International Journal of Transportation Engineering
Volume:8 Issue: 1, Summer 2020

One of the most important points in a supply chain is customer-driven modeling, which reduces the bullwhip effect in the supply chain, as well as the costs of investment on the inventory and efficient transshipment of the products. Their homogeneity is reflected in the inventory-routing problem, which is a combination of distribution and inventory management. This paper considers a multi objective IRP in a two-level supply chain consisting of a distributor and a set of retailer. This problem is modeled with the aim of minimizing bi-objectives, namely the total system cost and risk-based transportation cost. Products are delivered to customers by some heterogeneous vehicles with specific capacities through a direct delivery strategy. Additionally, storage capacities are limited and the shortage is assumed to be impermissible. To validate this model, the epsilon constraint method is used for solving the model. Since problems without distribution planning are very complex to solve optimally, the problem considered in this paper also belongs to a class of NP-hard ones. Therefore, a multi-objective imperialist competitive algorithm (MOICA) as a well-known multi-objective evolutionary algorithm is used and developed to solve a number of test problems. Furthermore, the computational results are compared to show the performance of the proposed MOICA.

The fine-grained soil including the problematic ones can cause many difficulties in project accomplishment. Settlement and swelling are among the problems of the fine-grained soils. The present study compared the effects of the polypropylene waste plastic (PWP) and glass fiber reinforced polymer (GFRP) on geotechnical properties of the clayey soils for the subgrade design. To this end, the PWP and GFRP were randomly mixed with the fine soils of different plasticity indexes in similar weight percentages (i.e., 0.25, 0.50, 0.75, and 1). Further, compaction, unconfined compressive, direct shear, and California bearing ratio tests were performed in both dry and saturated conditions, followed by conducting the falling head permeability test. The results showed that PWP and GFRP materials were effective in the swelling potential of the clayey soil. In other words, the swelling potential decreased by about 32% and 33% in both CH and CL samples when the PWP content increased up to 0.75% in the specimens, respectively. In addition, this potential decreased by 60% when the GFRP (0.75%) was added to the specimens. Also, bearing capacity and elastic modulus increased mixing PWP (0.75%) or GFRP (0.5%) in the clayey soils by high and low plasticity indexes. Therefore, the improved soils can be used to make a subgrade layer for the pavement.

Since driving behaviors are cross-cultural in nature, they are directly under the influence of the ethical characteristics and mentality of individuals. This reality dramatically connects the driver behavior studies to the study of the humanities. People's jobs can substantially affect their beliefs and legitimacy, which are two critical indicators that successively affect the social lifestyle. This study, for the first time, aims to investigate the effects of the indicators mentioned above and different careers on drivers' behavior. The study uses a mixed questionnaire tool that contains four main parts including demographic information, a modified Driving Behavior Questionnaire (DBQ), the Allport religious orientation scale and the legitimacy questionnaire. The purpose of the study is to investigate the significant relationship between high-risk driving behaviors and the amount of belief and legitimacy of people in different job conditions. Statistical analysis, including analysis of variance (ANOVA), was used for data analysis. A sample of people (n=103) who had the driving license in four groups of jobs (including university professors, students, teachers, private-sector jobs, public-sector jobs) completed the combined self-report survey. The results showed that the type of job has significant effects on one’s driving behavior. The public-sector jobs committed the most violations (mean value of 1.64 in a 6-point Likert scale), and students are ranked second in this respect; teachers and university professors have the least high-risk driving behavior. The results of this study can be applied to determine the primer policies of traffic education in different job sectors.

At some intersections, excessive queue lengths may spill out of the left-turn bay and block the through lanes, jeopardizing level of service for the entire intersection. One of the most effective plans recently presented by the researchers is the "Contraflow left-turn lane" (CLL) In this method, left-turn vehicles will use the nearest lane in the opposite direction in addition to the usual left-turn lane. The most important principle in this design is that all vehicles which go into the opposite direction for left-turn movements should be definitely discharged during the left-turning phase. This issue prevents vehicles from a head-on collision when the other traffic signal turns green. Therefore, the number of vehicles entering the lane should be limited by a traffic signal. Accordingly, in this study, while determining the left turning capacity of the intersection with the CLL design based on vehicle traffic with generalized Poisson distribution, optimal CLL length and appropriate timing of the incoming traffic signal were determined. The goal of this study is to examine the effects of the CLL design on intersection performance. Therefore, the simulation of three real intersections in AIMSUN software was performed in two conventional and CLL designs. Comparison of the simulation results of the two designs showed that the CLL design at the intersections while reducing the travel time by 6 to 16 percent, resulted in an 8 to 24 percent reduction in vehicle delay. Also, according to the results of the study, the CLL scheme increased the number of stops for vehicles from 7 to 18%.

This paper concerns the problem of decision making on the selection of public transportation modes. The problem is formulated through sustainability indicators and the objective framework is based upon AHP-TOPSIS. In this research, the city of Isfahan (Iran) is our case study. The definition of different points of view was developed through interviews to stakeholders, experts in transportation and urban planning as well as end-users. In this regard, feasible alternatives of public transport modes, such as Metro, Tramway (Light Rapid Transit) Bus Rapid Transit (BRT) and Regular Bus (RB) were compared for demand corridors with similar characteristics and operating conditions. Besides, different aspects and criteria of sustainable transportation including economic, social and environmental dimensions are taken into consideration. Our findings address different orders of desirability and the suitability of public transport modes. In the view of end-users, Metro and Tramway are the most desirable modes due chiefly to service quality factors such as minimal travel time and comfort-ability. However, the local government is more interested to reduce total costs and therefore, the recommended alternatives are BRT and RB. To consolidate these results, an interview is conducted; city council members as well as senior experts in traffic and transportation fields are surveyed.

Nature is characterized by its chaotic behavior. Mathematics is considered one of the appropriate tools to achieve the best definition of possible its chaos variables and process. Classical mathematics deals with the numbers as static and meaningless, but chaos mathematics deals with it as dynamic evolutionary, and value- added. This paper attempts to introduce the transportation problem representation in chaos environment and also the necessity of the model is investigated. An approach for determining the chaos best solution is proposed briefly. The advantage of the proposed approach is accomplished with the associated ordinary number and the number of iterations arriving to the best solution is reduced. A numerical example is given to illustrate the utility, effectiveness and applicability of the approach for the problem.