فصلنامه مهندسی حمل و نقل
سال هفتم شماره 3 (پیاپی 27، بهار 1395)

In this paper a novel fuzzy driver assistant system is introduced which takes advantage of the information provided by vehicular communications. In the proposed system, each vehicle receives some information such as speed, density and drivers’ violation status from the vehicles in its vicinity. Then the danger level of each neighboring vehicle is evaluated by means of a fuzzy decision system. Finally the system suggests appropriate actions to improve safety of the vehicle. The proposed system also can be used for making lane changing maneuvers (such as overtaking, turning to left and turning to right) safer. Results of extensive simulations show that our driver assistant system decreases the number of potential accidents by 60%. Moreover, the number of accidents caused by overtaking, turning to left and turning to right is decreased by 77%, 74% and 82% respectively.

To protect environment and reduce the consumption of energy, warm asphalt technology has been used widely in recent years. There are different technology to produce warm mix asphalt. In this research Zycotherm nano material and Sasobit, which are respectively chemical and organic additives, as two sorts of warm mix asphalt construction trends were investigated. Although having many advantages, moisture susceptibility and rutting performance are two major concerns about warm mix asphalt that was investigated in this study. The functional characterization of the base bitumen with and without Zycotherm was analyzed by means of Fourier Transform Infrared Spectroscopy (FTIR). Overall, fifty four hot and warm mix asphalt mixtures were made. In order to check moisture susceptibility, Indirect Tensile Strength and resilience modulus tests, and to evaluate rutting potential of the mixtures, dynamic creep test were conducted. Results showed that Zychoterm nano material, in addition to the reduction it causes in mixing and compaction temperature, also improves moisture susceptibility of mixtures compared to control mix and the mixture with Sasobit. On the other hand, Mixtures with Zycotherm nano material had lower flow number than HMA and Sasobit mixtures, Generally reduction in temperature leads to less oxidative and subsequently to less rutting resistance, however, as it was expected because of the stiffer Sasobit modified binder, WMA mixtures containing Sasobit had significantly higher resistance to rutting than other mixtures.

In Transportation Master Plans (TMP), the detailed socioeconomic data of study area population are needed for forecasting travel demand. However, in Household Travel Survey (HTS), these data are collected only for a small sample of households. Since collection of such data for the entire population is too expensive, if not infeasible, it is necessary to produce synthetically such data using the macro-data of the population and micro-data of the sample. This process is known as population synthesis in the literature or as data expansion in Iran. It seems that the existing method of expansion did not result in valid assignment volume and trip matrix. Hence, a linear programming model is proposed for data expansion, which used variables at the household and individual levels simultaneously. This method estimates weights for households while minimizing the deviation of synthesized population socio-economics from observed ones obtained from census bureau. The comparisons between the results of the two methods (that are applied for the city of Mashhad) show that the coefficient of determination between the observed and estimated population of zones for the existing and the proposed methods are 0.79 and 0.97, respectively. Also, the proposed method resulted in a valid trip matrix and assignment volume. The percentage errors of screen lines daily volume are 25% in the existing method, whereas they are less than the acceptable 14% error in the proposed method. Root mean square error (RMSE) of links volume are 55% and 26% in the existing and the proposed methods, respectively.

In this article the severity of 661 crashes on roundabout in Tehran - Iran for two consecutive years (2012, 2013) were investigated for finding the effective factors on severity of crashes, their injuries and the relation of these factors with existing scientific knowledge using Logistic regression and Probit regression models. The kind of road users, light condition at night, condition of road surface, Average daily traffic, and the daily average of number of motorcycles, the daily average of number of pedestrians, mode and angel of collision were identified as the most significant effective factors. In this article AIC standard (Akaike Information Criterion) and McFadden R square statistic tests were used for goodness-of-Fit of models. With using the model and roundabout which their data were available, the validity of model were evaluated. At the end two built models have been compared and factors affecting the severity of crashes at roundabout have been introduced.

In this paper, a new mathematical model is presented for an open vehicle routing problem (OVRP) that maximizes drivers’ satisfaction and minimizes a number of vehicles simultaneously. One of the new problems related to the VRP area is the OVRP that is a new variant of the VRP. In the real world, because of decreasing the related cost, the vehicles should return to the depot after serving the last customer’s location, as the OVRPs do. It is proven that the classic models in VRPs belong to the category of NP-hard problems; thus due to its complexity using exact methods in large-scale problems, a meta-heuristic method based on multi-objective evolutionary algorithm based on decomposition (MOEA/D) is proposed and the associated results are compared with the results obtained by a multi-objective particle swarm optimization (MOPSO) algorithm. The results show that the proposed MOEA/D outperforms the MOPSO. Finally, the conclusion and further research are provided.

Cycling as an environment friendly mode is one of the urban transportation systems that are highly encouraged by sustainable transportation planners. During the past decades, promoting the cycling system has been considered in a number of cities in develop European countries. For instance, cycling is a responsive mode for more than a quarter of trips in the Netherlands cities. Today, a number of transportation demand management measures are focused on promoting cycling system such as spreading exclusive bicycle lanes, developing parking facilities for bicycles and developing bicycle stations. Tehran, as the capital and most populated city of Iran, is suffered from two main problems which are traffic congestion and air pollution. Since the latter is an outcome of the former, Tehran is one of the most polluted cities of the world. To cope with aforementioned problems, promoting the cycling system and encouraging individuals to use this mode is focused by transportation policy makers of the city. In this study, a behavioral model has been developed to show the effect of cycling related measures on the bicyclists’ mode choice behavior. Adopting a logit model, this study presents the effective factors that influence cycling including demographic characteristics, trip characteristics and cycling system characteristics as well as their marginal values.

