Browsing by Subject "Cellular automata"
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Item Cellular Automata for Traffic Flow Modeling(Center for Transportation Studies, University of Minnesota, 1997-12) Benjaafar, Saifallah; Dooley, Kevin; Setyawan, WibowoIn this paper, we explore the usefulness of cellular automata to traffic flow modeling. We extend some of the ex.isting CA models to capture characteristics of traffic flow that have not been possible to model using either conventioinal analytical models or existing simulation techniques. In particular, we examine higher moments of traffic flow and evaluate their effect on overall traffic performance. The behavior of these higher moments is found to be surpri, ,lg, somewhat counter-intuitive, and to have important implications for design and control of traffic systems. For example, we show that the density of maximum throughput is near the density of maximum speed variance. Contrary to current practice, traffic should, therefore, be steered away from this density region. For deterministic systems we found traffic flow to possess a finite period which is highly sensitive to density in a non-monotonic fashion. We show that knowledge of this periodic behavior to be very useful in designing and controlling automated systems. These results are obtained for both single and two lane systems. For two lane systems, we also examine the relationship between lane changing behavior and flow performance. We show that the density of maximum lane changing frequency occurs past the density of maximum throughput. Therefore, traffic should also be steered away from this density region.Item Development and Application of On-Line Strategies for Optimal Intersection Control (Phase III)(Minnesota Department of Transportation, 1996-10) Kwon, Eil; Stephanedes, Yorgos J.; Liu, Xiao; Chidambaram, Sabhari; Antoniades, CharalambosThe previous phases of this research reviewed and tested existing intersection control algorithms in a simulated environment. Further, a machine-vision detection system with four cameras was installed at the intersection of Franklin and Lyndale Avenues in Minneapolis, Minnesota, to develop a live intersection laboratory. Phase III enhanced the live laboratory with two additional cameras covering the intersection proper and the extended approach of southbound Lyndale Ave. A comprehensive operational plan for the laboratory was developed and a new microscopic simulator for the laboratory intersection was -also developed. Two types of new intersection control strategies, i.e., one with link-wide congestion measurements and the other based on neural-network approach, were developed and evaluated in the simulated environment. Further, using the data collected from the machine-vision detection system, an automatic procedure to estimate the intersection delay was also developed and applied to compare the performance of fixed-timing control with that of the actuated control strategy.