User`s manual

TDC Ultra User’s Manual
8-4
Saturation Flow Rate Template
Page 7-2 shows the template that is used for Saturation Flow Rate studies. It
is color coded to make the study easier to perform. The Signal Phase keys at
the bottom of the template show the proper colors. The keys labeled 1C-4C
are primarily used during the green phase of the signal, therefore they are
surrounded by a green border. The keys labeled 1S-4S are used only during
the red phase, so they are surrounded by a red border.
The keys labeled 1C-4C represent individual lanes on the approach to
the intersection under investigation. In theory you can monitor up to four
lanes at once. In practice it is rarely necessary to do more than two lanes.
You are primarily interested in the worst case situation, and that is usually
limited to one or two lanes. You need to assign a given key to a given lane.
You can use any of the four keys for any of the lanes, however it is easier
to remember which key corresponds to which lane if you choose keys that
match the lane configuration on the street.
If you are measuring the two through lanes, then use 2C and 3C. If you
are measuring the left turn lane, then use 1C. Select keys that match the
geometry.
Each of the keys 1C-4C has a corresponding key labeled 1S-4S. They have
the same color and arrangement. It is important that you use the proper pair
of keys while you do the study; if you use 2C then you must also use 2S.
At the top of the template is a very important key, the OOPS! key. This key
deletes the last keys that were pressed. If you hit the wrong key (especially
one of the phase keys), then you can quickly press the OOPS! key and
then the correct key. If you hit several wrong keys in a row then you can
repeatedly press the OOPS! key to try to get back in sync. Each press of
the OOPS! key removes one key.
The OOPS! key is especially valuable if you hit a phase key by mistake.
The analysis of the data for that cycle will be wrong if the phase timing is
wrong. An error in the 1C-4C or 1S-4S keys is not as damaging, although
errors should be corrected as quickly as possible.