فصلنامه جاده
سال بیست و هشتم شماره 2 (پیاپی 103، تابستان 1399)

In this study, the effect of polyethylene wax on improving the performance of asphaltic mixtures was investigated through laboratory testing. Experimental samples were taken from asphalt compacting in place containing polymer additives, especially polyethylene waxes. To investigate the role of polyethylene wax in reducing pavement fatigue cracks, samples with dimensions of 20 cm* 5 cm * 5 cm in two conditions without and with the amount of polyethylene wax and constant amount Asphalt ratio of 4.5 in all samples at different temperatures and load frequencies for fatigue were tested. Fatigue test results showed that for all three mixtures arranged with polyethylene wax in all samples, the pavement thickness after the test, for 0.09% wax, it was higher than that of the other asphalt mixtures. That is, the drop in the thickness of the pavement under the fatigue test is minimal, indicating an optimal weight percentage of the polyethylene wax executed in the pavement layer. So that the increase in the percentage of asphalt mixing with polyethylene wax from 0.05 to 0.09 percent, the decrease in the thickness of the pavement under the fatigue test decreases, but from 0.09 to 0.15 percent, the thickness drop increases. Thus, for artillery mixes with 0.09% polyethylene wax, the drop in the thickness of the asphalt pavement layer is less under fatigue testing, that is, the rate of cracking of asphalt armed with 0.09% of the polyethylene wax is minimal.

One of the major concerns of big cities is the high volume of traffic, the use of public transport, more safety and a proven solution to this problem. For reasons that are addressed in this research, many people are interested in using motorcycles at city level. The purpose of this research is to investigate the causes of citizens' tendency to use motorcycles instead of using public transportation in Qom. By interviewing the experts, the variables that influenced the use of motorcycles were determined; variables include: economic factors, factors related to the quality of infrastructure, factors related to urban traffic, and the lack of culture for the use of public transport. In this research, a descriptive-survey method was used to investigate the hypotheses and answer the research questions. The statistical population of this study includes off-road motorcyclists whose motorcycles were seized in the past month; a sample size of 341 people was determined using Morgan's table. A researcher-made questionnaire was used to collect required data in this research. A confirmatory factor analysis test and then structural equation model were used for validity of the questionnaire. SPSS software was used to analyze the collected data and to investigate the hypotheses of the research. After analyzing the data, all four hypotheses were confirmed with 95% confidence. That is, variables of economic factors, factors related to the quality of infrastructure, factors related to urban traffic and the lack of culture of using public transportation affect the tendency of citizens to use motorcycles in Qom.

Growth of population and urbanization, transport expansion as well as demand of road trips in developing countries such as Iran, cause to the increase of the number of vehicles day by day, which this matter leads to the enhancement of the unreasonable of travel time and high rate of accidents. The data of accidents show that in whole of the world around 13 million people die every year from accidents and more than 50 million people are injured or physically handicapped due to this matter. Therefore, in order to achieving the proper traffic planning to reduce of accidents number and casualties, assessing the road safety with considering effective factors is very important. In general, different methods are used to evaluation of the safety of transportation facilities, which most commonly methods of them are statistical models. The main purpose of this paper is to present an improved method, to evaluate the safety of different urban intersections by using a statistical model of urban accidents. This study was conducted on 140 three-way and four-way intersections which included lights and no lights cross. In these cases data of accidents on three years period, from 1387 to 1390, have been collected from the 113 police reports and other required data have been gathered by field investigation (research). A multiplicative form based on Haier equation has been used to build the considered model, where descriptive variables choose in continuous and binary forms and with a predetermined function are introduced to the equation. The results showed that in the urban intersections, incoming traffic has the greatest impact on accident rates, and for a certain traffic volume, effects of intersection geometry (3-way and 4-way) and also type of traffic control (signalized and no lights) on the rate of accident are negligible.

