Linda, when it comes to these stats, they seem to be an aggregate of all of the accident reports with some being assumptions, not facts. This is illustrated with the justification of the sleep apnea requirements we go through, the studies done on accidents don't include valid truck related accident data and when it is used and broken out, it is not correct data in context to the accident.
Same way they insist speed is a cause of [or contributor to] crashes without any justification except 'we say so'. If the driver of any vehicle involved was exceeding the posted limit [even if they're just guessing], speed is listed as a contributing factor.
It works for their purposes - more money budgeted for LEOs to catch the dangerous speeders and insurance companies increase rates for speeding tickets, courts and the cities benefit from the fines - but not a bit of it is based on solid proof.
DOT and FMCSA are following the same pattern: allege a safety hazard often enough, it is accepted as fact, and then they can perpetuate their own jobs by creating programs to counter the threat.
It would be great if they had to prove their contentions, but apparently, they don't.