فصلنامه جاده
سال بیست و یکم شماره 3 (پیاپی 76، پاییز 1392)

Aviation transportation is considered as leading industry and impressive on promotion in each country and its situation is of the main indicators of country development. The present research is aimed at feasibility study and analysis on establishing low-cost Airlines in Iran. Rendering the services with low costs and good prices¡ the low-cost Airline tries to attract more customers in a fairly competitive market with open and activating regulations through different strategies and omission of extra costs. As the main topic of the research¡ the business models of servicing¡ low-cost and charter Airlines were investigated and explained. Based on the made investigation¡ three key factors of aviation transportation were regarded and questioned: service rendering system during flight¡ sale department and Airline structure. After preliminary studies and using the library resources¡ two researcher-made questionnaires were applied¡ one of which allocated to passengers and the other specialized for managers and experts. These forms were prepared in order to make the practical investigation and gather the required data. Based on the research findings¡ it is feasible to create the low-cost Airlines in Iran via structural changes and providing the appropriate culture. This will increase the flight routes and consequently more passengers will travel through Aviation transportation..

Safety is known as the most important factor in performance of any kind of transportation systems. Therefore all transportation related agencies on all levels of governments focus on the importance of safety. Regarding this focus on a safe transportation system, safety is supposed to be considered in every aspect of decision-making and planning process of any agency appropriately. Relation between safety and urban planning is one of important aspects of safety. this study based on data collected by police is aimed to do needed statistical tests to find out whether there is a relation among urban crashes variables such as manner, place, severity, and day of crash occurrence or not. Then the results which show a macro level model of these crashes can be used to determine priorities and the way of dealing with urban highways safety concerns. High probability of pedestrian involved crashes in bollards in comparison with other places in cities is one of the results.

Sever impact on pedestrian in road accidents caused known them as the most vulnerable group in roads users, and more immunization must be attention to save them. Lots references has focused on pedestrian safety and presented immunization methods. One of the useable methods which is most impressive on pedestrian safety in at-grade intersection is safety equipment utilization. In pedestrian crossing passages are incumbent to know effective local parameters like pedestrian ages, walking speed, intersection geometry condition and etc. which cause select more proportional methods at there. So, a method presence which can guide traffic experts to find optimized immunization approach based on experiments is able to reduce decision mistakes. In this article, after study on pedestrian crossing immunization, introduced a new method to select best solution on pedestrian safety based on local condition. Universality and increasing decision reliable are the most advantage of this approach.

Characterization of hot mix asphalt (HMA) to evaluate and predict its performance in different environmental conditions and loading rates has long been of interest. Due to the viscoelastic nature of bituminous mixtures¡ the use of dynamic modulus (|E*|) as a measure of mixture stiffness -as a function of loading rate and temperature-¡ has recently replaced the previous assessment in terms of Marshall Stability and resilient modulus (MR). Therefore¡ it is essential to develop experimental and empirical relationships between available collected data and dynamic modulus test data in order to design according to new valid international guides.
This study is an attempt to introduce the concept of dynamic modulus and the factors affecting it as well as the methods of estimating dynamic modulus based on other parameters.

Investigation about rock slope stability is one of the main issues in the field of rock mechanics from the past until now. On the other hand, there is less rocky environment without parallel or transcend joint sets, and jointing is one of the main features of rock masses. Failure mechanism as well as safety factors of rock slopes is affected by jointing conditions, geometric properties of slopes and rock material properties and strength of joints. Obviously, how to deal with these slopes and stabilization of them depends on the recognition of their behavior. In this paper, it was used, discrete element method and UDEC to examine the effect of geometric parameters of slope and joint sets, as well as rock masses mechanical parameters on the stability of jointed rock slopes stability, in the planar failure mechanism. In accordance with the results, between the geometric parameters of slope and mechanical parameters of rock mass, the first one, i.e. slope height and the dip angle, has a special significance in slope stability, in terms of safety factor, and failure surface. For example, in the low slope angles, the failure is planar and passes through the discontinuity surfaces, and with increasing the slope angle, the failure surface change to a curve and passes from the rock material. Mechanical parameters of materials and joints are almost equally effective in safety factor variation. By improving and increasing joint mechanical parameters, the failure surface passes from the rock material, and with weakening of them than mechanical parameters of rock materials, the failure surface passes through the discontinuity surfaces.