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Numerous attempts have been made to improve the existing intersection systems to maximize capacity and reduce the delay costs and queues. This paper introduces a simulation method to study the effectiveness of a new technique introduced recently in China – the left-turn waiting area. This has an extended left lane that allows the vehicles to wait before the signal turns green. It is reported that this system can significantly improve intersection performance. This paper introduces the different types of left-turn waiting areas which have been widely implemented in China. The method of using micro-simulation VISSIM to study the effectiveness of left-turn waiting area is proposed in this paper, along with some preliminary results of a case study.

This paper introduced an optimization model to address dynamic speed control strategies for achieving network-wide speed harmonization. Genetic Algorithm (GA) was applied to search the optimal solution of the proposed model. During the search process, a computational fluid dynamics (CFD) based analytical model and microscopic traffic simulation VISSIM were applied to evaluate the performance of possible solutions. The proposed model can be used to determine the deployment of dynamic speed limits, the displayed speed limit, and the timing to change these speed limits. The proposed model was tested using VISSIM in an urban freeway network of about 12 miles long. Different simulation scenarios with varying AADT from 60,000 to 12,000 were tested. It was found that when properly implemented, dynamic speed control can improve traffic flow conditions, reduce congestion and emission, and enhance network throughput. For example, in the selected urban freeway network with the AADT of 80,000, the proposed dynamic speed control strategy can save 5% average travel time, reduce 9% of the vehicles with high collision risk and about 11% emission.

The objective of this study is to develop a microscopic simulation model to objectively compare operational improvements with capacity expansions. Simulation software VISSIM was used to redesign the existing facilities for the performance evaluation of operational improvement and capacity expansion strategies from delay time, emission and fuel consumption perspective. Two case studies were performed with different test beds to evaluate the effectiveness of performance evaluation model, majorly involving dynamic speed, ramp metering and hard shoulder usage strategies which are discussed in detail to illustrate the changes due to operational improvement and capacity expansion strategies.

Aurivillius phase ferroelectrics Ba(Bi1−xLax)4Ti4O15(x=0-0.05) (BBiLxT) was synthesized by a modified high-temperature solid-phase route.The structure, the dielectric, the ferroelectric and the aging properties were investigated systematically. With the La3+doping, the room temperature relative permittivity of the samples is increased, and dielectric loss is decreased. For the BBiLxT phase, only a weak variation with respect to the F2mm space group can be suggested from single crystal X-ray diffraction. The microstructure confirms the samples have a well-proportioned grain size and a higher density. The substitution also results in a marked improvement in the remnant polarization. The doping of La3+in BBiLxT ceramics increased the room temperature relative permittivity aging properties.