Our gaming group plays and we only recently got beyond guessing the rules to aligning with the more official guidelines. I went over our driving sesssion in a video here https://www.youtube.com/watch?v=YS3GpX9_P6c

At around 4:05 there is a particularly tight situation where I wasn't sure how the rules apply. In particular you can make one block but if you make it near a corner when somebody is almost by your side but not quite it gets fuzzy when the responsibilities shift. If you are by the side they can't squeese you out of the road but if they manage to get in front you can't ram them.

What determines if there is "overlap"? For fast speeds that there is an inch of overlap a micro second before the contact seems insufficient but for slow relative speeds it seems counterintuitive that a car could move sideways and the behind driver have to artificially brake (or is it legitimately how that plays out?).

So how one disintinguishes a barge pass from a forbidden squeezing?

I assume you are using LFS rules of clean racing as a base.
Substantial overlap usually [f1metrics] refers to having your front axle atleast in-line or further than their rear axle.
And the point when you check this is the turn-in point.

Purple car didn't have substantial overlap before turn-in point, so any contact is his fault.

Quote from Shalkka :

So how one disintinguishes a barge pass from a forbidden squeezing?

Barge pass as in the video. Forbidden squeezing when there is enough overlap before turn-in point, and therefore both cars are entitled for at least car widths space throughout the corner.

Yes, that is what I am basing the observations on.

On the fly there only being a lot of subjective viewpoitn and attention levels can make it pretty shaky to eventually solidify.

So it seems it is pretty on track.

Now there are 2 more analysis videos. Among the drivers there was disagreement on when the turning happens for the purposes of barge passing. The additional materials are ambigoius in that there is a whole phase "turn-in" and a subpoint of the phase where that is also called "turn-in". One stance says that when you start breaking for the corner that is when the straight ends. Another holds that when the car starts rotating that is when the turn starts.

In partiucalr it seems pretty hairy if a person behind has more speed when a turn is coming up. It is very sensitive on when the oblications to avoid startm as there is no natural other reason to be careful.

Quote from Shalkka :

At around 4:05 there is a particularly tight situation where I wasn't sure how the rules apply. In particular you can make one block but if you make it near a corner when somebody is almost by your side but not quite it gets fuzzy when the responsibilities shift. If you are by the side they can't squeese you out of the road but if they manage to get in front you can't ram them.

So how one disintinguishes a barge pass from a forbidden squeezing?

Barge passing is when there is not big enough of a gap entering the corner but the behind car forces a gap by sticking his car inside anyway, bumping the opponent wide. Not to be confused with dive-bomb, which is a long distance out braking move into the corner that if misjudged (or if the car ahead does not see the divebomber), will result in contact.

Squeezing is when a car is substantially alongside (method of adjudicating right to racing room is front of car wing/bumper alongside the door B-pillar of the car ahead, or in the case of open wheelers, the ahead driver's helmet) denies one or the other a minimum 1-car width to the edge of the track. Certain situations, such as into quicker corners or when there is a big speed difference in favour of the car behind, this rule may be altered to "front tire of car behind, to be fully alongside rear tire of car ahead). This is where Stewarding hindsight comes in and also why most big events have a crib full of stewards to get a fair, unbiased view. Remember not all incidents are the same.

For the incident at 4:05, to my best ability I would call it a racing incident, with more blame to be put on the car behind. Why? The car behind (overtaker) has full responsibility of maneuvers, especially when there is no overlap and, in this case, attempting a dive-bomb from 1 car back. However, the front car defending made a move in the braking zone, which I've learnt the hard way, is now prohibited in (most) racing. So... takes two hands to clap, and volia the contact is made. Both are at fault, but since it's the job of the overtaker to not cause an accident, the "root cause" can be put on the car behind.

Still, a racing incident, as both did not display racing etiquette or good judgement.

I got far with the advice but as racing gets tighter the margins get smaller.

Got an even closer situation https://youtu.be/7cPWrCeRHNg?t=203 purple car thinks this is commendable "late braking" while I am thinking that I ended my straight and started my turn in front that I am good for protection. Is "turn point" per car or does the track have an objective spot where in space or time checks canbe made?

Is there some rule which differentiates divebombing out from forbidden barge passing? I was using a definition that the turn-in point is where the car starts breaking for the corner and this is checked for the car in front. If such a car has to in any shape or form move out of the way of anyone that at that moment behind its the forbidden type of move. A conflicting view was that turn-in happens when the cars orientation changes ie rotation happens.

Without going into specifique details:
I think it is not so important how excactly a situation is judged.
It justs needs to be consistent. Even simple things like "When is a car considered to be off the track?" are not easily answered. Some say all wheels must be on the track, others say two wheels are enough.
Sometimes the curbs are seen as part of the track, sometimes not.
It is similiar with overlap, turning in, defensive moves etc.

Almost any interpretation of the rules is okay.
But most important is that the rules are always interpretated the same. All situations should be judged by the same standard.

First collisions seem rather mundane incidents, but from 1/4 of the video, it looks more and more like Piran Moto Destruction Derby race, made me laugh thinking what would be if one would apply rules to those.