Feature/ab#1981 add flow type

[witchpou]

Description

Added occupancy for traffic flow analysis.

Motivation and Context

How has this been tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[flonix8]

I found two nitpicks, but aside from that I'm fine with the changes. Thank you for improving the structure!