Comparative Analysis of Environmental Impact of Vehicle Noise Sources in Samarkand and Tashkent

Noise pollution is one of the most significant challenges facing the world in modern times, as noise sources continue to increase due to industrial development and modern lifestyles [1]. There is an increase in noise pollution in cities, which is directly related to the increase in vehicles. The increase in traffic and the resulting traffic jams in the morning and evening, horns, as well as the movement of vehicles themselves significantly affect the health of the population. Technical and industrial enterprises are major contributors to this pollution, causing discomfort to people and negatively impacting their mental and physical health [2]. This issue also extends to the environment, affecting animals and plants. Furthermore, noise pollution is regarded as a critical environmental problem that necessitates preventive measures and solutions to control noise sources, strengthen environmental protection laws, and mitigate its consequences. Over the past few years, noise in urbanized areas has increasingly impacted human health, becoming a leading source of environmental pollution [3]. Along with a sharp increase in the pace of urbanization in the current period, the growing number of vehicles has made the problems of acoustic ecology relevant. Noise pollution is one of the most important environmental problems facing the world in modern times, as noise sources continue to increase due to industrial development and modern lifestyle. Technical and industrial enterprises contribute significantly to this pollution, causing discomfort to people and negatively affecting their mental and physical health [4]. Noise is recognized as an environmental risk that can cause serious harm to human health. Statistical monitoring in this regard is conducted regularly in developed countries such as the European Union, the United States and Japan. But in Uzbekistan, the field has not yet been sufficiently studied, there is no systematic database. As in many developing countries, the problem of noise pollution is relevant in two cities of Uzbekistan, such as Tashkent and Samarkand.

As an environmental factor, noise pollution has serious effects on people working in noisy conditions [5]. It can lead to hearing loss, headaches, reduced mental activity, various nervous system disorders (e.g., neurasthenia, neurosis, sensory impairments), peripheral nervous system diseases, exacerbation of cardiovascular issues, high blood pressure, noise-induced stress, fatigue, sleep disorders, impaired attention, and decreased labor productivity [6]. Physiological changes in the body often accompany these conditions. Therefore, it is crucial to implement preventive measures to address this issue and reduce noise pollution sources.

Noise significantly degrades the living environment in large cities [7]. A substantial portion of environmental acoustic pollution (70-90%) is attributed to road transport [8]. A distinctive feature of this type of noise is its non-periodic nature–its levels rise and fall abruptly, varying greatly in duration. The intensity of these noises often exceeds the threshold of human sensitivity, posing serious risks to health and well-being [9, 10].

The problem of noise pollution in Uzbekistan, as in many developing countries, is urgent. The main sources of noise are motor transport, industry, construction and household sources. An increase in the number of cars, an outdated fleet (many vehicles do not meet modern noise standards), poor roads and non-compliance with traffic regulations contribute to high noise levels. Businesses, especially those located near residential areas, can be a significant source of noise. Construction works, especially in densely populated areas, create a significant background noise. As well as noise from neighbors, loud music, and household appliances contribute to noise pollution.

The city of Samarkand is one of the ten most densely populated districts and cities of the Republic of Uzbekistan. As of 02/05/2025, the population of the city of Samarkand is 595.8 thousand people. The population of Tashkent city was 3,112.8 thousand people as of 01.01.2025. Among the regions, the largest number of vehicles was registered in the city of Tashkent (624,022 units), as well as in Samarkand (448,702 units). According to the statistical agency, as of January 1, 2024, according to the results of the technical inspection. These regions account for 37.6% of the total number of cars owned by the population in the Republic of Uzbekistan. Of these, the number of passenger cars amounted to 3,759 thousand units, trucks-240.9 thousand units, buses-6.3 thousand units, minibuses-9.1 thousand units, special vehicles-5.4 thousand units. The increased content of vehicles in two cities of Uzbekistan, Tashkent and Samarkand, prompted us to study possible noise pollution in these two cities and calculate the correlation between noise pollution and the number of vehicles.

