This is one of those posts with an actual disclaimer that "I am not an expert but..."

It's my understanding that tire companies self-certify DOT compliance - a big part of which is that they follow sizing and labeling conventions.

There is no such thing - again, to my knowledge - of a DOT physical testing approval "process," actually applied by DOT, with benchmarks against which tires must match.

This is also NOT the first - or 2nd or 3rd - time that a newly-introduced tire has had problems on the race track. The first instance that I saw was in the mid-'80s when IMSA's Renault Cup went from an S-rated Goodyear Eagle (175/70-13, point of historical interest) to the H-rated version. The new ones overheated and chunked, even when shaved to 2/32nds.

K