فصلنامه مهندسی حمل و نقل
سال دوازدهم شماره 1 (پیاپی 46، پاییز 1399)

One of the main goals of the public transportation system is to create safe and easy travel conditions for all people in the community as well as to reduce the desire to use private modes of travel. In many cities, the current public transportation system does not provide such a situation for the disabled, because, in almost all public transport systems, there is no equipment for accessibility of the disabled (and in particular, wheelchair users). On the other hand, in order to increase the level of social justice between different groups of users of the public transportation system, adequate access routes must be made for the disabled, and also the public transport fleet must be equipped with special facilities for them. In order to evaluate the utility of different modes of transport in the event of accessibility for the disabled, it is necessary first to determine the role of factors influencing their mode choice behavior. In this research, the difference between two proportions and variance analysis statistical tests were used to determine the difference in behavior between different groups of the disabled. For this purpose, the individual and family characteristics of the individuals along with the mode of trips were asked for a community of 87 disabled people in Hamadan. Results indicate that the need for a wheelchair in travel, the number of family members and the ownership of electric wheelchairs have a significant effect on the selection of all modes of travel, while wheelchair ownership, income, sex and age are only effective in choosing some of the modes of travel. Also, the correlation analysis of independent variables does not show a strong linear relationship between them, while their correlation with the dependent variable is relatively strong.

Traffic safety is one of the main challenging issues in transportation engineering. Hhuman factor in most reports has also been announced as an effective factor in accidents. Various methods have been proposed for controlling and warning drivers in order to prevent violations. The methods can be classified into traditional and modern categories. Nowadays applying intelligent transportation systems are so popular, but deciding about their application is done often based on personal judgments. However, these systems have various benefits and disadvantages and each one must be applied in the proper case. In this paper we want to compare 4 scenarios containing 1- No control 2- Controlling by police 3- Applying cameras and 4- Intelligent transportation systems in the road. These scenarios are different in application, cost of application, precision and proportionality to the road classification. Here, a model for decision making based on 7 criteria and by Fuzzy Inference System would be developed. Then the proposed model would be tested for a case study in Kerman County for 5 rural roads. Results indicate that the proposed model can be a helpful method in order to decide about selecting the proper scenario to control the rural roads based on technical and economic criteria.

Earthquake ground motions may vary significantly at multiple supports of long structures such as highway bridges and dams, due to the incoherence, wave-passage, and site-response effects. Therefore, it is expected that seismic behavior of this type of structures would be strongly affected by the changes caused by the motion of the earthquake along the length of the structure. To investigate the seismic vulnerability of these bridges, fragility analysis is performed using spatially variable ground motions. To achieve this aim, this study chooses a set of 70 box-girder bridges considering mechanical and geometrical uncertainties and creates a numerical model of the bridges in OpenSEES software, which can account for the inelastic response of its multiple components. These models are assessed using two scenario of applying the ground motion, uniform and multi-support excitation. The results show that the fragility of these bridges increases with decreasing deck radius by more than 50% (depending on damage level and deck radius) and also with non-flexibility considerations, component vulnerability and bridge system more than 10% is more than a uniform excitation.

Vehicles always have been experiencing delay at signalized intersections. Research has shown that direct left turn movements (DLT) at signalized intersections increase the number of conflicts, and this may lead to increase the waiting time. To address this issue, unconventional alternatives have been proposed. One of these alternatives is using the U-turn movement at the midblock median openings instead of the DLT movement. In this research, the method of using U-turn followed by a right turn (UTRT) movement instead of DLT at three signalized intersections namely Takhti, Sheikh Sadoogh and Azar-Mellat in Isfahan in the presence of different volumes of left turn traffic was studied. At the first step, for the data collection, videotaping for one hour was done at each intersection at the peak hour. Then by using field study method, the geometric and traffic specifications were extracted. Having used Synchro software, the three signalized intersections were optimized in six different scenarios using different left-turn traffic volume and in UTRT mode in seven scenarios as well. Going further, using the optimized timing schemes, the aforementioned intersections were modeled in the Aimsun software in order to evaluate the traffic performance of the proposed method. The simulation results in the Aimsun showed that the use of UTRT alternatives instead of DLT movement, improved performance of the signalized intersections. Using this alternative ended in the reduction of the travel time at Takhti, Sheikh Sadoogh and Azar-Mellat intersections 76 to 85, 36 to 64, and 65 to 84 percent, respectively.