Tashkent has the largest number of industrial enterprises in the country. According to the Agency for Statistics, as of February 1, 2024, a total of 68,691 industrial enterprises are operating in Uzbekistan. Most of them are concentrated in Tashkent–11,930. Ferghana region is in second place with 7,635. The Tashkent region closes the top three with 7,273, and the Samarkand region is in fourth place, with 6,065 operating industrial enterprises [11]. Since the main noise pollutants in the form of vehicles and industrial enterprises are concentrated in these two cities, we were tasked to study the noise data in these two cities and compare them to understand how much noise pollution is observed in these most densely populated cities of Uzbekistan. For the first time in Uzbekistan, traffic noise pollution of two large cities with different urbanistic conditions was compared on a scientific basis. Tashkent is the capital of Uzbekistan and the most densely populated megapolis (3.1 million people), with centralized industrial and transport systems. Samarkand is a historical and tourist center with an average level of urbanization (595 thousand people), but in recent years the number of cars has increased sharply (448 thousand cars). Tashkent has a high volume of daily car traffic; there are many industrial districts and tracks. In Samarkand, however, the roads are narrower, with a different distribution of traffic flow due to historical architecture. This directly affects the propagation and reflection of noise. If there are wide streets, high-rise buildings and modern transport routes in Tashkent; And in Samarkand, most of the urban part is represented by ancient, narrow streets and low-rise houses. Such infrastructure increases the reverberation of noise. Samarkand and Tashkent were selected for comparison due to their contrasting urban characteristics. Tashkent, as a highly urbanized capital, exhibits dense road networks, industrial zones, and intense vehicle circulation. In contrast, Samarkand features narrower streets, historical infrastructure, and moderate urban sprawl. Comparing these two cities allows a deeper understanding of how different urban environments influence traffic-related noise pollution.

According to the State Statistical Agency of the Republic of Uzbekistan on January 1, 2024: there are 3,759 million cars, 240,900 trucks, 6,300 buses, 9,100 minibuses, 5,400 special equipment, 37.6% of which belongs only to Tashkent and Samarkand. In Uzbekistan, vehicular traffic has increased dramatically in recent years, with over 4 million vehicles currently registered and over a third concentrated in just two urban centers-Tashkent and Samarkand. Despite this, there is no national-level noise monitoring network, no centralized public noise database, and no comprehensive urban acoustic mapping strategy. This results in fragmented data, limited public awareness, and a lack of evidence-based policy development. Unfortunately, there is insufficient systematic data on noise pollution in Uzbekistan. In Uzbekistan, official noise monitoring is still underdeveloped. There is no single continuous acoustic monitoring system. According to regional environmental services, in Tashkent and other large cities, noise levels often exceed 60-70 dB near busy roads, while according to regulations, levels up to 55 dB during the day and 45 dB at night are considered acceptable for residential areas. In some areas, the noise level reaches 80 dB or higher, which is comparable to the noise of a motorcycle or heavy street traffic and can cause harm to health if exposed for a long time. This study aims to fill that gap by providing structured comparative measurements of traffic noise in the country’s two most impacted cities. There are no extensive, regularly updated databases comparable to those of developed countries. This makes it difficult to accurately assess the problem and develop effective measures to address it. To solve these problems, noise measurements were carried out in this study in correlation with the number of vehicles. There are no systematic and complex noise studies in Uzbekistan. Existing research on noise pollution in Uzbek cities is limited to local, narrow-range facilities (e.g.: one street or one school suburb). No study has calculated a statistical correlation between traffic density and noise Leq levels based on inter-city comparison (inter-city comparison). This study directly addresses the current lack of comparative, statistically grounded noise pollution data across major Uzbek cities. By measuring real-time noise levels at systematically selected sites in Samarkand and Tashkent and correlating them with traffic intensity, the study fills a gap in urban environmental monitoring and provides a foundational dataset for future acoustic planning in Central Asia.

