The rolling test comes up randomly and then she has an specific amount of time to be able to pull over and take the test. It is written in paperwork, she should have been told by the installer, manuals, etc….
The amount of time when I had the smart start was 6 mins. That was plenty of time to be able to pull over if I needed to and a couple times I had to.
Nobody wants to get into trouble again when they have an interlock but you really do have to arm yourself with as much information as possible about your device and your specific state’s laws. You will feel much more comfortable afterwards.