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Several factors are usually considered when recommending left-turn phasing at signalized intersections: the volume of through traffic opposing the left-turn maneuvers, the volume of left-turn traffic, the speed of the opposing traffic, sight distance, crash history, and cycle length. The goal of this paper is to find the optimal signal phasing designs that can improve efficiency and safety of the particular signal design in the field in order to test current recommendations and guidelines on left-turn treatments. The researchers assess the impact of the number of rings in a phasing structure, the number of phases and whether to adopt lead or lag phasing on the safety and efficiency of a four-legged signalized intersection. A comprehensive set of 338 signal phasing designs is developed and the impacts are modeled using VISSIM microsimulation. The efficiency of signal phasing sets is evaluated in VISSIM, while the safety aspect is assessed using SSAM software. Optimal scenarios are tested using sensitivity analysis for various traffic flows. The findings show that the current left-turn guidelines may over-protect left-turners which results in reduced efficiency and left-turn delays that can be increased by up to 25%. Revised guidelines should contribute to the decreased delays for left turning vehicles, while keeping the safety standards high. [ABSTRACT FROM AUTHOR]

To promote solutions of key fusion problems like tritium retention and wall erosion, more measured data of carbon deposition in remote areas of fusion devices are needed. These data are essential to understand and model local and global particle fluxes and to make predictions for future devices like ITER. In spring 2000 the development of a new diagnostic, quartz microbalance (QMB), was started to measure quantitatively, in situ and time resolved (≤1 s) the material deposition in the sub divertor region of JET. Calibration work of mass and temperature characteristic was done at FZ-Jülich giving a layer mass sensitivity of Γmass=7.5×10-9 g/Hz and a temperature sensitivity of Γtemp(100 °C)≉0.09 °C/Hz. The commercially available QMB technique was adapted to the harsh constraints and requirements of JET. After implementation in March 2002 reliable and successful operation was demonstrated during the C5 campaign (∼1000 plasma pulses). First examples of measurements are presented. [Copyright &y& Elsevier]