Recent studies have emphasized the growing challenges of traffic-related noise in transitional urban contexts. For example, Fallah-Shorshani et al. [12] investigated how Tehran’s dense road networks affect Leq values during peak hours, while Danilevičius et al. [13] correlated heavy vehicle density with noise levels in Lithuanian cities. These methodologies, particularly the use of Pearson correlation and short-term measurement intervals, align with our approach. However, Central Asian urban contexts-such as Samarkand and Tashkent-remain underrepresented in this field. This study aims to bridge that gap.

The measurements were conducted at 8 locations in the city of Samarkand and on 4 main roadways in the capital, Tashkent, to perform a comparative analysis. In Samarkand, measurements were taken at the following locations: University Avenue, Registan Square, Boaston Saroy Street, Registan Street, Rudakiy Street near Siyab Bazar, the Rudakiy Street tram pass, Mirzo Ulugbek Street (Gum), and University Avenue near Namazgoh Street, as well as Ja’mi Street.

The noise levels measured on these streets were found to exceed the standard levels. Other factors influencing the intensity of traffic noise, such as vehicle speed, the nature of the noise source (e.g., acceleration or braking), road conditions, traffic composition, and the presence of intersections, also need to be considered when assessing traffic noise in the urban area.

During a 2-minute noise measurement on the selected streets, it was observed that, compared to other streets, Rudakiy Street (South Market) had 308 vehicles, with a maximum noise level of 84 dB and an average equivalent sound level (Leq) of 73 dB. On Mirzo Ulugbek Street (Gum), 248 vehicles were recorded, with a maximum noise level of 79 dB and an average (Leq) of 71 dB.

In residential areas, public buildings, and recreational areas, the permissible noise level was measured based on the equivalent sound pressure level by octaves, considering day and night time. It was found that the noise level exceeded the permissible limits specified in paragraph 9 of the sanitary rules (Figure 3).

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Figure 3. Noise sources and their levels on road transport at 8 points in the city of Samarkand

The noise level from vehicles is greatly influenced by factors such as road condition, the volume of traffic (i.e., how many vehicles pass in one direction within an hour), the width of the road, and the presence of greenery along the road. The unevenness of the road and the construction of multi-story buildings along narrow streets also contribute to increased noise intensity. Noise measurements in residential areas cannot be conducted during rain or when strong winds are present. If the wind speed exceeds 1 meter per second, the microphone is shielded with a screen to protect it from the wind.

The result of the correlation between the number of cars and noise in Samarkand is 0.635. This suggests that there is a moderately positive relationship between the number of cars and the noise level in Samarkand. This means that as the number of cars in Samarkand increases, the noise level also increases. Conversely, reducing the number of cars is likely to lead to lower noise levels. However, it is not absolutely strict or linear. In other words, changing the number of cars does not explain all the changes in noise levels, and other factors also affect noise levels.

Additional factors affecting noise (besides the number of cars) [17]:

Type of car: Trucks and buses usually produce more noise than passenger cars.

Technical condition of vehicles: Faulty vehicles (for example, with a faulty exhaust system) may produce more noise.

Driving style: Aggressive driving (sudden acceleration, braking, using a sound signal) increases the noise level.

Road conditions: Poor roads (with potholes and cracks) increase the noise level.

Driving speed: Higher driving speed increases the noise level.

Building density: Narrow streets with dense buildings can increase noise.

Time of day: The noise level is usually higher during peak hours.

Other sources of noise include industry, construction, public transport, and musical events.

For the comparative analysis, streets in the capital were selected, and noise measurements were conducted on the following streets: Farobiy Street (near Beruniy station), Beruniy Street (Chorsu hotel), Sharof Rashidov Street (Independence Square), and Samarkand Gate. During the 2-minute measurement period on each selected street, the number of vehicles and noise levels were recorded. On Beruniy Street (Chorsu hotel), there were 252 vehicles, with a maximum noise level of 99 dB (due to traffic) and an average (Leq) of 85 dB. On Farobiy Street (near Beruniy station), 290 vehicles were recorded, with a maximum noise level of 94.8 dB and an average (Leq) of 86 dB. The results were calculated and are shown in Figure 4.

