30 db = whish per, quiet library 2. Noise Pollution at School Environment Schools’ surrounding are the place that is considered as noise abatement zone. School environment especially located in busy area has a high rate of noise pollution. There are many new schools built near roadways in residential areas without noticing the impact of traffic activities to the school environment. Noise pollution at school environment is due to many sources. It depends on where the school is built. A school which is located near the city center has a very high noise pollution range because it has many sources that will lead to noise pollution.
In this study area, Seakale Meghan Sebastian Minutia Rind which is located at intersection with traffic signal has the potential of Ewing noise polluted as the intersection normally congested during peak hour with many types of vehicle pass through the road. Noise from vehicles especially motorcycle, buses and trucks are very annoying and disturbing. 2. 4. 1 Effect of Noise Research being done by Snobbery (1 974), he has determine some effects of noise pollution to school students , such as : 1. They did not hear the teacher as well 2.
They found it more difficult to hear lectures and classroom discussion 3. It was more difficult to study 4. They felt it was necessary to talk loudly in class in order to be heard 5. Some teachers have to speak too loudly and 6. Outside noise bothered them Much of the research on noise and children concerns damage to the auditory system. While the possibility of hearing damage is, and should be, of concern to parents and educators, the non-auditory effects of noise on children also deserves attention.
The literature on the latter topic falls into three categories; physiological effects, motivational effects, and cognitive effects. 2. 4. 1. 1 Physiological effects An elevated blood pressure level in school-aged children is associated with living or going to school near a major noise source (e. . , Stop and go, traffic light, trains). Although the blood pressure levels of children exposed to these major noise sources are within the normal range, they are higher than for children not exposed to major noise sources. Refereed to the previous statistic, the elevated blood pressure levels are of concern for two reasons.
One, the levels do not habituate with continued exposure, and two, elevated pressure levels in children appear to continue this pattern into adulthood thereby increasing the risk for cardiovascular disease. In each case the noise exposure was chronic. 2. 4. 1. 2 Motivational effects Research findings suggest that exposure to uncontrollable noise may make children more vulnerable to learned helplessness. Learned helplessness means that the individual learns that the outcomes of its behavior are independent of the actions of the individual. Most of this research has been with school-aged children, including kinderg??rtners.
One study found that children attending a school near a major airport were less likely to solve a challenging puzzle and to persist at it as well. Another study found that children exposed to noise were more likely to abdicate their choice for a reward to their teachers. The children decided to let the adult pick a prize for them rather than exercise their option to do so. Teachers in noisy schools also report greater difficulty in motivating children in their school work. Children often had less tolerance for frustration. Limited work has been done with younger children.
One study in a residential setting found that 12 month- old infants in noisy homes exhibited less mastery-oriented play behavior with their toys than their counterparts in quieter homes. 2. 4. 1. 3 Cognitive effects Most of the research on the non-auditory effects of noise on children has been on cognitive effects. The research has looked at memory, attention/ perception, and academic achievement. The study on memory and noise for children parallels that of adults; there appears to be little or no effects of noise on simple memory. This holds true for both chronic and acute exposure to noise.
However, if the memory task requires special attention there does appear to be some negative effects of noise. In other words, if the individual has to pay particular attention because of the difficulty of the task, noise may interfere with the memory task. 2. 4. 2 Ways to Reduce Noise Problem in School’s Environment Research done by Slater (1968) proved that student will perform better under quiet condition than noisy condition. Noise pollution in school environment disturbs during study session. Students cannot concentrate with what they are learning and consequently they will lose their interest to study. Searchers also cannot teach effectively during teaching session. This is due to uncomfortable classrooms conditions that the students cannot hear their voice clearly and the student will hardly understand what the teacher is trying to teach. There are many ways to reduce noise pollution problem from getting worst specially in school environment : 1. Construct a school building that has sound insulation system 2. Construct sound barrier such as high fence made from concrete wall of wood 3. Planting more trees in the school’s surrounding 4. A good planning before building school 5.
Stop or remove the noise 6. Society awareness about the noise problem 7. A strict laws concerning noise pollution and 8. Speed limit for road users near school surrounding 2. 5 Characteristics of Noise Waves Noise or sound is created by alternate compression and decompression of particles of the air. This causes the air pressure to fall and rise in the form of waves. Frequency (pitch) and intensity (loudness) are the two characteristics of sound. 2. 5-1 Frequency Frequency is the number of times that the air is compressed and decompressed in a second, and is measured in cycles per second, or Hertz (Haze).
