نشریه مهندسی ترافیک
پیاپی 95 (زمستان 1402)

Development of urban road network is one of the common options to overcome the growth of transportation demand in congested urban networks. The problem of choosing the best combination of projects according to the budget limit is called the Road Network Design Problem (RNDP). In the classical solution of this problem, the travel time index is generally considered as the objective function, while other indices, including topological indices, are also effective in the quality of network service. In this article, the impact of the topological centrality index along with the travel time index on the network design is investigated, and the network design problem is solved by considering the betweenness centrality and closeness centrality indices at different budget levels for the Sioux Falls experimental network. Also, in this article, the betweenness centrality index is evaluated in the conditions of user equilibrium. The results show that minimizing the travel time index does not necessarily improve the centrality index. Therefore, considering the centrality index is effective in answering the problem of network design.

Nowadays, Internet taxis has become an important mode for people's daily activities and it can even be considered as a separate mode of transportation. In this research, the impact of internet taxi and personal car under Covid-19 is discussed. This study is done by designing the data collection process through questionnaire. This questionnaire was designed in the form of four parts and after collecting the questionnaires which was done online, 598 data were used for modeling out of 681 data after data validation and refinement. To investigate the effects of internet taxi on people's use of private cars under Covid-19, the multinomial logit discrete choice model (MNL) was used by the principal component analysis (PCA) method to reduce the dimension of attitudinal variables. Then the marginal effects were also calculated by simulation method. The results showed that under Covid-19, people use private cars more than internet taxis. In addition, people who have a PHD education degree use Internet taxi more than others under Covid-19 than private cars. In addition, the results of marginal effects showed that with the change of the city of residence from the small town of Birjand to the metropolis of Tehran, the tendency to use an internet taxi increases and the tendency to use a private car decreases.

Earthquake is a common natural disaster that often brings about wide-ranging catastrophic consequences. The post-crisis assessment of conditions generally indicates poor performance in evacuation routing and planning, leading to incoordination and waste of time and network capacity. Therefore, this study presented a heuristic, integrated solution to determine evacuation routes in the shortest time possible using an algorithm based on network analysis and the definition of safe nodes and arcs based on crisis conditions. The proposed flow optimization model employs MCNFP to find the shortest evacuation routes from each node to the safe zone and guide the maximum possible flow through this route. The model's efficiency was tested using 12 small networks with different combinations of nodes and vehicles and 10 medium networks with different numbers of nodes and similar demands. Then, the running times of each MCNFP algorithm and the proposed model (P-M) were compared. The results showed that the evacuation time increased by increasing the number of nodes and the routing complexity. In addition, increasing the number of vehicles in small networks increased the evacuation time. Finally, the research results confirmed the higher speed of the heuristic algorithm than MCNFP in network evacuation.

Nowadays, traffic congestion is a major problem in metropolises that affect daily life. Imbalance between supply and demand causes conjestion. Demand management is used to balance demand and supply, since has more reasonable cost and less restrictions in comparison with increasing transportation supply. One policy in order to manage the demand and reduce Tehran traffic conjestion is to implement flexible working hours since Mehr 1401. In this study, the effect of flexible working hours on traffic congestion has been investigated by using length of Tehran congested roads. The linear regression has been modeled based on the length of traffic congestion of the third week of Mehr 1398 before the Covid-19 epidemic in comparison with the third week of Mehr 1401. It was expected to face more road congestion due to the traditional education after the virtual education during Covid19 epidemic, user behavior changes, increase in usage of private cars. Nevertheless by implementing flexible working hours, Tehran traffic congestion has been far more suitable except the Limited traffic zone than the urban management's prediction.

One of the most important problems of urbanization is caused by the types of intra-city movement. Air pollution, traffic, sound pollution and mental and physical discomfort are some of the unfortunate consequences in this field. In this research, the factors influencing the decision-making of the citizens of Qazvin city in choosing a sustainable mode of transportation have been studied. Then, by using the discrete choice test method, people's decision to choose one of the sustainable transportation methods has been questioned through the questionnaire of the factors affecting citizens' trips with sustainable transportation methods. Safety was recognized as the most important factor for citizens. First, the results of the model in terms of their significance and then the final effects of each of the methods in the mentioned scenarios have been examined and the results indicate that 47% of people tend to choose a shared car, 24% tend to choose a bus, 19% tend to choose a bicycle and 10% tend to choose a walking method. Also, the willingness to pay has been calculated to improve each of the factors in this research, and it can be argued that parking and safety have a value of 0.065 and 0.06 respectively for people compared to the cost and travel time. It is more important.

The expansion of cities, the increase in their population and the increase in the ownership of personal vehicles have caused traffic congestion, environmental pollution, accidents, consumption of fossil fuels, etc. Applying transport demand management policies is one of the solutions to overcome these problems. The purpose of this article is to investigate and evaluate the effectiveness of several policies in the field of travel demand management, that is, car-sharing policies and the creation of HOV lanes in the city of Tehran. In this regard, rapid shuttle service has been proposed in the form of building 17 shuttle lines (origin-destination). First, the main high-demand origins and destinations and then the routes for running the rapid shuttle service, have been identified. Then, two scenarios, current statue and proposed scenario of constructing the shuttle service have been simulated and implemented in the macro model of Tehran to investigate and analyze the effects of the system construction. In order to compare the changes made in the road network of Tehran, indicators have been introduced, measured and finally compared with each other. The results of the study show that the total cost of the transportation system is reduced by 2.2% with the implementation of rapid shuttle service. The number of origin-destination trips of cars will decrease by 1.1%. The number of origin-destination trips with public and semi-public transportation system increases by 3.4 percent.

In recent years, research has been conducted on the adoption of autonomous vehicles and the environmental effects of this technology, but on the issue of the effect of utilizing autonomous vehicles on the share of urban vehicles in daily trips (through reducing parking space search time and share of urban vehicles in daily trips) little research has been done. In this research, the effect of autonomous vehicles system on parking space search time and the share of urban vehicles is discussed, and the effect is estimated by defining practical scenarios using a dynamic system model. In this research, after developing a flow diagram and simulating the system using two methods, model validity was evaluated. The model was used to analyze scenarios and estimate variations in important indicators. Based on the model results, the changes in the share of autonomous vehicles in daily trips show that different implementation strategies in utilizing autonomous vehicles and individuals’ preferences lead to change in the travel pattern.