پژوهشنامه حمل و نقل
سال سیزدهم شماره 4 (پیاپی 49، زمستان 1395)

Promoting people to use bus transport services leads to decrease using private cars and therefore decrease heavy traffic jam and airpolution. Promoting people to use the services needs to provide better services with lower cost. To achieve the goal, private operators must find innovative ways to provide the services. Providing the innovative services is not possible, unless the operators have freedom to make decision about tactical level decision (determining ticket rate and type, routes, vehicle type and timetables) besides operational level decisions. In other words, they design and operate the services themseleves. Operator freedom leads to emerge challenges like lack of route integration that create the problems and decrease popularity of bus services. In this paper, the challenges are collected by using published case study reports of various cities and conducting semi structural interviews with bus transport experts. The root causes of them are found by more investigations in the literature and interviews.
The results of the paper show that transfering the tactical level decisions to private operators successfully, transport authority as well as private operators should have some capabilities like, ability to control and monitoring and integrated information system. These capabilities are defined by using published case study reports and conducting interviews. Transaction between operators and transport authorities should be also simple and have an ability to codify into standards and codes simply. The definition of capabilities helps transport authorities to evaluate the required capability of the private operators and themselves to prevent the challenges before starting to transfer tactical level decisions to private operators.

With globalization and the massive growth in consumption worldwide, supply chain networks have changed to very large networks and the components of these large networks caused serious environmental problems. In traditional supply chain network design, optimization models are mostly single-objective and the aim is to minimize the cost of the network. In this paper, a new two-objective mixed integer linear model for closed-loop supply chain network design has been proposed that consider both forward and reverse flow to avoid sub- optimality. The proposed model takes all aspects of possible carbon dioxide emissions in the proposed supply chain network and considers a fair and reasonable balance between economic and environmental objectives are established. To illustrate the trade-off between the goals, epsilon constraint method has been used. To demonstrate the effectiveness and applicability of the proposed model, this study utilizes data owned from a case study of a copying industry closed loop supply chain. This paper can help managers improve the environmental performance of green logistics in the supply chain as a supplement strategy for the benefit of sustainable competitive advantage.

The importance of speed as the main index and characteristic of aviation compare to other forms of transportation seems even more sensitive issue when it comes to flight delays. Concerns over this matter became a motivation for special measures to be taken by different countries in relation to delay by creating uniform regulations in terms of cargo and passengers through planes. All these efforts lead to codification on the convention for unification of certain rules relating to international carriage by air, commonly known as the Warsaw convention of October 12, 1929. According to article 19 of the above convention, approved by I.R Iran, “the carrier is liable for damage occasioned by delay in the carriage by air of passengers, luggage and goods”. This liability can be limited and in cases disclaimer might be accepted as well while according to the convention, intensification of liability of aviation operators is not unmanageable. The remarkable point about the convention is its failure to adopt appropriate stance in case of flight cancellation or invalidation. Silence of the convention in this regard, while the cancellation of flight can tarnish the achievement of targets even more than the delay per se, forced countries to provide a solution in their internal rules using general rules of liability and ratification of restitution due to flight cancellation and also recognition of liability of aviation operators. Although the legal position of such guidelines toward international conventions which proved more protection for passengers in not clear, they impose heavy financial burden on airline companies.

In this study has been attempted to Investigate energy efficiency in transportation sector by using an index decomposition analysis approach IDA and LMDI method. In this method, at first analysis the Changes of energy consumption to it's effects and then by using intensity effect savings from improving efficiency is specified, then checked efficiency trend using energy performance index. Transportation sector due to use of the physical measurement indexes are divided to two subsectors: goods transport sector and passenger transport sector
Results in passenger transport sector, shows lack of efficiency in this sector. only in 2007, improving efficiency causes to positive savings in this sector.
In goods transport sector, despite of passenger transport in most years except for 2005 and 2008, efficiency has been increased and savings from increased efficiency has been positive.

Delay in recovering the speed of the vehicle results in occurrence of the hysteresis phenomenon in traffic flow the disturbance. The fundamental theories to analyze the hysteresis phenomenon based on driver behavior asymmetry during acceleration, and deceleration phases are open research area and need more developments. In this paper, which is the review of recent efforts in understanding hysteresis; using a Newell`s car following model, are reviewed to study the effects of different parameters on the magnitude of the motioned phenomenon. Moreover, the hysteresis phenomenon based on aggressive and timid driver behavior was identified. Microscopic sensitivity analysis and its results are shown by considering a conducted research based on the modeling of the phenomenon by neural network, and optimizing hidden layers of the neural network using genetic algorithm. Furthermore, in non-stationary traffic flow by using the kinematic wave model in variable wave speed; the magnitude of the hysteresis was estimated by a gradual analysis of the speed- density relationship. The results showed that the shape of traffic hysteresis loops depend onthe driving behavior. Also, Spacing and acceleration at the end point of the phenomenon are considered as the most effective parameters in the sensitivity analysis related to driver behavior. Last but not least, it was found that the hysteresis magnitude in the non-stationary condition resulted in the lowest amount.

