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The article focuses on research aimed at developing an empirical delay model for nonintersection median U-turns on suburban divided multilane highways. Potential operational and safety benefits of using the unsignalized traffic movements at median U-turns include improvements in the level of service of their intersections, reduction in travel time and potential reduction in crashes.

This paper includes a simulation-based analysis of non-stop traffic at isolated signalised intersections. A Min-Max traffic control method is proposed to replace conventional traffic signals and maintain a continuous traffic flow. The method applicability is tested by means of Discrete Event Simulation (DES) using AutoMod software package. A set of quantitative Measures of Performance (MOP) is used to demonstrate the benefits of the proposed method compared to conventional traffic signals. In addition to eliminating vehicles stoppages, simulation results of the proposed method showed improvement in the overall traffic flow by reducing vehicle average travel time, average delay time, and the average number of vehicles at the intersection. The proposed method can be adapted to suit other types of traffic intersections and flow patterns and conditions. [ABSTRACT FROM AUTHOR]

The purpose of this research was to develop a model for estimating roundabout delay as a function of the influencing traffic and geometric factors. Fourteen roundabouts were selected from different cities in Jordan. Circulating volume, entry volume, and entry delay were measured during peak and off-peak periods using video cameras. Data on geometric design elements including circulating width, entry width, and roundabout diameter were measured through field survey. An empirical approach was used to develop a delay model as a function of the influencing factors based on a time interval of 15 min. The analysis indicated that geometric variables have significant effects on the roundabout entry delay. The entry width has the greatest influence, whereas the circulating width has the least influence. A comparison between delay models produced using different time intervals showed that, as time interval increases, R[sup 2] increases. The SIDRA delay model was validated using the field delay data, and it was found that it overestimates the delay, especially at high delay ranges. The M/M/1 (random arrivals, random services, and a single service channel) queuing delay model was also validated using the field delay data, and it was found that it estimates delay with high variability, especially for high delay ranges. [ABSTRACT FROM AUTHOR]