One of the intersection safety analysis methods is creating crash prediction models using the negative binomial and Poisson regression models. However, the use of negative binomial regression is preferable due to its more data dispersion. But, the research evaluates both models at first for modeling urban intersections crashes. After testing the models by criteria of Akaike information, deviation and log-likelihood, the negative binomial regression model showed a better fit and was chosen as the better model. For modeling, the data of a 5-year period of crashes occurred at the three leg intersections of Boroujerd city has been used. The input variables of the model were selected after a significance evaluation test. These variables included the number of passing lanes, the number of right turn with traffic island lanes and the skew angle. After selecting the variables, the accuracy of the model was also studied. To validate the model, the criteria of R2, root mean square error, mean absolute error, and mean absolute percentage error were used. After evaluating the model accuracy in the prediction of accidents, it was found that the model provides acceptable results for evaluating crashes, but the results are not very accurate for predicting them (R2 = 0.52). The R2 value for the model shows that the predictions will not be precise enough, but reasonable predictions can still be provided.

Various standards and criteria are existed regarding rubble mound breakwaters. Based on engineering material properties used each of them have own classification . Where as  these types of breakwaters are mainly made by rock material, knowing their  engineering properties such as durability and deterioration and destruction against predominant condition in marine environments is vital in order to preparation of proper classification system. Iranian rubble mound breakwaters in Persian Gulf, Oman Sea and Caspian Sea are mainly designed and made based on regulations, standards and criteria of other countries such as, America, Britain, Japan and Netherland. Using of these standards caused limitations such as the mismatch of the selected stone with the given standards and operating costs are increased. This paper introduces national and international criteria in order to select rock used in break waters. In the following with Concentration, on national criteria, most important indexes of these criteria presented for each type of stone.

One of road transportation issue, which has a major share of movement, is risks management to meet demand. This causes the rate of depreciation of physical assets and risk control service, safe, inexpensive, environmentally friendly and reliability. There are two views in this regard: A traditional one which manages all phases of the physical road (creation, exploitation, and disposal) separately. The second perspective is the integrated viewpoint at risk management throughout whole life of physical assets. The results of the survey show that so far 55 risks have been identified in 6 groups for road physical asset. In risk assessment, the most risk associated with contribution of the stakeholders group and the least, is related to an out-of-area event group. In addition, the lowest level of risk associated with the risk of robbery and insufficient attention to maintenance is the highest among all the risks. Some proposal for managing risks is integrated development and operation system, a sustainable financial program; determine level of service and training of human resources.

Traffic accidents are considered as the main cause of death among young people in the world and the biggest problem in developing countries such as Iran.  Planning to reduce pedestrian accidents requires proper information. Therefore, the purpose of this study was to determine the accident points in terms of pedestrian accidents in the second trimester of summer 2017 in Shiraz. This is a cross-sectional study. Data from pedestrian crash statistics were extracted from the pre-hospital emergency database. Valid items with interstitial address in Shiraz. The map of the roads of Shiraz was designed according to the scale and coordinates. The latitude and longitude of each address was calculated and implemented on the map. After recording the points where pedestrian accidents occurred, the operation optimization method and the density analysis of points were applied. Such a map of the frequency of pedestrian accidents and the density of incident points were made at the city of Shiraz. After analyzing the map and examining the distribution of the age and sex of the injured, the frequency of pedestrian accidents was obtained in different months. A map of pedestrian accidents occurred in summer 2012 in Shiraz. The main accident occurred at the Shiraz level in the city center and the lowest density in the south and southwest region. Considering the significant level of 0.1, the highest accident density was in areas 1, 3, 4, 7 and 8 of Shiraz municipality. 74.4% were injured and the rest were women. The most pedestrian accident occurred in July and the lowest frequency was in August. The age group was 16-44 years and over 65 years old and the average age of pedestrians was 35.6 years.The density of pedestrian accidents in the city center was significantly higher than in the south and southwest of Shiraz. The need to investigate the causes of an accident, including human error, vehicle defects, and road problems, such as lack of lighting, are felt in accidental areas. With the presence of police special forces at incident and measures such as the construction of pedestrian bridges, the pedestrian accidents can be greatly reduced.

Although structural health monitoring systems have considerably advanced during the last decades, they are still expensive. Moreover, the existing low-cost systems use numerous sensors. Therefore, due high price of sensor hardware they are uncommon in our country. Owing to this, reduction of sensor numbers can be a step forward toward naturalization of such systems. In this paper, a health monitoring algorithm is proposed base on signal processing. Only one sensor is employed to detect damage. Since reduction of sensor numbers can affect the accuracy of damage detection, in the first step of the paper, several signal processing techniques are compared and the best one for this case is selected. Next, two damage indices are introduced based on frequency dispersions. Time-series analysis is utilized to tackle fluctuation of damage indices. Finally, a damage threshold is defined to distinguish damaged and healthy states. Results show that frequency itself is not an appropriate damage measure. Instead, frequency dispersion can be used as alternative damage criteria.