In the modern era, due to the shortage of natural resources and the damage of the environment, the benefits of recycling asphalt material is not negotiable. In this research study, the performance properties of asphalt mixtures containing 50% and 100% of reclaimed asphalt pavement modified with Cyclogen as rejuvenator and different percentage of glass-Polyolefine fiber (0.06%, 0.12% and 0.18%) was investigated. For this purpose, resilient modulus, moisture susceptibility and dynamic creep tests was conducted on the manufactured asphalt mixtures. The results showed that using rejuvenator led to decrease in resilient modulus, rutting resistance, moisture susceptibility criterion and indirect tensile strength of asphalt mixtures. However, the negative impact of the rejuvenator on rutting resistance, resilient modulus and moisture sensitivity was compensated by using fibers. The moisture resistance of asphalt mixtures was also improved by adding fiber in the mixtures. The optimum amount of glass-Polyolefine fiber in asphalt mixtures was determined as 0.12%.

This study considers a location-routing problem (LRP) with multiple depots and hard time windows for customers. The aim of this paper is to select optimal locations for depots and plan scheduling and routing of heterogeneous vehicle fleets. Therefore, it minimizes costs of establishment of depots and reduce transportation time by finding the optimum routs simultaneously. Customer satisfaction is important for each organization; hence, a hard time window is considered for customers. The main approach of this study is considered location-routing problem simultaneously for reducing location-routing costs and it work effectively. To validate the model, an augmented epsilon-constraint is used to solve small-sized problems. Because the problem is NP-hard, it takes too long time and needs too much space memory to solve large-sized problems optimally. Deterministic algorithms cannot solve the large-size problems. Thus, a well-known multi-objective evolutionary algorithm, namely non-dominated sorting genetic algorithm (NSGA-II), is proposed. Gap between augmented epsilon-constraint and NSGA-II show accuracy. The results are analyzed and compared in order to show the efficiency of the proposed NSGA-II.

Hazardous materials (Hazmat) transportation and emergency response during Hazmat incidents is a very important issue in transportation field. In this paper, a new bi-level optimization model for Hazmat transportation network design is proposed. The bi-level framework involves a regulatory authority (government) and hazmat carriers. The government (upper level) affects the carrier's decisions by locating Hazmat emergency response stations and Hazmat network design. The government aims to maximize the coverage of network routes according to available budget. The coverage of routes means responding to Hazmat incidents. The carriers (lower level) by deciding on Hazmat flows and selecting transportation routes, seek to minimize their travel cost. Using KKT condition, we reformulate the non-linear bi-level model as a single-level mixed integer linear programming one which is solvable by an optimization solver like CPLEX. Through computational analysis, different aspects of proposed model are investigated to evaluate the model performance. The results show that increasing in coverage radius and risk tolerance result in higher network responsiveness.

These days, emergency request responding in a short time is a highly challenging issue. The main goal of current research is modeling an optimization problem for emergency vehicle routing on small and medium-sized networks and solving the problem by a novice algorithm. The suggested algorithm inputs are the network, location and number of requests, vehicles, and hospitals. The objective is to minimize total travel time of vehicles plus the time that the last request is responded completely. The algorithm output is the vehicle and hospital assignment to each request and requests' responding order on the network. After developing the mathematical model of the problem, 138 random samples are produced on a network with 7 nodes and 16 links. The number of feasible answers, which is depended on the number of requests, vehicles, and hospitals, is tried to be reduced by assuming a fixed order for responding the requests. Hence, 3 different scenarios of request order are examined and it is found out that arranging the requests based on distance from the nearest vehicle results in better answers (lower total travel times). An innovative algorithm is presented for solving the problem which reduces the solving time to 5 seconds; while finding the precise answer needs time up to 810 seconds. The results show that the difference between more than 80 percent of answers found with the suggested algorithm and the precise answer is lower than 10 percent and this difference is less than 30 percent in more than 94 percent of the answers.

Given the increasing use of roundabouts in the design of intersections, it is important to examine the behavior and decision-making process of users in crossing the roundabouts. Investigating the injury crashes in 22 roundabouts of Mashhad city in 2014 and 1394 has shown that 41% of crashes are related to motorcycle riders.Therefore, in order to reduce accidents, it is necessary to recognize the causes and the process of the crash occurrence of motorcyclists For this purpose, in this study the crash data were evaluated based on the cause of the crash and the collision type of motorcycle riders to determine the most common causes and collisions. Then, to investigate the factors affecting motorcyclist crashes and inappropriate negotiations in the roundabouts, three models have been created including model of injury crashes frequency, model for predicting the percentage of inappropriate movement of motorcycle riders as well as the injury crash frequency model based on their inappropriate negotiations on roundabouts. The results show that the increase of three variables including entering traffic volume, input width and angle of roundabout deviation increase the accident rate, and increasing the width of the weaving part leads to reduction of injury crashes. Also, by increasing the exit widths and the turning traffic volume of the motorcyclist, the improper movements of motorcyclists increase. Increasing the roundabout angle deviation and the turning volume of traffic reduce the inappropriate movements of motorcyclists.