فصلنامه مهندسی حمل و نقل
سال پنجم شماره 4 (پیاپی 20، تابستان 1393)

Environmental impact assessment is a tool to ensure proper and correct implementation of a project and how it can determine، predict and interpret the effects of a proposed project on the environment. In environmental impact assessment process، the human judgments in decision making and in relation to selection type of land use، or measure the impact of development on the environment has been effective. In many cases it is necessary that the assessor with assessing the costs and benefits of different project alternatives، chooses the best alternative among competing ones. In this project environmental impact assessment was done، using Rapid Impact Assessment Matrix method، TOPSIS and ANP methods that are both methods of Multiple Criteria Decision Making. Process has been done، including: Screening، Scoping، The consideration of alternatives، Base line studies، Impact analysis، the impact assessment with three methods was mention above، Reporting. In the screening stage using positive lists (lists of covered projects)، it became clear that the project is to assess requires. Then، with field work، study area boundaries and the routes that has capable for constructing belt were determined. At this stage، two routes for road construction were introduced. Then the existing status of environmental factors was evaluated and use of experts and interests، environmental impacts were predicted، after that، the factors that were affected by construction belt were identified and as a criterion in environmental impact assessment were selected. Then using Rapid Impact Assessment Matrix method، TOPSIS and ANP، environmental impact assessment was carried out separately. All three methods the alternative «A» was introduced as an appropriate route for road construction. But the ANP method for creation of a network، capability in modeling the interrelationships between the criteria and alternatives at the levels and different aspect، is an appropriate multi criteria method for environmental impacts assessment of various projects which was introduced.

This paper considers a periodic vehicle routing problem (PVRP) with time windows in a competitive environment. In a real-world environment، there are several competitive distributers exist between them in order to access to customers earlier than other distributers to gain more market share in a minimum travelling cost. In this paper، a mathematical model for this situation is presented that minimizes the travel cost and maximizes the market share simultaneously. Due to the complexity of this problem، it is so difficult to optimally solve it in a reasonably computational time by exact methods. Thus، two meta-heuristic algorithms are proposed based on simulated annealing (SA) and improved simulated annealing (ISA). In addition، to show the efficiency of the proposed algorithms، a number of test problems are solved and the obtained results are evaluated with the result obtained by the Lingo software. Finally، the associated results are analyzed and the conclusion is presented. Furthermore، with increasing in dimension of the problem the running time of the meta-heuristics increases linearly. However، the running time rises exponentially in the exact algorithm. In large-scale problems، SA performs 20% better than ISA but the quality of the solutions obtained by ISA is 3% better than the SA algorithm. Furthermore، the maximum improvement made by ISA in comparison to SA is 7%.

Nowadays، air pollution in metropolitan areas is threatens people’s health. Considering severe decrease in cities’ air quality and dangers of such pollution for people’s health، recognition of the aspects of this problem is of great importance. Within urban areas، congestion flow is the most important factor in air pollution. Therefore، management of urban traffic network can impressively reduce environment contaminants. With regard to the significance of this problem and the complexity of relationship between traffic and emissions، traditional tools of traffic engineering cannot analyze traffic network flow. This research investigates the flow of traffic and the air pollution made by one of the traffic networks in the 7th region of Tehran municipality. Using AIMSUN software، this network is simulated and the effects of Heavy Vehicles on the emission concentration، travel time، delay time، stop time and average speed of traffic flow are analyzed and recorded. The results show that the average increase rate of، ، PM and VOC are respectively 11%، 121%، 12% and -35%. Furthermore، travel time، delay time، stop time and fuel consumption are increase due to Heavy Vehicles.

To prevent fatigue failure on long-life asphalt pavement، it is important to consider endurance limit in design. The endurance limit is defined as the tensile strain below which no fracture or fatigue damage occurs. Review of the literature shows that it is very time consuming to conduct fatigue tests at low strain. One of the major reasons for increasing of test time is self-healing. Beam fatigue tests results at low strain show that the stiffness and dissipated energy remains almost constant with increasing the repeated load number in the early part of test In this research study، to reduce the testing time and self-healing effect، it was proposed that the tests be conducted using loading at 25 Hz. Results showed that there is good correlation between fatigue lives based on loading at 25 Hz and 10 Hz. According to the tests results، two relationships were developed between fatigue lives based on loading at 10 Hz and 25Hz for normal and low strain.

