Ultra Start 15xx Manual de usuario descargar pdf (Pagina 35)

3-3

the regular movement keys. If a movement key is pressed, the count is reg-

istered in the “primary” movements (1-16). If the BANK1 key is held down

while a movement key is pressed, the count is registered in the “secondary”

movements (17-32). If the BANK2 key is held down while a movement

key is pressed, the count is registered in the “tertiary” movements (33-48).

Normally, the turning movements of less common events are counted with

the secondary and tertiary (BANK1 and BANK2) keys.

The secondary and tertiary keys are often assigned to truck movements.

For example, if a car makes a right turn from the north approach, then you

press button #2. If a light truck makes the same movement, you press and

hold down the BANK 1 key while pressing button #2, which is counted

in the secondary movements. If a heavy truck makes the same movement,

you press and hold down the BANK 2 key while pressing button #2, which

is counted in the tertiary movements. Since it takes a little more work to

press the BANK 1 and BANK 2 keys, the less common truck volumes are

assigned to the secondary movements.

When this data is processed using the PETRAPro software, you can get

percentage breakdowns of the data based on the different groups.

This is just one example of how the Bank keys can be used. They can also be

used for counting additional approaches if you have more than the standard

four at an intersection.

Preparing to do a Turning Movement Study

Before you start a standard turning movement study, you must ask

yourself the following questions.

• What are the user deﬁned buttons (1,5,9,13) going to be used for,

if at all?

• Are the Bank 1 and Bank 2 keys going to be used?

• Can one person do the study, or will it require two or more, using

separate TDC Ultras?

• How is the TDC Ultra going to be oriented?

The answer to these questions depends on the experience of the people doing

the studies; there are no simple rules of thumb we can give you to help you

decide. The important thing is to use your knowledge of the people doing

the data collection, along with your experience with the trafﬁc they are likely

to see in the ﬁeld, to decide in advance what the best strategy would be.

Chapter 3 — Standard Turning Movement Studies

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Ultra Start 15xx Manual de usuario Pagina 35