The objectives of this lab are:
We will be counting vehicles and train compositions
at the intersection of the Union Pacific line and
For each hour time slot, one person should observe
northbound traffic and one should observe southbound traffic. The northbound
observer should be on the north side of the tracks along
Each person should select an arbitrary point along
As vehicles pass this point, record the times they do so to the second (as illustrated in the sample below).
When a train comes, record the time at which the train inhibits traffic (i.e., when the crossing signals activate) and begin to count the types of cars by classification. When the train passes (i.e., when the crossing signals stop and traffic begins to move again), record this time as well and begin to record vehicle times once again. (This is shown in the sample below).
After downloading the Excel file (i.e., diagram.xls), open it and note at the bottom that there are two Excel Worksheets available: Queueing Diagram and Alternative. The difference between these is the method of inputting the data and the resulting queueing diagrams.
For either worksheet, you must indicate the times for which you collected data and the direction of travel you were gathering data for.
For the Queueing Diagram worksheet, simply enter the time (in seconds) from the beginning of your data collection period (e.g., ) when each car passed the arbitrarily chosen point into the "Time (sec.)" column. Once done with that, copy the second entry of the Cum # Vehicles column from that point until the end of your vehicle times. This column should then have numbers increasing from 1 to the total number of vehicles passing during your data collection period. Then, change the graph's Source Data to reflect the size of your data entry fields (Click with the right mouse button when the mouse pointer is over the graph, select Source Data, and enter the appropriate Excel field sizes.) This method results in a discrete-looking graph.
For the Alternative worksheet, enter a one under the "Vehicles" column at each time (in seconds) from the beginning of your data collection period (e.g., ) when each car passed the arbitrarily chosen point. You may have to lengthen the "Time (sec.)" column to accommodate your data. Do this by choosing the last entry in the "Time (sec.)" column, copying it, and pasting it to the length of time required. Once the "Vehicles" column has all of its data, copy the last entry in the "Cum # Vehicles" column as you did for the "Time (sec.)" column. Then, adjust the graph's source data as mentioned for the Queueing Diagram worksheet. This method results in a more continuous-looking graph.
Assigned Times for data collection.
Vehicle counting sheet:
This sheet has space for 296 vehicles; therefore, if you use this sheet you might print multiple copies. Click here to view sample on a page by itself which facilitates printing.
The first vehicle on this data sheet passed at , the next at , the next at , and so on. You must only indicate the hour and minutes once per minute (or just the minutes once if you specify the hour on your data sheet somewhere). A train inhibited traffic at until, roughly, (the precise end time is shown on the train counting sheet).
Train counting sheet:
Click here to view sample on a page by itself which facilitates printing.
The first train on this sheet began inhibiting traffic at and stopped doing so at . There were 3 locomotives (as shown by the tick marks), 10 box cars, and so on. You may extend each train's data collection to additional rows if the number of cars warrant. You may also use the standard 4 marks and a slash notation to denote 5 cars.