ABSTRACT This research models the relationship between traffic characteristics and lane position on a six-lane divided highway. Both macroscopic and microscopic models were developed to analyze speed-density, speed-flow, and flow-density relationships for each lane, using linear and nonlinear approaches. Additionally, microscopic models were created to investigate speed-spacing, speed-headway, and headway-spacing relationships. Data was gathered using video recordings and radar speed guns, and traditional methods were applied to calculate density and spacing distance, which are typically challenging to measure in the field. Microsoft Excel and SPSS ver.26 software were utilized for analysis. The coefficient of determination (R-square) and the chi-square test were employed to assess the goodness of fit for the models. The results indicated no significant differences between the predicted and observed data, demonstrating critical traffic characteristics and providing insights into vehicular and driver behavior. These models can be utilized to identify various parameters of traffic characteristics in future studies on the examined highway.
The reduction of gases emissions as one of its most significant long-term strategies in any country in the world. Many Iraqi cities suffered from the uncontrolled increasing in the number of vehicles which has a positive relationship with the emission of gases especially the carbon monoxide. This study aims to evaluate the effect of traffic characteristics such as logarithm of average flow, the percentage of heavy vehicles, and free flow speed on the emission of carbon monoxide. The study selected the main roads in Al- Ramadi network, the data was collected for traffic characteristics and carbon monoxide between 2018 to 2020. A random parameters approach was used to develop a model to estimate the carbon monoxide emission for 345 roadway segments, this approach was used due to the ability of this method to account the heterogeneity that raised from the traffic characteristics which led to predict more accurate results than other approaches. The results of the random parameters model show that the carbon monoxide emission increased due to increase of logarithm of average flow, the percentage of heavy vehicles, and free flow speed. The model results show that the parameters of logarithm of average flow, the percentage of heavy vehicles, and free flow speed was varied a cross the roadway segments.
The geometric design of highway alignment consists mainly of the design of horizontal alignment and Vertical alignment. The more important step in horizontal alignment design is the curve radius determination. The equation used for horizontal curve radius determination is developed with assumption that when vehicle run on curved section, there are an acting force on it. This force include the centrifugal force that try to push vehicle out off its path , on the other hand there are resisting forces try to keep the vehicle on its path. Those include the friction between road surface and tires and forces resulting from sloping the highway cross section. When a vehicle on rural highway with high embankment the wind Pressure will play an important role in force system acting on vehicle because of increasing in wind pressure intensity at these conditions (rural highway, i.e open areas, high embankment). The purpose of this paper is to present a new equation for horizontal curve radius determination taking in to account the wind force effect in addition to other forces acting on vehicle The resulting equation relates vehicle length, height and weight and the wind pressure as well as the other factors in traditional equation. Effect of each parameter on design radius was investigated for the case where the wind direction is acted with the same centrifugal force direction. It has been found that the required minimum radius increase with the decreasing of vehicle weight or in the other words the vehicle permitted speed decrease with the decreasing of vehicle weight. On the other hand, the required curve radius increases with vehicle height increasing. Consequently, permitted height of bags loaded on a truck is related to the type of loads. Derived equation can also be used for estimation of the permitted truck speed on existing roads especially in case of bad weathers The comparison between the traditional and suggested equation showed that maximum difference is about 160 % which results at high wind pressure while the difference is up to 20 % for low wind pressure
The frequency of accidents, as well as statistical models of accident frequency, are often used as a foundation for prioritizing improvements to roadway safety by several transportation organizations. However, the use of accident severities in safety programming has frequently been restricted to the locational assessment of accident fatalities, with little or no emphasis being placed on the full severity distribution of accidents (slight damage, serious damage) which is required in order to properly evaluate the advantages of several competing efforts aimed at improving safety. Within the scope of this research, we provide a sufficient modeling technique that may be used to get a better understanding of the accident severity level that occur on highway segments, as well as the influence of traffic characteristics such as annual daily flow, percentage of heavy vehicle and free flow speed. The modeling approach that used in this research (random parameters model) provides the possibility that the estimated values of the model parameters might differ from one road segment to another to account the heterogeneity of the independent variables. The estimated random parameters models are developed using accident severity data and traffic characteristics data that obtained from Fallujha – Al-Qaeam rural multilane road in Al-Anbar province, Iraq. The results of the estimated results suggest annual daily flow, percentage of heavy vehicle and free flow speed all have significant effect on the accident severity level. For the purpose of prioritizing highway safety improvements, a number of government transportation authority’s base their decisions on accident rates and statistical models of accident rates. The random parameters models have been shown to have significant potential for use as a sufficient method in the programming of highway safety.