The correlation result of 0.97 between the number of cars and the noise level in Tashkent indicates a very strong positive relationship. This means that as the number of cars in Tashkent increases, the noise level also increases significantly. Conversely, reducing the number of cars is likely to lead to a significant reduction in noise levels. The value of 0.97 is close to +1, which indicates a very strong linear relationship between the variables. This means that the number of cars is a very good predictor of the noise level in Tashkent. Most of the changes in noise levels can be explained by changes in the number of cars. Knowing the number of cars, it is possible to predict the noise level with high accuracy, and vice versa. This strong relationship highlights the need to take measures to regulate automobile traffic in Tashkent to reduce noise pollution. Urban density high: in Tashkent, the traffic flow is high, multi-storey buildings are located close to the road-this leads to the accumulation and reflection of noise. Width of tracks and junction of tracks: Here the traffic flow is stagnant and dense, and there is less variability, i.e., Leq levels are more smoothly linearly related to the number of cars. Industry and Freight Transport play a role: The abundance of trucks and heavy machinery dramatically increases the Leq value. Traffic alarm and traffic lights Range Less, which creates a more stable movement with a stable noise profile.

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Figure 4. A comparative analysis of the study was carried out measuring noise on the roadways of the city of Tashkent, comparing its levels

In conclusion, the 0.635 correlation confirms that the number of cars is a significant factor influencing the noise level in Samarkand. However, when developing measures to reduce noise pollution, it is necessary to take into account other factors such as the type of car, road condition, driving style and other noise sources. A more comprehensive analysis, taking into account all these factors, will make it possible to develop more effective strategies to improve the acoustic environment in the city. Roads are narrow, there are a lot of pedestrians, markets are close-traffic flow is more stop-return noise level changing. Historical constructions reinforce the sound reflection, but it is not permanent (e.g., around Registan). Other factors also affect traffic: activities on the street, standing cars, called services. High noise does not always depend only on the number of cars, that is, there are other sources of noise.

The 0.97 correlation is a very strong argument in favor of the fact that the number of cars is a critical determinant of noise levels in Tashkent and requires priority attention when developing strategies to reduce noise pollution. Anomaly analysis based on examples: 252 cars at Beruniy Street (Tashkent) 99 dB Leq. This is higher than in other places. Reason: a large number of buses and trucks move here, standing cars play a signal, near the road there is an enterprise for the production of betonautomat. 248 cars on Mirzo Ulugbek Street (Samarkand) Leq 71 dB - less noise. Reason: here the road is wide, cars walk slowly, there is a green area nearby. The exceptionally high correlation in Tashkent (r = 0.97) can be attributed to the stable and high-volume vehicular traffic patterns typical of dense urban areas with less interruption and more homogeneous flow. In contrast, the moderate correlation in Samarkand (r = 0.635) reflects more variable traffic dynamics influenced by narrower streets, irregular movement, historical architecture, and mixed noise sources. These findings demonstrate that noise levels in urban settings are not solely dependent on traffic volume but are significantly shaped by the physical and functional characteristics of the urban environment.

The differences observed between Samarkand and Tashkent in noise levels and their correlation with traffic volume can be attributed to a complex interplay of urban design, infrastructure, and vehicle fleet characteristics. Tashkent’s wide arterial roads, high proportion of heavy vehicles, and modern traffic flow infrastructure result in more stable and continuous noise profiles, hence a stronger linear correlation. In contrast, Samarkand’s older, narrower streets, mixed land-use patterns, and pedestrian density introduce variability and discontinuity into the noise landscape, weakening the correlation with vehicular counts. These findings underscore the importance of tailoring noise mitigation strategies to the unique structural and functional features of each urban environment.

The findings from Tashkent, where Leq values showed a near-perfect linear relationship with traffic volume (r = 0.97), are consistent with previous studies such as Bazaras et al. [18] in Lithuania and Danciulescu et al. [15] in Romania [19], which reported similarly high correlations in dense urban environments. Conversely, the lower correlation in Samarkand mirrors findings from Tehran, where historical infrastructure and irregular traffic patterns reduced statistical coherence. This comparative approach adds a new regional perspective from Central Asia to the global discourse on urban acoustic ecology.

