Lab 1: Passage Time and Detection

Objectives of this lab: (1) Calculate detector status from vehicle time stamps (2) Calculate detector gaps from detector status and vehicle time stamps (3) Determine what the controller response would be given a detector size and passage time (4) Understand the trade-off that exists between the two passage time purposes (5) Design the detector set back and passage time given a reasonable allowable gap

Overview You will accomplish the lab objectives using field data collected at the EB through lane of the Deakin Avenue and 6th Street intersection. Using this data, you can create a realistic representation of what a detector would output to a controller and determine the gaps that a controller sees based on the detector status. Once you determine what the controller can see, you can then create a simple representation of what it would do given a passage time setting. Connecting the concepts of what a controller sees to what a controller does will then enable you to look at passage time from the perspective of its two purposes mentioned in class. Then you can establish a reasonable detector design, setback, and phase passage time.

Tasks (1) DOWNLOAD the file named “LAB 1 DATA.xls” from the course design lab webpage. (2) CREATE a column labeled “DETECTOR ON-TIME”. (3) COPY the arrival time data into it. This arrival time is the time that vehicles arrive at the upstream edge of the detector. [detector status (objective 1)] (4) CREATE a column labeled “DETECTOR OFF-TIME”. (5) CALCULATE the DETECTOR OFF-TIME using the data in the “DETECTOR ON-TIME” column, a vehicle length of 18 ft, a detector length of 20 ft, and an average approach speed of 22 mph. [detector status (objective 1)] (6) CREATE a column labeled “DETECTOR GAPS”. (7) CALCULATE the detector gaps by finding the difference between the current detector on-time and the previous detector off-time. [gaps a controller sees (objective 2)] (8) DETERMINE the response of the controller for three different passage time settings (2.5, 3, and 3.5 seconds) using the results of task 7. Show the response by the percentage of gaps resulting in an extension of the phase or a gap-out termination of the phase. [controller response (objective 3)] (9) EVALUATE the effectiveness of a 50 ft detector setback, given an 18 ft vehicle length and 22 mph approach speed. Give specific consideration to the two purposes of passage time. (10) DESIGN a more appropriate detector setback, considering the passage time’s dual purpose and using ta an 18 ft vehicle length and a 22 mph approach speed.

Deliverable Electronically submit your spreadsheet and a report. You must clearly organize and label the spreadsheet as specified in the above tasks. Discuss the results of tasks 8, 9 and 10 in your report. Give special attention to the following:  Describe and explain trends in the percentages you found in task 8.  Describe why the detector setback in task 9 is, or is not, effective  Justify the statement that your design in task 10 is more appropriate then that used in task 9. Your work will be graded based on neatness, completeness, accuracy, and quality of thought (25% for each).