ABSTRACTAn operational analysis is an analytic evaluation of operation on an existing freeway ramps. In this case, all traffic and roadway conditions must be specified. The output of operational analysis is an estimate of the level of service for the ramp in question and of the approximate speed and density at which the traffic stream operations.A ramp is length of roadway providing an exclusive connection between two highway facilities. On freeways, all entering and exiting maneuvers take place on ramps those are designed to facilitate smooth merging of on-ramp vehicles into the freeway traffic stream and smooth diverging of off-ramp vehicles from the freeway traffic stream onto the ramp.The aim of this paper is the operational analysis of ramps on existing 6-lane freeway. This analysis involves the consideration of known freeway of Mohammed Al-Kasim freeway in Baghdad city. Given known geometric roadway conditions and projected traffic conditions, the operational analysis yields an estimate of the level of service and of the speed and density of the traffic stream. This paper has described the procedure for determining the level of service on Mohammed Al-Kasim freeway ramp sections as presented in the Highway Capacity Manual (HCM, 2000). Levels of service are determined for all ramps of the freeway using )HCS2000( software. Level of service of all ramps are similar at AM and PM peak hour periods, because the data was collected under ordinary traffic conditions.
The main objective of this study is to evaluate the comparative performance of three artificial neural network techniques (radial basis functions “RBF”, multilayer perceptron “MLP”, and group method of data handling “GMDH”) based approach with the Penman–Monteith “PM” method for determining the group reference evapotranspiration “ET0” on monthly basis in Basrah City, south of Iraq. Climate information extends over 22 years (1991- 2012), monthly records of maximum temperature (Tmax), mean temperature (Tmean), minimum temperature (Tmin), wind speed (U) and relative humidity (RH) are used in this research. The architecture of artificial neural network models is performed during the process of training. The efficiency of trained model is checked by using the testing data, which is not used in the process of training. The evaluating of the artificial neural model performance is carried out by using cross-validation, a set of rows for each validation fold is determined randomly after stratification on the target variable “ET0”. Various set of climate inputs variables are used for creating nine artificial neural network models. The efficiency of artificial neural network models with two predictor variables (Tmean & U) for simulating ET0 is highly efficient according to the evaluation criteria. There is a significant improvement in the results of all artificial neural network models when using three input combination variables (Tmean, U, & RH) compared with the models that have only two-climate variables. Artificial neural network models especially (RBF, MLP, and GMDH) are efficient and powerful techniques for simulating ET0.