In order to achieve the most complex forms of human behavior، especially to evaluate the performance and behavior of drivers when seeing the traffic signs، utilization of statistical methods based on sampling of the studied population، is one of the suitable ways for research in behavioral sciences. In this study، The CART algorithm as a non-parametric model and a sub division of data searching field has been used، where there is no need to user’s interference. In spite of the high applicability of this method in analysis of safety and accidents issues، the researchers have not paid sufficient attention to it، due to its high complexity. Drivers usually react differently in different conditions and circumstances. This study includes analysis of questionnaires distributed among 527 drivers. Results show that factors like the time of driving، the monthly income of drivers and their occupation، are quite important when their paying attention to traffic signs is under question. Factors like age and genre are not very important in seeing and paying attention to the traffic signs by drivers، although these are effective in creating accidents.

Bitumen is a Newtonian fluid at high temperatures but a viscoelastic fluid at other temperature ranges، that its linear viscoelastic area shows bitumen resistance toward traffic load. In this study، carbon nano-tube، as bitumen viscoelastic characteristics modifier، is employed. Then classical experiments of bitumen (such as: softening point، penetration and etc.. )، X- ray diffraction and rheological tests using dynamic shear rheometer (DSR)، also were done on modified samples. Using carbon nano tubes as bitumen modifier cause the significant improvement on classical properties of bitumen and also on performance characteristics of bitumen according to the base bitumen. Finally، by analysis the Master curves of complex modulus، loss modulus، storage modulus and phase angle، it is observed that viscoelastic characteristics of modified bitumen has improved significantly. With the increase of traffic and consequently، the loads applied on the roads، the need for a more durable pavement has gained special significance. Therefore، the researchers have been seeking to improve the functional properties of bitumen and asphalt. Nanotechnology deals with the creation and use of functional materials، devices، and systems with novel properties and functions that are achieved through the control of matter at the atomic and molecular level. Among various nano-size materials، carbon Nanotubes (CNTs) may represent the most promising modifier for the improvement of performance characteristics of structural and construction materials. CNTs have been extensively used as the reinforcing agents for high performance polymer composites. It has been reported that the incorporation of CNTs in the polymer matrix results in a significant improvement in the mechanical، electrical and thermal properties of the polymer matrices. Nowadays، a lot of rheological evaluations are carried out، polymer modified bitumen and the purpose of all، are the conditions that can simulate actual operating conditions of bitumen that equals to pavement condition.

One of the most significant issues in transportation planning is investigation of travel behavior in disaggregate or individual level. Analysis of university commuters’ route choice behavior is one of the subjects of travel behavior survey which is crucial in evaluation of existing transport infrastructures and assessment of future needs. In this paper، the main factors affecting route switching of university commuters are investigated in Tehran، the capital city of Iran based on trips purpose namely work trips and school trips. The designed questionnaire of route choice behavior was filled out by 528 commuters from 9 university-faculties in Tehran who used their own automobiles in order to travel from home to university. The commuters were asked whether they had switched their habitual route before or during their trips from home to university for the past three months ending up to the time of survey (June 2012). Binary logit model was calibrated for this route switching behavior. The results of school trips model illustrate that older students tend to switch their routes more than younger ones. Moreover، the variables NAR (number of alternative routes)، NDH (number of driving hours per day) and NSI (number of signalized intersection) have more statistical significance in relation to other variables used in the school trips model. Also، the results of binary logit model for work trips show that men tend to switch their routes more than women. In addition، among faculty members and staff، the rate of route switching decreases with the increase of route safety in terms of number of traffic conflicts and accidents.

In this study، the stiffness and fatigue properties of asphalt concrete mixtures، modified by waste plastic bottles (PET) have been evaluated. Different amounts of PET (2% up to 10% by weight of bitumen) was added by dry process to the mix and the resilient modulus and fatigue tests at 5 and 20 °C were performed. The results showed that low amount of PET (up to 2% by weight of the bitumen) increases the stiffness and results are then descending. It also tends to harden the asphalt mixture at low temperature، the addition of PET to reduce its hardness. At high amount of PET (especially 8% and 10%)، fatigue life of mixtures increased more and the relationship between fatigue life and initial strain shows that at high loading conditions، fatigue failure will be more critical، at low to moderate temperatures. On the contrary، at lower loading conditions where the strain values are less than about 160–210 microstrain، the fatigue failure is not critical at low temperatures.

Increasing trend to use railway transport as one pillar of transporting passengers and goods in one hand، and daily reduction of available oil resources and as a result fuel reduction and also solving of pollution environmental problem in other hand illustrate importance of more studies and researches in this domain. Due to optimized energy consumption in railway industry that is very important، we can use optimization algorithms. One of intelligent and capable algorithms in optimization problems is Particle Swarm Optimization (PSO) algorithm as one of the newest optimization algorithms. Besides suggesting a comprehensive model of train movement dynamics and its fuel consumption، a novel and applicable method to save energy using PSO algorithm has also been suggested in this paper. To illustrate the proposed method more clearly، some applicable scenarios with their simulation results are considered and analyzed during the study. At the end، some worthwhile suggestions for future researches are presented.