This is a very stupid question and I feel embarrassed asking it, but here goes.

When the tunnel says 80k, and you know it's timing you to get your average speed, but then when you're in the middle of the tunnel and it turns to 60.... What actually happens? Cause obviously you won't have an average speed of 60 by the time you exit.

And vice versa. I was going 60 today, then it changed to 80 and I went up to 80.

Do they do a grace period??? I've been driving for decades but have only recently had a job commute through the tunnel (south Auckland linking west). Had a speeding ticket going 84 while it was 80 once, but that was on a Sunday where it never changed, so fair enough. But the amount of times it's changed from 60 to 80 while I'm in the tunnel, or from 80 to 60, makes me wonder what actually happens with the average speed. Surely there's a grace period??!!

I live in Glen Eden. Working in Onehunga these days, I've never used this tunnel before this commute, but it seems to change speed while I'm right in the midst of it on the way home Monday to Friday