Homework_4

Homework_4 - Department of Civil Engineering CE4211/5211...

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Department of Civil Engineering Spring 2009 CE4211/5211 Traffic Engineering Dr. Henry Liu 1 Homework #4: Vehicle-Actuated Signal Control Due: April 6, 2009 Characteristics of Fully-Actuated Operation: In fully-actuated operations, all signal phases are controlled by detector actuations. In general, the minimum and maximum green times are specified for each NEMA phase. Maximum green does not begin timing until there is a serviceable, conflicting call (pedestrian or vehicle). In this type of control, cycle length and green times vary considerably from cycle to cycle as well as from time-of-day (TOD) to TOD. Certain phases in the cycle may be skipped entirely if no demand is present. Problem Statement Shown below in Figure 1 is a particular four-legged intersection being operated in a fully actuated mode. The timing sheet is shown in Figure 2. Shown in Figure 3 is the pattern of vehicle arrivals at the intersection; the time of each arrival is indicated by the symbol . In this figure, time is referenced to the system master (i.e., in “global time”). The row labeled “Initial Display” indicates the status of the signal display for the time period t < 51 secs for each NEMA movement; “G” Green, “Y” Yellow, “AR” All Red, “R” Red. Assume that these initial displays have been indicated for an indefinite time prior to t = 51 secs. On this same sheet it is also indicated the active status of the signal displays for all NEMA movements that result from the arrival pattern show in Figure 3. Also, we indicate in the column labeled “Action,” the controller operation that caused any
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This note was uploaded on 02/07/2012 for the course CE 4211 taught by Professor Preston,h during the Spring '08 term at Minnesota.

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Homework_4 - Department of Civil Engineering CE4211/5211...

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