Selected Indicators of Al-Najaf Road Network: Public Transportation Noise and Pollution

. It is urgently necessary to improve the state of transportation and related infrastructure, especially given that the most important indicators of urban development gauge a city's progress. One of the most influential of these indicators is what is known as "smart transport," which refers to transportation that utilizes modern communication and information technology technologies to address various challenges in various transportation sectors. The holy city of Najaf smart transportation strategy seeks to reduce dangerous levels of traffic-related noise and air pollution while enhancing various aspects of mobility and traffic flow indicators. This study aims to evaluate the performance of the existing traffic network and public transport in Najaf City and its interference with noise and air pollution at selected points for data gathering by using field measurements using cameras, noise meters, and pollution measurement devices. The study states that the public transport sector in Al-Najaf city is significantly poor as private cars are dominant by about 65% of traffic mix with values of pollution and noise above the standards. One of the most effective solutions to traffic problems is the implementation of intelligent transportation systems. Part of these strategies is establishing a tram network and raising road classes’ strategies by proposing some geometric design editing, U-turns reducing, and raised ramps additions.

There are several definitions of public transportation.Walker [12] proposes one of these definitions, stating that public transportation "consists of regularly scheduled vehicle trips, open to all paying passengers, with the capacity to carry multiple passengers whose trips may have different origins, destination, and purposes".The author deconstructs this definition to explain its components.By "regularly scheduled vehicle trips", Walker [12] demonstrates that transportation is provided by a vehicle that follows a set schedule or pattern; however, routes and schedules may vary.Public transportation should be predictable so that different people can plan around it without communicating directly with each other.Walker [12] identifies this as the primary distinction between transportation and other modes of transportation.Public transportation networks are deemed crucial to the sustainability of metropolitan regions for a variety of social, environmental, and economic reasons, such as ensuring access to activities and services, reducing traffic congestion, increasing productivity, and lowering carbon emissions [13].

Noise Generated From Traffic
A vehicle's engine, exhaust, tire interaction with the road pavement, the contact of moving cars and passing air, road quality and traffic control, vehicle speed, and traffic patterns are just a few variables that lead to increased road traffic noise, particularly on highways.The noise level on the highway grows as the road's width narrows and the buildings' height rises [14].Using typical outdoor noise exposure indicators, the impact of road traffic noise is determined [15].The weighted equivalent continuous sound pressure level in the specific daytime or over 24 hours is one of the most used noise indicators.The regulatory agencies use this indication in evaluation guidelines and regulations [16].On the other hand, standard indicators of traffic noise are insensitive to identifiable traffic noise occurrences.And temporal noise profile variation [17].International noise limits (Central Pollution Control Board (CPCB)) and World Health Organization (WHO) is 65 dBA and 70 dBA, respectively [18].

Traffic Flow Pollution
The transportation sector is the reason for around a third of the atmosphere's chlorofluorocarbons (CFCs), 20% of its carbon dioxide (CO2), and 50% of its nitrogen oxides (NOx) are released by fossil fuel combustion [19].Air pollution caused by traffic is a significant problem for the general public.Automobile emissions of nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOC), and particle matter (PM) are significant causes of air pollution in Hong Kong and other metropolitan cities.Air pollutants generated by traffic, such as NO2 and PM, pose a health risk, while greenhouse gases generated by transportation, such as carbon dioxide (CO2), may contribute to global warming.As motor vehicles are the primary source of urban air pollution, it is necessary to create management measures that reduce environmental impacts while maximizing the efficiency of motorized transport [20].The air quality index (AQI) is the function to indicate emissions as stated by Environmental Protection Agency (EPA).See Table 1.The US EPA bases its definition of AQI on the five leading pollutants: sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and particulate matter (PM10 and PM2.5) (SO2).The index of each pollutant individually , as specified in the equation below, is first calculated using concentration data from the linear interpolation formula and reference concentration data [21]: Where: IP=Index for any pollutant (P) CP= Concentration of pollutant P BPHI= A breaking point that is equal to or greater than CP BPLO= A breaking point that is equal to or less than CP IHI= AQI value correlates with BPHI ILO=AQI value correlates with BPLO Table 1: EPA standards of AQI and traffic flow emissions [16].

Travel Time
The time necessary to travel between two points of interest is known as travel time.By following the route(s) that connects any two or more points of interest, it is possible to reach them.It is possible to calculate travel time precisely.Running time, or the amount of time the mode of transportation is in motion, and paused delay time, or the amount of time it is halted (or traveling at a speed slow enough to be stopped, typically less than 8 mph or 5 mph), comprise travel time [22].When traffic control is present on a section of roadway, vehicle velocities decrease below the average running speed.The average travel speed is the speed factor that best represents the impact of traffic management.The segment length divided by the average journey time is used to calculate this speed.The whole time required to cross a street segment, including any stop-time delays, is the travel time [23].

