What causes the triangle lap time notification?

Question

In Forza 3, there's an icon I colloquially call the "slop" icon. It looks something like this:

I've figured out a few of the conditions for it, but a few more elude me. This definitely seems to happen whenever you collide with any other car, the walls, an obstacle, etc. (Including just a quick rub.)

But other times ... I swear I've seen it come up when I've had no contact with anything and have stayed on the track. I've seen laps start with it when the previous lap had it.

What are the conditions for this notification? It's not really detailed in the manual.

Answer 1

From the Forza forums:

Certification guide:

Forza 3 contains two different types of lap times. Certified and uncertified. Certified times are always ranked higher than uncertified times, no matter how fast they are.

To uncertify your times, there are a few things that could happen:

Go off track
Hit a wall
Hit another car
Draft in front or behind another car at over 100mph
Rewind

One other thing that can uncertify your times is doing something to uncertify in the last sector of a lap. This will uncertify the next lap as well.

There is one source of confusion, and that is whether bottoming out uncertifies your lap or not. In my experience, it does not. Bear in mind, on Le Mans, it is very easy to uncertify by driving outside the white lines, even though you are still on the tarmac. This is not a glitch, so try to be careful.

Drift Certification

There are two things that will uncertify a Drift lap:

Going backwards
Using rewind

This lines up with what I remember about the game, although I've not played in a while.