Abstract The purpose of highway geometric design is to provide safe and economical highways. One of the utmost important geometric design element for safely travel that should be satisfied is visibility on designed road. This can achieved by providing adequate sight distance in both horizontal and vertical alignments. Minimum sight distance that should be provided at all points along highway is stopping sight distance SSD. In the design of vertical curves AASHTO's Geometric design Policy uses the sight distance requirement as a major criterion in curve length determination. Moreover, sight distance has great effect on highway constructional cost because more required sight distance means more vertical curve length, which in turn means more earthwork materials. Consequently, safety and economics can be considered as a major criterion in design of highways. The AASHTO's model involved design speed, perception-reaction time, and frication factor as a parameters used for SSD computations on level sections. On inclined surfaces, an additional parameter denoted by (G), which reflect grade of sloped surface on SSD. In the present paper a new approximate methodology and Equations are formulated though which a suitable design grade value can be estimated on vertical curves where the grade not constant then utilizing this value to compute SSD on these curves and hence compute vertical curve length corrected for grade effect. Generalization of present methodology is carried out by derivation a general mathematical solution. From these derivations it has been found that the suitable grade value for Type I and Type III (initial and final grade are descending and ascending) is half of the largest grade among G1 and G2. While the design grade value is the average value of G1 and G2 for Type II and Type IV (both grade are descending or ascending). Comparison with other grade estimation on vertical curves suggestions showed that the present methodology produces more reasonable and economical value because the obtained length is no longer to be uneconomical as compared with other suggestions. At the same time it provides a safe value used in all design cases those reflects the actual case as compared with other suggestions those ignored or reduced the effect of grade.
Chlorine contact tank in water and waste water treatment plant suffer from a lack of efficiency disinfected treated water, which discharge to the rivers and they need a large amount of chlorine for the purpose of disinfection as a result of the presence of dead zones in the basins of chlorine as well as the need to contact a long more than exact standard specifications for the tanks disinfection time. This study deal with optimal performance basin mixing chlorine, which is located at the beginning of Chlorine contact tank of waste water treatment plant in the city of Nasiriyah in Dhi Qar, which is located south of the province of Iraq. In this paper, the use of computational fluid dynamic model in the numerical analysis for the purpose of finding the optimum performance of the chlorine mixing tank with the help of the program FLUENT 6.3.26 and program GAMBIT 2.3.16. Also in this study was used User Defined Function for the purpose of improvements of mixing chlorine. Where the results of the study showed that the ideal rotational speed of the mixer is 140 rpm as well as the results showed Numerical Model that can reduce chlorine dose to 5 mgliter, which is the optimum concentration of chlorine to be supplied for wastewater disinfect and is identical to the Iraqi specifications water sanitation, which discharge to the Euphrates River. In this study the best contact time of chlorine which give the best performance for mixing was 20 seconds.
Concrete is by far the most widely used construction material now today. Foamed concrete is light building material with good strength as well as low thermal conductivity and easy workability; it is produced by either Mix Foam Method or Preformed Foam Method. Ultrasonic Pulse Velocity(UPV) is a non destructive technique involve measuring the speed of sound through concrete in order to predict concrete strength and to detect the presence of cracking, voids, decay and other damages. This research includes three main experimental stages:- The first stage includes the production of foamed concrete and it was divided into two parts, the first part, mixing design(determination the proportions of the raw materials) was presented in the second part, the mixing procedure has been illustrated. The second stage includes preparation of samples,(i.e. molding, finishing surface, removal from molds, and curing). The third stage includes several teste to estimate properties the final product and factors influencing them, these properties include density, compressive strength, and the ultrasonic pulse velocity. From the experimental work and at the same test's age, the compressive strength and the ultrasonic pulse velocity for foamed concrete with 800 kg/m3 density were respectively (2.38 MPa,1.56 km/s)and the compressive strength and the ultrasonic pulse velocity for foamed concrete with 1200 kg/m3 density were respectively (3.7 MPa,1.96 km/s) while it were (7.8 MPa and 2.12 km/s) for foamed concrete with 1600 kg/m3 density
Multilane highways typically are located in suburban communities, leading into central cities, or along high-volume rural corridors connecting two cities or significant activities that generate a substantial number of daily trips. The objectives of the present study include the analysis, and evaluation the level of service (LOS) on section for multilane highway in Ramadi city. The LOS multilane highway is based on density, which is calculated by dividing per lane flow by speed. The required traffic and geometrical data has been collected through field surveys on the section for multilane highway. Traffic volume data were collected manually and classified by vehicles types during each 15 minute interval. Highway Capacity Software 2000 (HCS 2000) program is used for the requirements of traffic analysis process to determine the level of service. It has concluded that the level of service on selected section for east bound is (A), and for west bound is (B).