Low frequency produces a low pitched, bass sound. High frequency produces a high pitched, whistle sound. Human ears respond to frequencies between GHz and 20,GHz. The human voice produces frequencies between GHZ and 2,OOZE. Below GHZ and above 20,000 HAZE sound cannot be heard but it can still be harmful. The ear is most sensitive to sounds between 1000 and GHz. 2. 5. 2 Intensity Intensity is the amount of sound energy reaching the eardrum, and is measured in decibels (db). Zero decibels is the faintest sound that the average person can hear, and the loudest sound may be more than a million times this level.
This is because the intensity of sound does not rise gradually – each increase of 10 decibels means that the intensity increases 1 0 times. For example, a 10 decibel sound is 10 times louder than a 1 decibel sound; a 20 decibel sound is 100 times louder than a 1 decibel sound (xx); 30 Seibel are 1000 times louder (10x10x10), and so on. The ear responds to intensities from O to db. Discomfort is felt at db, and near db, pain is felt with possible rupture and permanent damage to the eardrum.
Some noise intensity measurements are given in a measure called ‘db(A)’ which takes into account the frequency sensitivity of the ear. db(A) measurements are obtained on a noise meter which weights the different frequency components. For example, the noise intensity for a circular saw, and the noise intensity inside a bus have the same value when expressed in db. But the noise from a circular saw contains a greater proportion of high frequencies, and is more annoying than the noise inside a bus. Therefore, the circular saw has a higher db(A) value. 2. Main Traffic Noise Sources Noise sources associated with transportation projects can include passenger vehicles, medium trucks, heavy trucks and buses. Each of these vehicles produces noise; however, the source and magnitude of the noise can vary greatly depending on vehicle type. For example, while the nose from passenger vehicles occurs mainly from the tire-roadway interface and is Hereford located at ground level, noise from heavy trucks is produced by a combination of noise from tires, engine, and exhaust, resulting in a noise source that is approximately 8 feet above the ground.
The following list provides information on the types of transportation noise sources that will be part of a roadway project, and describes the type of noise each produces. 2. 6. 1 Passenger Vehicles (cars): Noise emitted from O to 2 feet above roadway, primarily from tire-roadway interface. This category includes normal passenger vehicles, small and irregularities trucks, small to mid-size sport utility vehicles, mini- and full-size assenter vans. Typical noise levels for passenger vehicles are 72 to 74 dab at 55 MPH at a distance of feet. 2. 6. Medium Trucks (MET): Noise emitted from 2 to 5 feet above roadway, combined noise from tire- roadway interface and engine exhaust noise. This category includes delivery vans, such UPS and Federal Express trucks, large sport utility vehicles with knobby tires, large dieseling trucks, some tow-trucks, city transit and school buses with under vehicle exhaust,moving vans (U-haul-type trucks), small to medium recreational motor homes and turbocharger trucks with the exhaust located under the vehicle. Typical noise levels for mediumistic are 80 to 82 dab at 55 MPH at 50 feet. . 6. 3 Heavy Trucks (H T): Noise emitted from 6 to 8 feet above the roadway surface, combined noise sources includes tire-roadway interface, engine noise, and exhaust stack noise. This category includes all log-haul tractor-trailers (semi-trucks), large tow trucks, dump trucks, cement mixers, large transit buses, motor homes with exhaust located at top of vehicle, and other vehicles with the exhaust located above the vehicle (typical exhaust height of 12 10th feet). Typical Jose levels for heavy trucks are 84 to 86 dab at 55 MPH at 50 feet 2. 2. 6. Road Noise Arises from Three Sources on Vehicles: * propulsion noise (engine, power train, exhaust and intake systems) Tire/road contact noise * Aerodynamic noise The engine noise is the dominant source at lower speeds (under km/h for passenger cars / under km/h for lorries), tire noise dominates above that, and aerodynamic noise becomes louder as a function of the vehicle speed. 2. 7 Traffic Noise Mitigation In theory, there are a number of options that can be used to reduce or mitigate traffic noise. These include traffic management, highway design, and noise barriers including earthen beers.
In reality, noise mitigation is often infeasible due to space requirements, aesthetic issues and financial costs, or because the costs o;sigh the benefits. Any specific mitigation measure recommended as part of a project must be feasible and have a reasonable cost in relation to the benefit. Potential mitigation measures are described below. 2. 7. 1 Traffic Management Traffic management measures include modification Of speed limits and restricting or prohibiting truck traffic. Restricting truck use on a given roadway loud reduce noise levels at nearby receivers since trucks are louder than cars.