ARLINGTON, Va. – After nearly a decade of battling unions over its hours-of-service rules, the U.S. government appears to have picked a new fight—this time with carrier companies.

In an attempt to justify its proposed changed to the federal hours of service rules for drivers, the American Trucking Association claims that the DOT’s Federal Motor Carrier Safety Administration (FMCSA) is overstating driver fatigue as a main cause of truck crashes.

The ATA says the agency is now inflating its own crash numbers so as to elevate the risk of fatigue.

"Without this, and several other ill-considered revised assumptions, the proposed rule would fail the statutorily required cost/benefit analysis," ATA states in a press release.

“Since the current HOS rules were introduced in 2003, the trucking industry has achieved a continually improving safety record, reaching the lowest fatality and injury rate levels in recorded history," said ATA President Bill Graves "It is troubling that this complex, restrictive set of proposed rules is founded on what appears to be incorrect analysis and inflated math."

In the HOS proposal’s Regulatory Impact Analysis (RIA, the cost/benefit justification), FMCSA inflated its estimation of the percentage of fatigue-related crashes in two ways, explains ATA.

First, it overstated the percentage of single-vehicle truck crashes (which are more likely to be fatigue-related) compared to multi-vehicle crashes. In fact, ATA says FMCSA doubled the weight given to single-vehicle truck crashes in its large truck crash causation study.

Also, FMCSA appears to be treating any crash in which fatigue is listed as an ‘associated factor’ as a fatigue-caused crash.

"That approach is not just contrary to prior research methods, it is also at odds with the agency’s own report to Congress, in which it stated that for associated factors: "No judgment is made as to whether any factor is related to the particular crash, just whether it was present.”

Other "associated factors" the agency cited are emotion/experience, traffic, vehicle, roadway, weather and speed/distance – "each of which has a higher prevalence as a factor than does ‘fatigue’ but which, similarly, should not be read as a principal cause” of a crash," FMCSA stated.

Consistently in past rulemakings, adds ATA, the agency has found fatigue to be a causal factor in just 7 percent of crashes.

In fact, the Fatality Analysis Reporting System – a resource the FMCSA has widely cited in the past — attributes only 1.4 percent of fatal truck-involved crashes to being "drowsy, asleep or fatigued" in 2009 – the seventh leading factor in large truck fatalities.

"Now, apparently to assist it in reaching a desired result the agency has ignored the real world data and its past pronouncements and adopted a 13 percent fatigue factor," says ATA.

Plus, the FMCSA has engaged in "creative accounting in other areas of the new proposed HOS rules to try and justify its position," adds ATA, including lowering its previously projected costs to the industry by as much as 50 percent and overstating assumed health benefits that AA says are "immeasurable and likely insignificant."

Curiously, while FMCSA appears to purposefully be focusing on single vehicle crashes to highlight fatigue, its own comprehensive analysis on truck crashes over the last decade indicates that single vehicle crashes specifically dropped a whopping 33 percent between 2007-2009 – all while the current HOS rules have been in place.