CE562 Traffic Engineering
Term Project: An Introduction to Timing Coordinated Signals
(Instructions for Preparing a 900E Arterial Model by Synchro 7)
Step 1.
In the Map window, create a 6-signal 900 E arterial from the University
Parkway intersection to Center St. intersection. External links should be 300
ft to 600 ft for simulation purpose (we use 1,000 ft). (See Page 3-2,
SimTraffic manual why this much length is needed. We do not conduct
simulation analysis in this class; we use SimTraffic to verify the correctness
of input data entry.) Link lengths are shown below:
 Between University Parkway and Birch Lane = 2,110 ft
 Between Birch Lane and 900 N = 1,580 ft
Note that the N-S is 900E and signals are coordinated in this direction.
Step 2.
For each of the three signals, choose the evening peak hour (See the attached
data sheets for the three intersections). Let’s consider 17:00-18:00 hr of the
day as the evening peak. Hourly volumes and PHFs are given in the attached
data sheets. We assume all approaches at an intersection have the same PHF.
Step 3.
Enter data in the Layout, Volume, Timing, and Phasing windows using the
information you find in the signal data sheets. Examine the timing sheets
carefully. Check which signals are pre-timed or actuated. If actuated, it will
become “actuated-coordinated” intersection. Click the Lock Timing button to
“simulate” the existing case by Synchro. Use SimTraffic to see whether input
data were entered correctly (especially the existence of detectors). Note that
coordinated through vehicles must have phases 2 and 6. In this case the northsouth direction gets phases 2 and 6.
Step 4.
After the correctness of input data entry is confirmed, get summary reports
from Synchro. Select MOEs you want to use. (Delays, number of stops, and
queue lengths are some of the MOEs interesting to use. Always think about
how you write a final report of this exercise. This file is called the existing
case.
Step 5.
After Step 4, make two copies of the existing case and name it “optimized
case” and “zero offset case.” Deselect the Lock Timing button and go to the
Time-Space diagram. Play with offsets to see how green bands, vehicle paths
(queue sizes) change. Find out manually the values of offsets that appear to
minimize the queue size at each intersection. (Note this is the most
important part of this 3-signal 900E arterial exercise. Which would be
better, increasing offset or decreasing offset? This exercise will prepare
you for Chapter 24.) Write down your observations to include in your report.
Getting a few screen shots will be of great help later on. Get a screen shot of
the existing case BEFORE you play with the offsets.
D:\106749421.doc
Step 6.
Then optimize cycle length, splits, and offsets of the optimized case file.
Write down the values of cycle length, splits, and offsets. Then, get a
summary of MOEs. Make sure you use the same MOEs you selected for
comparison in a previous step.
Step 7.
Run SimTraffic on the existing case, optimized case, and no-offset case. Do
you see visually any noticeable changes? Unfortunately SimTraffic does not
allow us to run two different cases simultaneously and see them side by side.
So you need to run it one by one. (You can see the two simulations side by
side if you can login two terminals. So, try this one.)
Step 8.
Compare the results of the existing case and the optimized case in terms of
the MOEs you selected, like LOS, intersection v/c, number of stops, queue
size, etc., using the outputs from Synchro. (Since this is not a simulation
class, you do not need the output from SimTraffic. We use SimTraffic just to
check if the inputs are correct and how the system is performing visually.)
Step 9.
Write a technical report discussing the background, description of the study
site, study methodology, results, discussions on results, conclusions and
recommendations, references, and appendices. The max number of pages of
the report will be 15 pages (double-spaced, letter size), including main body,
tables, figures, and references. Appendix may have as many pages as you
think necessary. Write a kind of report that you can use as a reference later
on.
You may summarize your work like a lab report. The following items must be
included in your lab report.
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D:\106749421.doc
Cover sheet
Purpose of the term project
A short description of the site
A summary statement on changes in MOE values & a table showing
MOEs of the existing case, optimized case, and no-offset case. MOEs
may include delays, the number of stops, LOS, queue lengths, etc.
State how much of improvement (in terms of delay reduction) would
be achieved by an optimized timing plan over the existing timing plan
and how worse it would be if no offsets are used.
A summary statement on changes in the time-space diagrams of the
existing case, optimized case, and no-offset case.