What is intersegment time for?

Hi people,
I am using inter-segments time, because I thought that it was a time to let the next drivers to be ready to race.
But, when the time of the inter-segments is finished, nothing happen, not a countdown, and if I push the restart, it starts right away, no countdown.

Beside that, when I configure intersegment time to 0, when I push restart, the countdown starts, lights included.

Can you help me to understand intersegment time?.
Thank you.
Eduardo.

I still need to know it.
Anybody can help me with this.
I removed from my race for this sunday, but would be great somebody help me to find out what is this for, or how should I use it.
Thank you.
Eduardo.