The Basic Steps in Building and Reading a Queuing Diagram
CE221 – Fundamentals of Transportation Engineering
A queuing diagram can be viewed as a plot of cumulative arrivals and cumulative departures
over time.
The horizontalaxis is time (minutes).
The verticalaxis is total vehicles (a count).
For each point in time, there are two vehicle totals (two counts)
One is a total count of vehicles that have arrived to be serviced.
One is a total count of vehicles that have been serviced and have departed.
Choose some time to begin counting; where total arrivals = 0 and total departures = 0.
Divide the study period into a series of time intervals.
For each interval, determine the number of vehicles that arrived in that interval and
determine the number of vehicles that departed in that interval.
Keep a running total of cumulative arrivals and cumulative departures.
When cumulative
departures = cumulative arrivals, every vehicle that arrived to be serviced has been serviced
and there is no queue.
At the end of each time interval; plot a point representing cumulative arrivals and plot a point
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Winter '04
 staff
 Transportation Engineering, cumulative departures, cumulative arrivals

Click to edit the document details