Previous Studies
Al-Jameel and Abdabbas [24] studied the existing public transport in Al-Najaf City, and the study came up with conclusions that the current public transportation system has many deficiencies in terms of researched public transportation infrastructure, including individual buses, trams, schedules, and even routes.Their study made suggested plans for BRTs and trams as effective and sustainable means of transit.A study conducted by Mansour [25] on the effect of noise and pollution in a selected urban road network stated that Al-Matar Street had the highest average noise level across all areas, which was 87 dBA, exceeding both WHO and CPCB guidelines.Moreover, Al-Najaf-Kufa Street has the highest CO content at around 8 ppm, below EPA and WHO guidelines.However, CO2 levels are all within the permitted outdoor limits everywhere.At Al-Hizam Street, SO2 levels were high (0.9 ppm), exceeding WHO and EPA guidelines.Moreover, Al-Hizam Street's NO2 content was exceedingly high (1.05),above the restrictions.All sites' Air Quality Index (AQI) revealed a highly hazardous pollution situation.
Abdulkareem [26] studied the evaluation of noise pollution indicators in Najaf City.Their study stated that industrial areas had the most significant value of (Leq), 108.44 dB, followed by commercial areas at 89.55 dB, educational places at 87.1 dB, quiet regions at 80.4 dB, and residential areas at 69.05 dB.The noise assessment for their study highlighted the unsettling situation of noise pollution in the city of Najaf, where the highest values of Leq in all locations were higher than the allowable level in the Iraqi guidelines.

STUDY AREA AND METHODOLOGY
Al-Najaf governorate's capital is Al-Najaf City.It is situated in the country's central region, some 160 kilometers south of Baghdad.The city is located at 32°01'33.4°Nand 44°20'46.5°Elatitude and longitude, respectively.The selected data points in Al-Najaf City have been surveyed, as clarified in Figure 1 and Table 2. Urban structure refers to the city's physical layout or structure, particularly regarding economic and transportation activity [27].Another definition could be the spatial style or configuration of discrete components, such as structures and land use, as well as economic and social activities, public institutions, the population's distribution, and networks connecting them; conversely, spatial structure is the spatial distribution for the inhabitants and land use in the urban area, or the appearance of the daily trip within urban areas [28].The transportation network is integrated with the urban structure.Al-Najaf has experienced significant urban development because of the city's religion, position, and connections to neighboring areas.This development is mainly dependent on the possibilities for acceleration that occur in population growth which is either normal growth or growth brought on by immigration from various locations for various causes over time [29].The following table states the selected streets and their descriptions.Ring road (Elevators street) 3 10 Najaf Technical Institute street 3 The study focused on gathering information about traffic performance for the existing network and its environmental effect at specified locations based on high activities and types of roads.It used the camera to record videos to extract traffic volumes from 6:00 A.M to 9:00 A.M trying to cover peak hours.

Video camera
Bushnell radar device Noise level meter HUMA-I (HI-150) Advanced Sense Environmental Test AQDPI The speed gun (Bushnell radar) measures the free flow speed and spot speed data over time.Trafficgenerated noise is also measured using a noise level meter at the shoulders, and pollution emissions have been monitored and recorded using Advanced Sense Environmental Test Meter, Air Quality Detector Precision Instrument (AQDPI), and HUMA-I (HI-150).Traffic mix has been computed and listed for each type (Private cars, taxis, minibusses, buses, trucks, MTRs, and Motors) and their percentage to clarify public transport assessment.The existing public transport in the city of Najaf is represented generally by several routes starting from Al-Najaf internal garage (Origin A to Destination B) runs by minibusses; these routes don't cover the entire city, and the actual need for people transit as shown in Figure 3 and Table 3.

Origin
Route Destination

RESULTS AND DISCUSSION 4.1 Travel Time
Travel time in the study area has been measured to state the network performance and travel delay due to congestion; for the test, the travel time at Najaf-Karbala Road on 3 runs for each direction with a length of 18 km, as shown in Figure 4 and Table 4.

Traffic Volumes and Flow Rates
Traffic volumes and flow rates have been calculated for every 5 minutes at the study points using video cameras in the morning (6:00-9:00) A.M trying to cover peak hours on different days.Here are some examples.See Table 5.After data analysis, it's obvious that flow rates experience high values starting from 7:15 A.M to 8:45 A.M with an influence reduction in speed as demonstrated in Figure 5 below:

Traffic Mix
Traffic mix means the variety of vehicles on roads, such as private cars, taxis, minibusses, trucks, motors, and MTRs.The following table represents the noticeable dominant percentage of private cars all over the main roads in Al-Najaf city, see Table 6.

CONCLUSIONS
The main points resulting from this study can be concluded as follows: • Road users in Al-Najaf city depend mainly on private cars, within a percent of nearly 65% of the traffic mix.• The public transport sector is represented by about 10% of minibusses with no schedule and without fixed routes, except the Najaf internal garage.• Bus transit in the city is less than 1% all over the selected streets; most of it belongs to travel companies.
• Taxi services in the city miss regulations and management as it runs by individual drivers.
• Noise levels due to traffic are very high, reaching 94 dBA at some locations considered above the standards.• Traffic pollution led to an unhealthy environment and an air quality index above the global limits.
• The study recommends using smart transport with no fuel consumption, almost zero emissions, and a lower effect of noise.One of the modern unique solutions is implementing a tram network in the city.

Figure 1 :
Figure 1: Location of the selected data point.

Figure 2 :
Figure 2: Tools used in the study.

Figure 3 :
Figure 3: Public transport routes in Al-Najaf City.

Table 2 :
The selected roads in the study area.

Table 3 :
Existing public transport routes in Al-Najaf City.

Table 6 :
Traffic composition percentage for each street.

.4 Noise Generated from Traffic Flow Noise
values in the study area were measured at daylight in midblock sections by noise level meter and compared within international limits Central Pollution Control Board (CPCB) and World Health Organization (WHO), see Table7.

Table 7 :
Noise generated in the study area.

Table 8 :
Example for traffic pollutants at Kufa-Najaf Street in PPM.

Table 9 :
AQI values in the study area.