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How to understand the use of "no data" values in Paramics Analyser

UPDATED: August 11, 2017


Paramics Analyser versions before  6.7, did not interpret a null value as "zero" and is never used as an operand to the various statistical functions. This is because for some particular value type, a zero value can have a different meaning from null.
 
In Analyser, when presented with a "no data" value as an operand to either a comparison (e.g. sum) or multi (e.g. average) statistics, an error and the result of applying such a function will be returned as "no data".
 
A null value under queue statistics means that there was no queue on a lane. Queue data is only recorded when vehicle speed is less than queuing speed, as defined under: 

- User Manual -> Modeller -> Core Model Attributes -> Configuration -> Core
 
Example:
A model is simulated for 5 different runs. For the purpose of this example,we are wanting to analyse Link 1:2 which has a single lane. The queues for the simulated runs are recorded as:
 
Run 001 - null
Run 002 - 5
Run 003 - 8
Run 004 - 13
Run 005 - 6
 
The average maximum queue length for Link 1:2 is calculated as:
(5+8+13+6)/4 = 8pcus
 
Paramics Version 6.7 introduces the option to allow users to specify whether null is interpreted as zero or be ignored altogether.
 
With the user specifying for null to be calculated as a zero value, the new average maximum queue length for Link 1:2 will be:
(5+8+13+6)/5 = 6pcus 
 
Users should be clear and understand how this impacts overall queuing results and contact customer support if further assistance is required.

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