Leading Safety Expert Casts Further Doubt On Hours-of-Service Research

Concludes that the sample of drivers, trucks and crashes, as well as minimal attention paid to other factors in crashes, rendered a study of little value.

Arlington, VA: An internationally recognized safety researcher said the cache of studies submitted in an extraordinary manner by the Federal Motor Carrier Safety Administration to support its flawed hours-of-service proposal contained many problems and couldn't be relied on to support the agency's proposed changes.

Dr. Ronald R. Knipling, the former head of FMCSA's research division and the first American to receive the prestigious Order of Merit from the International Road Transport Union for his work on truck safety, called into question the validity of the studies FMCSA inserted into the docket on May 6.

Knipling raised "fundamental criticisms" of a study conducted by researchers at Pennsylvania State University, concluding that the sample of drivers, trucks and crashes, as well as minimal attention paid to other factors in crashes, rendered the study of little value.

"It would be erroneous and unwarranted to accept Penn State's principal findings and conclusions without extensive re-analysis, internal validation, and external replication," he wrote.

Similarly, Knipling, said a study by the Virginia Tech Transportation Institute was lacking and concluded that "more probing and self challenging analyses must be performed before [the] study['s] findings can be accepted as sound science."

Regarding a study of Florida transit bus drivers, Knipling concluded that the "significant differences between Florida's transit bus operator work rules and those for interstate truck drivers render schedule-related research findings for one largely inapplicable to the other."

Knipling also submitted a summary of his own work on the subject, where he finds that fatigue related to lack of prior sleep, being awake for more than 16 hours and early morning driving was associated with many single vehicle truck crashes, while fatigue "related only to driving and work schedules (e.g., as prescribed by daily hours-of-service rules) were not. This non-association was confirmed by several different types of analyses."

In addition, Knipling noted that the risk of all types of truck crashes increased during daytime driving, "consistent with increased exposure."

"For a third time since FMCSA began this ill-advised revision of the hours-of-service rule, an expert in the field of truck safety has called into question the science FMCSA is using to advance these unwarranted changes," ATA President and CEO Bill Graves said. "Dr. Knipling's recent work in reviewing the latest reports only underscores how weak FMCSA's case for change really is."

"We have said from the beginning that changes to the rule must be made based on sound science and hard evidence, not political motivations," Graves said. "The facts couldn't be more clear: since the current rule went into effect, while driving more miles trucks have been involved in far fewer crashes and no amount of misapplied research can refute that fact. FMCSA should abandon its ill-advised proposal and turn its focus to improving enforcement of the current, effective hours-of-service rule."