Geometrical and topographical constraints are of the most important difficulties against the implementation of the high speed railways. This paper examines the possibility of establishing a gradual-based strategy for speed enhancement of the existing railway lines, in the areas with design constraints. Accordingly, an incremental methodology is proposed in which a railway line is divided into the various segments with different sub-regional conditions. This strategy is used to improve the speed, capacity and to reduce the travel time. The Tehran-Miyaneh railway line is selected as a case study, that with problematic geographical circumstances. The empirical Davis equation is used to determine the capacity of the railway line in which the capacity is defined in terms of the maximum number of trains that can pass from a particular rail section. The design speeds and capacities of different blocks are calculated for the selected case study. Considering the priority of the critical blocks, the enhancement of capacity and speed is studied for the case study. The results of operational conditions are obtained for the enhancement scenarios and compared with that of the basic scenario. The relationship between capacity and travel time is determined and compared for various speed intervals. The capacity of the route is increasingly enhanced by the incremental speed enlargements in different scenarios.

Transportation dedicates remarkable part of national gross production in every countries and a large part of fuel consumption occurs in this sector. For this reason, in recent years, many attempts have been made to reduce fuel consumption in vehicle routing problem. Vehicle routing problem is one of the important management problems in logistics and distribution basis. In this paper, factors affecting fuel consumption of vehicle routing are comprehensively discussed and by taking into account of factors such as vehicle load and velocity, distance traversed, road gradient and urban traffic congestion, fuel consumption optimization of vehicle routing problem is considered. For this purpose, Due to the factors mentioned, a non-linear mathematical model is presented to reduce fuel consumption. Considering to this issue that proposed problem is NP-hard, to solve the proposed model, an improved firefly algorithm is presented and compared with standard firefly algorithm. By improving the solutions about 2.5% in average, the results demonstrate the efficiency of proposed algorithm. Furthermore, the new model causes reduction of fuel consumption about 13% in average for samples. Finally a distribution company in Isfahan is considered; results show about 15% reduction in fuel consumption.

The Pavement management system can be seen as a process that is attempting to reduce the life-cycle costs of the road network over time. Meanwhile, the optimal scheduling of maintenance treatments plays a significant role in decreasing agency costs. This paper proposes an approach for road maintenance programming that uses multi objective optimization. This model has been used with a case study involving the Boeein Zahra Saveh road network, a district of Iran. Pavement performance prediction also modeled as a Markov decision process. In this article, we evaluate two objective functions: (1) minimizing the total agency costs; and (2) minimizing the road user costs. Based on the optimal scheduling, the agency costs and user costs are estimated to be 21.5 and 13534 billion Rials in the entire planning horizon, respectively. This indicates that the user costs are much greater than the agency costs user costs are. Therefore we should consider the user costs in the management decisions. The result shows that preventive maintenance has more effect on decreasing the user costs compered to the asphalt overlay. Furthermore, the results from this model show the amount of MandR cost in the early years plays a significant role in decreasing agency costs. In other word, they should allocate enough budgets for their activities in the early years.

A group of uses of central area of Isfahan, due to incompatibility with its neighbor uses and the area function, has important role on traffic and trip generation of this area. The present essay aimed at the determination of uses affected the rate of trip generation of the downtown(area) of Isfahan and calculation of coefficient of trip attraction for these uses has studied the effective factors on trip generation rate of this area and with calculation of the coefficients of trip attraction of these uses and also their shifts, it has replied to this question that which one of these uses has more effectiveness on generalization and attraction of trip of this area and also what is the effect of their shifting on the traffic of the area. For this purpose, twelve traffic zones forming central core of Isfahan city has been determined as the region under study and the data related to trips attracted for each of them were collected in six-class frame. The coefficients of trip attraction of uses were calculated by dividing the number of daily trips on each uses into area of that use; this coefficient proved that for each square meter of one use, how many daily trips are done .Then, using the standard of transportation engineers of America (ITE) which offers some factors as a suitable suggestion for all uses, the coefficients of trip attraction of uses in available state and recommended state were compared. The results showed that in all uses but medical use, trip attraction is very close to the recommended state and even it is more desirable in some cases .Also the results developed from effect of shifting medical uses to the outside of the area on traffic state were presented.

Asphalt pavements are damaged continuously due to premature failures and exceeded traffic loads. Among the various failures, moisture damage is the most widely spread failure in asphalt pavements. Sulfur extended polymer is a newly developed additive that is used to increase loading capacity of asphalt pavement designed. However, the role of these additives are purely investigated in term of their effect on moisture resistance of asphalt mixes. In this research by replacing 30, 40 and 50 percent of Googas (a sulfur extended additive produced in Mashhad, Iran), Marshall size specimens were prepared. Modified Lattman testing was performed on mixes and their Tensile Strength Ratio (TSR) parameter was determined on all mixes. The results showed that above additive cannot attributed on moisture resistance of asphalt mixes as its present status. In order to overcome this lack of resistance, a crumb rubber modified containing 20 percent rubber was replaced with the original 60/70 pen bitumen of the mix. repeating all ITS testing on the above mix combination with this new binder, it resulted in improvement of mixes (about 15 percent increase in TSR value). This exceeded the minimum requirement of TSR for asphalt mixes which could not be achieved neither with conventional mix, nor with those containing Googas and 60/70 pen graded bitumen.