Units for turning counts and traffic flows

I have entered turning counts for each 15-minute time segment but the results look far too high/low. What am I doing wrong?

The answer to this and similar questions is that you should always check which units each screen uses. All relevant screens always show the current units at the top of the screen or next to each data item. You can customise the units at any time, but it’s important to note that this affects ALL relevant screens. To change units, select Data>Units from the main menu and then choose from the various options. The choice of units is saved with the file.

When you start a new file, all flows are in PCU/hr. Even if looking at an individual 15-minute time-segment, in the flows, results or turning counts screens, the flow is still in PCU/hr. For example, if 100 PCU are counted in 15 minutes, this is 400 PCU/hr. Using the same units in this way makes it easier to work with rates in a consistent way. If you prefer to enter actual counts per time-segment, simply change the Traffic Flows option in the Units screen to ‘per time segment’. (You can change back and forth as many times as you like, and any previously input data will automatically be displayed in the new units.)

I have entered turning counts/flows using the wrong units. When I change units, the values in the screens change. How can I change the data into the correct units?

As an example, say you have a count of 100 PCU in a 15-minute time segment, and enter this directly as 100, not realising that ARCADY is in PCU/hr mode. ARCADY would interpret the value as 100 PCU/hr, whereas you wanted 100 PCU per 15 minutes, or 400 PCU/hr.  If you have made this kind of mistake, then simply changing the units used, does not work, because Junctions automatically converts the existing data into the new units when you change units.  However, as an alternative to changing the units and re-entering all the data by hand, you can select Edit>’Copy/Paste all Demand Sets / Time segments’ from the main menu and select the option you need, in order to paste all the data you have onto the clipboard.  Simply change the units before going back to the ‘Copy/Paste all’ screen; select the ‘Paste’ option, and paste the OD data back into your file.

If you only need to change the data for one grid then you can simply click in one of the cells in the OD data grid; click ‘copy’ on the horizontal toolbar; change the units and click ‘paste’ to return your data to the grid.  Your data will now be in the correct units.

Alternatively, since you know that all the flows need to be made 4 times bigger, you could simply enter a flow scaling factor of 400% for each arm. (This is only possible if you’re not already using the flow scaling factor.)