Assessment of pavement distresses plays a pivotal role in pavement management systems in determination of the most efficient option for repair and maintenance of the road. In the past decade, extensive researches have been made in order to develop automatic methods for pavement distresses processing based on computer vision techniques. Of the most important components comprising machine vision systems is the feature extraction procedure. In many image processing applications, textural features provide more effective information about the properties of the image regions in comparison with other features.  In the present study, three different algorithms were utilized with the purpose of statistically analyzing the textures of six different groups of asphalt pavement distress images. The first feature extraction algorithm is based on gray level co-occurrence matrix (GLCM) textural statistics. In second and third algorithms, the second-order textural descriptors of the images local patterns were extracted in spatial and wavelet domain, respectively. The distress categorization results based on a fusion of K-nearest neighbor (KNN) classifier and Mahalanobis distance, indicate that two level (double) regularizing the distress edges gray levels via employing wavelet transform and local binary pattern (third algorithm) outperforms other textural feature extraction algorithms in pavement distresses recognition and discrimination. The distress classification accuracy rate based on first, second and third algorithms were 61%, 75% and 97%, respectively.

Nowadays strategies as futuristic thinking, role essential in coordination strengths, and opportunities in resolving weaknesses and encounter with a threat. But strategies in the implementation stage are always surround by factors that challenge or reinforce them in the path to success. This study aims to focus on the barriers to the implementation of urban sustainable transport strategies, and how these barriers will be affected. The statistical population of the study included 72 urban planning and urban planning experts who had good information about urban transportation systems. The framework for selecting individuals provided that they have at least ten years of experience in the areas mentioned and informed about Hamadan's urban status. The purpose of the study is applied and based on a descriptive and survey research strategy and a questionnaire was used for data collection. Its reliability was obtained by calculating Cronbach's alpha coefficient of 0.82. The Kolmogorov-Smirnov test for how the data are distributed in terms of normal or abnormal components to determine the relationship between the identified nine fold barriers and the implementation of the Spearman test as well as the Friedman nonparametric test for ranking the nine fold barriers. The highest average rating of 4.73 is assigned to social security, which means that the most important obstacle for experts to implement sustainable urban transport development strategies is social security. After this factor, the managerial and physical barriers have been most influential in this regard. The results of the statistical analysis confirm the existence of nine obstacles in the implementation of strategies in this area. In order to reduce the uncertainties of social deterrence, it is recommended to develop appropriate mechanisms for the development of social and institutional stakeholder participation, along with the process of designing transport strategies and urban transport strategies.

Seasonal variations in skid resistance have been a recurring phenomenon that has been studied by many researchers. The impact of seasonal variations will vary across geographic regions, due to different amounts of rainfall. During the summer months, especially during prolonged dry periods, small rock chips on the surface continuously become fine-grained particles as vehicles move and act as a polishing agent. During long rains (winter months), fine matter disappears and the heavier and more coarse sand acts as a polishing agent, resulting in slippery resistance to surface texture. Increase the coarseness. Many variables affect the measurement of skid resistance. It is not yet possible to fully investigate the possible influence of various factors affecting the seasonal variations in skid resistance. Precise measurement of seasonal variation in skid resistance is a relatively complex task. This paper introduces and investigates various methods of seasonal slip resistance correction available in the world and evaluates their feasibility of usage in Iran.

There have been many studies on how to model problem types, develop problem assumptions to adapt to real-world application conditions, and develop or develop problem-solving methods to obtain better results. In this paper, we aim to use single-target bat algorithm for drug distribution process in Tabriz metropolitan area in order to solve the problem of vehicle routing with time window. Due to the continuous nature of the metadata algorithm, how it is generated and decoded, a new routing solution is designed that gives the shortest transport path in the shortest possible time. In this regard, the distribution of the drug has been considered by Mohyadaru Distribution Company, a non-technical business-service company. In order to evaluate the performance of the proposed method, issues of different dimensions have been applied based on the actual issues related to drug delivery to existing pharmacies in the city of Tabriz by Mohyadaroo Company. The results show that the optimal routing is done due to the nature of the meta-algorithm optimization and the costs spent for this task are significantly reduced compared to the previous work.