Currently, the intensity of global environmental problems is increasing by the time. We have compared the main streets of Samarkand and Tashkent alone, the impact of noise on the human organism and the environmental environment is increasing significantly, and the optimization of this issue is relevant.

In this study, the results of a comparative analysis of the environmental impact of road traffic noise sources in Samarkand and Tashkent City show that the traffic flow density in Tashkent is higher, as a result of which the noise level is significantly higher than in Samarkand. In Tashkent, industrial areas, highways and traffic jams are the main factors of noise pollution. The city of Samarkand, however, has fewer vehicles and relatively lower noise levels.

Of the selected streets in Samarkand for the study, the number of vehicles in Rudakiy Street (South Market) was 308, the noise indicator was max 84 dB, the average (Leq) was 73 dB, and for a comparative comparison of the study, the number of vehicles in Beruniy Street (Chorsu hotel) in Tashkent was 252, and the noise indicator was max 99 dB (traffic cause), and the average (Leq) was 85 dB.

Therefore, it is important to expand the green areas and regulate the flow of traffic by taking sound insulation measures in both cities. To reduce the noise in the cities of Tashkent and Samarkand, it is necessary to use more public transport and optimize car traffic.

Noise pollution is one of the most serious environmental problems of modern cities. This study is considered an important scientific work for in-depth study of the problems of acoustic ecology in urbanized areas and scientific-based planning of urban infrastructure. In order to reduce their negative consequences, it is important to take complex environmental and urbanistic measures.

Active practical recommendations-in the cross section of cities:

For Tashkent:

It is necessary to limit the movement of trucks in the central regions and transfer the route to peripheral bypass roads (through transport policy). Sound-absorbing road covers (porous asphalt) and anti-noise screens must be installed (in particular, on the streets of Beruniy and Farobiy). It is recommended to introduce lower noise public transport types (electric bus, trolleybus) in stages.

For Samarkand:

On the streets near the Historical Center, car traffic should be limited, and the pedestrian zone should be expanded.

To reduce urban noise pollution in Uzbekistan’s major cities, this study suggests targeted, city-specific strategies. For Tashkent, urban planning should focus on restricting heavy vehicle movement in residential zones, expanding the use of low-noise road materials, and promoting electric public transportation. In contrast, Samarkand would benefit from traffic calming measures in historical districts, pedestrianizing core areas, and expanding green infrastructure. These recommendations are grounded in empirical noise and traffic correlation data and can inform municipal environmental and transport policies moving forward.

To be effective, noise mitigation in Uzbekistan’s cities must be context-sensitive. In Tashkent, strategies such as heavy vehicle re-routing, mandatory soundproofing for new developments, and acoustic zoning near major arteries are critical. In contrast, Samarkand requires protection of its historic core through quiet zones, expansion of pedestrian areas, and surface smoothing projects. These targeted policy recommendations are designed to align with the specific urban and acoustic profiles of each city.

This study provides empirical evidence of traffic-related noise pollution in Uzbekistan’s two major cities, revealing a significant correlation between vehicle volume and noise intensity in Tashkent and a moderate one in Samarkand. These findings highlight the urgent need for tailored mitigation strategies, such as acoustic zoning, vehicle flow regulation, and pedestrian-friendly planning. Urban noise pollution must be recognized as a critical public health and environmental issue, especially in rapidly growing cities. Future research should incorporate seasonal and temporal variations, vehicle types, and GIS-based mapping to support integrated noise management policies. Limitations include the short measurement duration and absence of vehicle-type analysis, which should be addressed in future studies.

Further research should address seasonal and daily variations in noise levels, particularly across different climate periods in Uzbekistan. In addition, studying the acoustic impact of ongoing public transportation reforms-such as the introduction of electric buses and tramway expansions-may provide evidence-based guidance for urban transport planning. Long-term monitoring and noise mapping are also essential to develop a comprehensive, real-time understanding of noise pollution across diverse urban settings.