Traffic engineers frequently are engaged in evaluating the performance of different facilities of the highway system. The facility in this project includes freeway section. In design of a freeway, a forecast demand volume is used with known design standards for geometric features and a desired level of service to compute the number of lanes required for the freeway section in question. The design application is straight forward for each usage, but trial-and- error operation analysis may be required to evaluate alternative design. Design requires a detailed traffic forecast, including volumes, peaking characteristics, traffic composition, and specifics of vertical and horizontal alignment for the section under study. The aim of this paper is the design analysis of a freeway with a heavy recreational vehicles. This analysis involves the consideration of three examples of freeways. Given known geometric roadway conditions and projected traffic conditions , the design analysis yields an estimation of the number of lanes and of the speed and density of the traffic stream. This paper has described the procedure for determining the number of lanes of freeway basic sections as presented in the Highway Capacity Manual (HCM, 2000) and HCS2000 software.
Traffic control devices notify road users of regulations and provide warning and guidance needed for safe, uniform, and efficient operation of all elements of the traffic stream. Traffic control devices have been a part of the roadway system. Researches have evaluated various aspects of the design, operation, placement, and maintenance of traffic control devices. The purpose of this research is to develop a simulation model in order to evaluate the effect of overhead sign position on the traffic performance at exit of freeway weaving area. To achieve that subroutine was developed and added to FWASIM program to compute the sign position and compare it with the driver sight distance. Following that a proposed example represents an exit weaving area was examined with different traffic flow configuration (different percentages of link flow and on-ramp flow) with respect to no sign installed and other three sign positions. Results indicate that the average traffic speed is underestimated when there is no sign installed, while no significant effect is shown when the sign position is changed within the driver sight distance. In conclusion Guide signing is a critical element in the effective, efficient and safe operation of motorways and expressways. Signing issues must, therefore, be fully considered at the feasibility stage of any project.
Surface infiltration plays an important role in watershed management and flood forecasting; Furthermore increase the efficiency of irrigation system and reduce water losses during the irrigation process. Experiments carried out on the Wadi AL-Ratga of the western desert, Iraq during 2019; which had been selected as a study area. The infiltration rate data were collected using double ring infiltrometer at selected ten points of the selected study area. The duration of double ring test ranged between 30 minutes to one hour based on the infiltration speed in the soil, about 6 to 12 readings were recorded for the infiltration rate at each points. The aim of this paper is to check the ability of the common infiltration models such as Horton’s, Kostikov’s and Philip’s to accurate estimated infiltration rate. These models were fitted to the observed infiltration data for estimation of models parameters and to find appropriate model for this region. Horton’s infiltration model’s parameters such as infiltration decay constants ’k’ And the value of infiltration capacity at onset of infiltration (fo) had been calculated in the ranges of 3.38-6.97 hr-1 and 21 to 47.8 cm.hr-1; respectively; for all the ten points. Philip’s infiltration model’s parameters such as the values of conductivity constant ‘A’ and sorptivity ’S’ were obtained in the ranges of 3.48-12.49 cm.hr-1 and 9.96 to 17.2 cm/hr0.5; respectively. Similarly; the Kostikov’s model’s parameters ‘a’ and ‘b’ were obtained in the range of 8.85-24.38 and 0.732-0.829; respectively. Based on results of infiltration models at the selected points the predicated parameters have realistic capability predication. The results showed that all models provided the acceptable values for Root Mean Square Error (RMSE) as1.45, 2.01, 1.88 cm.hr-1 for Horton’s, Kostikov’s and Philip’s model; respectively; The highest model efficiency (ME) as 99% for all models; and the maximum Relative Error (RE) values as 16% at all points except point 2 was calculated as 21%. This indicated that infiltration can be well-described by the Horton’s model little more than other models at the study area.