Despite Airports importance as the main air transport infrastructure, few studies have focused on the analysis of airports in Iran. Researchers have evaluated the efficiency of airports using cross sectional analysis, but there has not been any study that evaluate the performance of the Iranian airports using Dynamic analysis. It is clear that for comprehensive performance assessment, cross sectional analysis is necessary, but this type of analysis does not cover all aspects of performance and Dynamic analysis should be used to achieve comprehensive results. This paper analyses efficiency of airports in 2013 through integrated DEA/AHP approach and Airports are ranked according to the results of this model. Then, the productivities of Iranian airports over the period of 2008–2013 are analyzed using the Malmquist index. The main objective of this, is to propose dynamic analysis for airport’s performance. The findings indicate that Ahvaz, Mehrabad and Mashad airport had higher performance Score Than other in 2013, and Abadan airport had the worst performance. But ] in terms of productivity growth, airports in Surrey, Yazd and Abadan, have experienced the greatest improvement in their performance during 2008 to 2013. Also, in terms of the Malmquist index, the average rate of productivity showed a slight improvement in this period of time, and the core engine of this was increase in technological efficiency.

Increasing reliability and safety of railway systems are of the most important goals of railway infrastructure managers which requires implementing more precise automated systems to detect defections. 90 percent of railway accidents in the Tehran railway occurs on switches, while 40 percent of which is due to careless maneuvering, 25 percent because of wrong track, 25 percent for switch defects and 10 percent for diesel car collisions in turnouts. Therefore, performance of switches is of great importance in railway tracks. Having made appropriate connections and proper track shifts, the system reliability can be substantially increased and incidents will be significantly decreased. This study consists of two main parts. Firstly, a switches and their importance in railway is studied. Secondly, switch blade monitoring using image processing is discussed. For this purpose, high resolution pictures are taken from switches with high quality cameras in order to detect defects. The algorithms used in this paper are based on clarifying the changes of blades for shifting the directions and allows for assuring switch locking.

The growing trend of accidents on roads and casualties and damage caused by such incidents result in loss and disinvestment of countries. So right investment and recognizing each of the three accidents (road, driver and vehicle), the principles expressed problems this causes and practical solutions can greatly reduce the occurrence of such incidents. One of the main problems of the country's road network of quality roads and thus increase the number of traffic accidents leading to death. In this article, were going to use cellular automata algorithms, to investigate the role of industry involved in road accidents decrement. Cellular automata algorithms can be very simple and understandable to the reader to form complex equations express. This collection includes: (supervision, materials, climate, road design, funding); Set the desired cellular automata (automata Road) at any time can have multiple states. In addition to the current state of each cell in cellular automata of road and neighbors can also be an effective influence of external factors which can be political pressure. One indicator of the number of accidents, the accident rate kilometers. The results in this paper suggest that there is an inverse relationship between automata road accident rates. Increasing of the efficiency of the factors involved in road building, reducing accidents leading to death. The impact of each factor on the amount of damage is variable. Using a simple study, we can achieve to this result that more spending for improving the roads can reduce the economic detriment of accidents and sometimes it costs less than the cost spent on compensation for losses caused to the families of death or injury crash. This article aims to strengthen the relevant institutions and effective partnerships is to improve the traffic system so that safer and more secure road system for pedestrians. Such partnerships should be as long as a cross between Ùvarious government departments and between different levels of government, as well as between governmental and nongovernmental organizations are to be established. The results showed that by changing the approach to increase the monitoring of road building, there is the possibility of reducing losses due to accidents.

Providing accurate prediction for public transport(bus) travel time is valuable for both operators and passengers. It helps operators to implement their strategies like , different fleet assignment in different times of day. It also helps the passengers to experience less waiting time and it will increase their satisfaction. Public transport travel time is affected by several factors such as, passenger demand, weather condition , traffic flow and etc. which all have to be considered to have precise prediction . however , previous studies are mostly concentrated on historical data-based models which uses temporal variables (time of day , day of week) as an input. Tis paper develops artificial neural network (ANN) models to predict bus travel time by using range of input variables including traffic flow data and passenger demand collected from a bus route in Tehran, Iran. The paper examines the proposal model by comparing with two alternative models. A historical data-based model which uses temporal variables and a traffic flow data-based model which only uses traffic flow parameters as an input. The results show that the proposal model outperforms other model in RMSE and MAPE index.

Sea transportation is the base of trading and plays a major role in supplying commodity chain. In this chain, Ports as the stimulants of economic activities of countries and connecting ring between land and sea transportation ensure the steady flow of goods and services and provide traders and owners with the economical way to exchange goods. Khorramshahr is one of the most important ports in Iran and is located in the northwest of Persian Gulf and southwestern Iran (Shalamcheh land border) neighboring southeastern Iraq and is located at the confluence of the Arvand and Karoon rivers in Khuzestan province. This study examined the effects of changes in fuel prices on sea freight in Khorramshahr port in order to determine the effectiveness level of each factor in changes of transportation costs .This study is based on annual data time series 1996 to 2012. The research results show that the ship's fuel price is directly proportional to the sea freight, the demand for sea transportation varies inversely with the increase in fuel prices are, fuel consumption rate is directly proportional to weight of transported goods (ton/mile) and increasing in the number of freighters varies inversely with sea freight.

Avalanches are of highly probable natural disasters on mountain roads during cold seasons. This natural phenomenon is also a usual reason of road closures and casualties in Iran especially in roads between Tehran and northern cities and western and north-western roads. In order to preventing or reducing avalanche incidents, first, more risky points should be identified and next, suitable safety actions must be considered. Previous studies mainly use regional and geological data based on field inspections, whereas, several other parameters are considered in this study and a combined model is developed. The parameters are snow depth, side slope, vegetation, avalanche frequency, vehicle collision possibility, daily traffic count, and expert interview. Ten avalanche-prone points are identified in Karaj-Chalous road and are prioritized using method of TOPSIS. The results show that avalanche frequency is the most effective factor. Moreover, the results show that sections of 62퍍63퍍, 63퍍68퍍, and 70퍍74퍍 are the most risky ones and safety solutions should be considered in these points.