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Project participants are becoming more aware of the high costs and risks associated with delay claims and their litigation. Among delays, weather delay has an important role in projects performed in severe environmental conditions. This research is the extension of delay analysis techniques by approving analysis of weather delays using fuzzy logic. At the presented technique, first using a fuzzy logic model calculated the delay that occurred during the activity execution after weather event then by the selected delay analysis method (Time impact analysis) and using the risk of the contractor during the contract approval together with the effect of previous delay in changing the duration of activities, analyzed weather delays in construction project. A local general contractor and governmental firms involved in a highway construction project practiced by offering their experienced and knowledge in delay analysis procedures to provide data for development and testing of the model specified for rain events. The results indicated that the presented model is in accordance with practical experiences in weather delay duration except in some circumstances that can be divided into the separated parts. It also advances the use of fuzzy logic in delay analysis procedures and becomes it more systematic special for weather delays.

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Delay is one of the principal measures of performance used to determine the Level of Service (LOS) at signalized intersections and several methods have been widely used to estimate vehicular delay. Very few studies only have been carried out to estimate delay at signalized intersections under mixed traffic conditions prevailing in developing countries like India. In the present study, various problems associated with delay estimation under mixed traffic conditions in a developing country (India) and the methods to over come them were discussed and an attempt was made to improve the accuracy estimating the same. Five isolated signalized intersections from a fast developing industrial city located in TamilNadu, India were chosen for the study. Site specific PCU values were developed considering the static and dynamic characteristics of vehicles. Saturation flow was also directly measured in the field for the prevailing roadway, traffic and signalized conditions and expressed in PCU/h. Control delay was also measured following HCM 2000 guidelines. Later, this was compared with that estimated from the theoretical delay model. Even after taking several measures, good correlation between observed and predicted delay could not be obtained. Therefore, in the present scenario field measured control delay was taken into account to define LOS. A new criteria for Indian cities recently published in the literature was used to assign LOS grades of study intersections and found to be better reflecting the field conditions.

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A robust periodic train-scheduling problem under perturbation is discussed in this paper. The intention is to develop a robustness index and propose a mathematical model which is robust against perturbations. Some practical assumptions, as well as the acceleration and deceleration times along with periodic scheduling in addition to a practical new robustness index are considered. The aim is to obtain timetables with minimum travelling time that are robust against minor perturbations while the unnecessary stops are minimized. Generally, the spread of delays in the railway system is called delay propagation. We show that in addition to this phenomenon, there exists a more complicated case in periodic type of scheduling that is the fact of delay propagation from one period to the next. In fact, if the delays of a period are not absorbed by the next one, the size of delays may converge to infinity. We name this as delay intensification. Furthermore, we develop a hybrid heuristic algorithm which is able to find near optimal schedules in a limited amount of time and can absorb perturbations. To validate the algorithm, a new lower bound is introduced.

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One of the frequent aspects of lawlessness at signalized intersections is red light violation (RLV). In addition to adverse effects on intersection safety, RLV can cause delay in the startup of the vehicles in the competing phase, defined as the green flow in this study. In this research a video camera was used to collect the required data from intersections in order to investigate the adverse effect of RLV in the city of Esfahan, Iran. Then, by assigning a cellular network to the conflict points of the vehicles path in successive phases the vehicles arrival times to these cells were measured and the imposed delays to the green flow were measured. The results of this study showed that the behavior of drivers in the green flow, the time passed into red interval, and the presence of an all-red interval are the prominent factors affecting the delay caused by RLV. Furthermore, in the absence of an all-red intervals a delay in the range of 1 to 4.5 seconds was inflicted on the subsequent competing green phase. Results of the study also showed that the amount of delay increased substantially when a RL violator was not permitted to precede through the intersection by the green flow vehicles.