TR9302-CS 930525To: Rey Gonzales, Street Superintendent
From: Kenneth M. Griffin P.E., City Engineer ~
RE: Traffic Light Synchronization Grant "After Study"
Date: May 25, 1993
I have reviewed the "After Study" provided by Barton-Aschman for the TLS II Program. The
numbers allocated to the yearly savings for this project seem staggering. I find it hard to believe
that the synchronization of six lights will contribute to an approximately $2,000,000 a year
savings. In considering this savings, do you know if they considered the increased time for
vehicles exiting side streets.
On Table 3, entitled "Summary of Improvements Before verses After Conditions", I am a little
concerned about the off/noon comparison for the stops. The number of stops and the total
system delay for that time period was increased yet on the last column they show a decrease in
the amount of fuel consumption. Those three columns don't seem to coordinate and it appears
they should be reevaluated.
On Table C, entitled "Transyt-7F Calibration Summary", I have a question about the prediction
by the computer. In the before study, the computer predicts a certain time it would take to
travel Denton Tap Road. Then the signals were synchronized and improvements made. In the
~After Study~, the computer makes another prediction on the amount of time it takes to travel
Denton Tap and it predicts it is going to take longer to travel Denton Tap with the improvements
in place. Why would the computer predict it would take longer after the improvements? There
seems to be a glitch or error in the computer setup.
The following are minor spelling errors: 1) on page 3, the words "Coppell" and "Lake" need
to be capitalized; 2) on page 11, on the last line, the word "Lengths" is misspelled.
These are the only comments offered by the Engineering Department. Basically, I am concerned
with Table 3 and Table C on some of the data presented and I am also concerned with the
perception that we are saving close to $2,000,000 based on the improvements. Again, I find
that number staggering and hard to believe.
If I can provide any information about the TLS II Program please feel free to contact me at your
convenience.
file/kgriffin/tr9301.sdy