نشریه مهندسی ترافیک
پیاپی 91 (زمستان 1401)

The delay in the implementation of urban train projects causes significant costs such as "opportunity cost", "depreciation of the construction period" and "end of contract guarantee period and equipment warranty before the start of operation". The main goal of this research is to investigate the factors affecting the increase in the cost and time of construction of an urban train line in Tabriz. For this purpose, a non-random statistical sample of 24 experts was selected. Data collection was done through conducting interviews and distributing questionnaires among them. After checking the validity and reliability of the research, Shannon's entropy method was used to analyze the research findings. The results of the research show that the costs of implementing the project of one urban train line in Tabriz have increased by 435% (in constant price) compared to the initial estimate, and the duration of the project has reached more than 21 years instead of 7 years. In other words, the real cost of each kilometer of a Tabriz city train line was 14270 billion Rials at the price of 1400. Also, the results of the research indicate that the most important factors affecting the increase in the time and cost of the implementation of the Tabriz urban train line project are: the lack of realistic forecasting of costs at the beginning of the project, the failure to pay credits on time, the delay in providing land from the municipality, problems caused by the performance of the employer and consultants and contractors and equipment suppliers, differences in the urban management complex and problems caused by sanctions.

The transportation of cash, banknotes, and other valuable items is known as one of the new branches in the field of Cash-In-Transit (CIT). Due to the high-value density of these products, incorporating security strategies in carrier operations is crucial. In this regard, this paper provides a two-stage stochastic transportation model with traffic uncertainties at different times of the day in an inner-city multigraph network. The presented model not only yields to provide a new approach for calculating the travel risk but also helps to increase the quality of the obtained solution by considering multicharacteristic arcs (including time and travel risk). Taking into account various constraints such as maximum travel time, travel risk, and the presence of multi-characteristic arcs with stochastic traffic conditions brings high computational challenges.To this end, a multi-stage hybrid optimization algorithm is proposed to solve the problem. Finally, the proposed model has been implemented on the Isfahan city network and the results have been reported.

Transit Routes Design (TRD), in this paper, deals with finding the configuration of public transportation routes so as to achieve the maximum demand coverage over the network while holding the budget constraint. To tackle the TRD problem, many heuristic methods have been presented which are capable of finding solutions close to the global optimum in a reasonable amount of run-time. Though, little has been done to deal with specific network topologies. This paper aims at introducing and evaluating the performance of a local search “hill-climbing” algorithm to deal with the TRD problem in urban “grid” networks. In each run, the algorithm performs 20 replications each with a random initial solution, and improves the available solutions through slight changes in the routes configuration and moving to neighbor solutions. The comparison of the coverage obtained by the presented algorithm against the global optimal solutions in a 6×10 grid network with 30 random demand matrices, indicates that the presented algorithm is capable to find solutions with an average of 4% coverage less than the optimum in less than 20 minutes run-time.

Roundabouts usually have higher traffic safety compared to other types of intersections. Despite the transformation of intersections into roundabouts, high-severity accidents still occur in them. Improving accident prediction models and their parameters can help prioritize action and reduce the cost of geometric modification. This research aims to investigate the geometric factors of severity and the number of accidents in the weaving section at these roundabouts. In this research, by using the accident statistics of six roundabouts located in Qom city, the influencing factors on the severity and number of accidents were investigated using the logit model and gene expression algorithm. The results showed that the width of the weaving section had the greatest impact on the occurrence of accidents compared to other geometrical variables of the roundabout. Also, the type of accidents in which there was a vulnerable user such as a bicycle and motorcycle greatly increased the probability of being injured in the accidents, on the other hand, the presence of unauthorized access to the circular carriageway of the roundabout increased the severity of accidents from damage to injuries.

Traffic lights are important means of establishing order, safety and traffic flow control. The purpose of this research is to investigate the effect of intelligentization of intersection traffic lights on traffic flow indicators. For this purpose, the calibration of the Synchro intersection simulator software was done and then the conditions of the intersection before and after the intelligentization were simulated in it and the results were compared. No significant relationship was found between the improvement of delay time due to intelligentization of lights with cycle length, traffic volume and delay time (intelligent and nonintelligent lights). The lack of coordination and matching of the traffic light cycle with the volume of traffic was the main cause of the delay in the unintelligent mode. The maximum points of delay time improvement were in the places of cycle change in the non-smart light. The time improvement values were also proportional to the change value of the smart light cycle changes. The process of cycle changes in the smart light was proportional to the changes in delay time improvement. Latency improvement did not follow a normal distribution and tended towards lower numbers.

Today, the metropolis of Tehran, like many metropolises in developing countries, is facing serious problems due to the ever-increasing demand for transportation and the problems of the public transportation system. One of these problems is the widespread use of motorcycles in these cities, which has caused an increase in air pollution, noise pollution and accidents. Today in our country, due to the high number of traffic accidents, the issue of safety, especially the safety of motorcycle riders, is of great importance. Therefore, this study has been conducted with the aim of identifying the factors affecting the damage or injury of motorcycle accidents in Tehran city with the help of information from accident forms filled by traffic police officers at the accident scene in May and November 2013. The double logit model was used to build models of motorcycle accidents in May and November 2013 in Tehran. The results show that factors such as the type of land use where the motorcycle accident occurred, the direction the motorcycle collided with another vehicle, the type of road and the lighting of the air have an effect on the severity of the motorcycle accident and, as a result, whether it is injured or damaged.

Gasoline engine passenger cars are one of the most significant sources for emissions of local pollutants, namely, Carbon Monoxide (CO), Nitrogen Oxides (NOX), Sulfur Oxides (SOX), and Particulate Matters (PM), as well as emissions of greenhouse gases including Carbon Dioxide (CO2), Nitrous Oxide (N2O), and Methane (CH4), which has resulted in Tehran ambient air being noncompliant with legal air quality standards. This article provides an overview of the simultaneous effects of ambient temperature and humidity on emissions of criteria pollutants and greenhouse gases. In this work, traffic simulation and emission estimation were conducted by the IVE model, using long-term meteorological data. The findings of the present study indicated that a combination of high ambient temperature and low relative humidity increases the emissions of NOX, SOX, PM, CO2, and N2O from gasoline engine passenger cars. In contrast, when the average hourly temperature and humidity are maximum and minimum, respectively; The emission of CO reaches its minimum value. In conclusion, changing the working hours of offices and educational centers in such a way that the end of the working hours does not coincide with maximum temperature and minimum humidity, can be considered as a solution to reduce the vehicular emissions of criteria pollutants and greenhouse gases.

Street safety training is one of the many awareness programs that are often discussed around the world. Road accident statistics are on the rise due to lack of exposure to education and guidance awareness. Children are one of the most vulnerable groups in traffic accidents. Children are not easily able to get to know the surroundings, especially when crossing paths. This study has attempted to improve safety awareness among children using computer games as a learning tool, and in particular to develop their knowledge of the rules and conditions of the street after children use these tools. Computer games are good ways to teach safety on the road because of the interactivity with children. In addition to questions related to traffic laws, their attitudes towards road safety have also been assessed. Descriptive analysis, mean and percentage were used to describe the contact information. SPSS was used for data analysis. The overall findings show that all respondents had positive feedback about online games as a safety education tool along the way. Interestingly, data analysis shows a significant difference in the amount of information children have before and after games. Future research is suggested to improve the accuracy of the process given the larger sample size of the sample and the broader scope given that the target children were preschoolers.