ATRI report identified quottechnical issuesquot of the FMCSA restart study related to research design flaws and the validity of measurement techniques and interpretations as well as with data conflicts

Report slams FMCSA’s HOS restart field study for extensive research flaws

April 23, 2014
ATRI report pokes holes in validity of FMCSA's real-world review of restart provisions

The American Transportation Research Institute (ATRI) has released what it terms an “independent evaluation” that comes down hard on the scientific validity of the Federal Motor Carrier Safety Administration’s (FMCSA’s) recent “field study report” of the current Hours-of-Service (HOS) rules.  ATRI is the not-for-profit research arm of the American Trucking Assns. (ATA), trucking’s largest lobby.

ATA spokesperson Sean McNally told FleetOwner that the association had no direct comment on ATRI’s findings, but feels the new report “stands on its own.”

Per the authors of the ATRI report, “researchers reviewed the FMCSA 2014 field study report and identified a variety of technical issues related to the following: 1) research design flaws; 2) validity of measurement techniques and interpretations; and 3) data conflicts within and across the study.”

FMCSA had been directed by Congress via the MAP-21 highway bill to study the effectiveness of the restart provisions that were part of the revised HOS rule that went into effect on July 1 of last year.

Results were released in January of FMCSA’s study of the efficacy of the restart provisions of the revised HOS rule.

FMCSA said its study found that truck drivers beginning their work week with just one nighttime rest period under the “old” 34-hour restart of cumulative on-duty hours were less attentive, sleepier and more prone to lane drifting than drivers who began with two nighttime periods of rest-- as is required by the revised restart.

Per the agency, it conducted a “naturalistic field study” of 106 drivers (100 men, 6 women) age 24-69 to assess fatigue in drivers working their normal schedules and performing their normal duties. The drivers were studied during two duty cycles and during their intervening restart breaks.

“Researchers performed a comparison of driver fatigue between duty cycles preceded by a restart break with only one nighttime period vs. duty cycles preceded by a restart break with two or more nighttime periods,” said FMCSA.

FMCSA stated that its study’s results “indicate that having at least two nighttime periods from 1 am until 5 am in the restart break helps to mitigate fatigue.

“These results are consistent with earlier, laboratory-based studies of the restart break, and constitute further evidence in support of the efficacy of the new restart rule,” the agency added.

According to ATRI, its researchers documented no fewer than eight crucial issues with the findings of FMCSA’s report:

  • The field study report purports to have measured differences between restarts with one and two nighttime periods (1 am to 5 am) but instead measured differences in restarts that range from 34 hours to an unknown/non-limited number of hours off-duty
  • MAP-21 required that the field study be “representative of the drivers and motor carriers regulated by the hours of service regulations” but the study includes, on average, less than 12 days’ worth of data for each of only 106 drivers.
  • The FMCSA field study does not present research to support the limitation of the use of the 34-hour restart to once per week (168 hours).
  • Use of the 3-minute Psychomotor Vigilance Test (PVT) showed lapses of attention by drivers in both duty cycle groups, but offered no link between the average number of lapses, fatigue and the safe operation of commercial vehicles.
  • The two duty cycle groups had lane-deviation measurements that differed by 1/10th of a centimeter and the study authors provide no evidence that these findings are relevant or have a nexus to driver fatigue in either of the two groups
  • The difference in sleep obtained by the two duty cycle groups on their restart breaks differed by only six minutes per 24-hour period
  • Average driver scores on the subjective sleepiness scale did not indicate any level of sleepiness
  • The study confirms that drivers in the “two or more nighttime” group are more likely to drive during the day; a time when FMCSA’s own data shows a higher crash risk

“The ATRI assessment also identified critical information not detailed in the field study report which would have provided greater clarity on the study methodology and how the findings relate to the impact of the new restart provisions on commercial driver fatigue,” the report’s authors noted.

“FMCSA has heard loud and clear from carriers and drivers that the new rules are not advancing safety and are creating additional stress and fatigue on the part of truck drivers,” Steve Rush, president of Wharton, NJ-based Carbon Express, Inc. commented in a statement released by ATRI.  

“ATRI’s analysis raises enough questions about FMCSA’s own study that [it] should compel a comprehensive review of the entire rule,” Rush added.

The highly detailed 19-pg ATRI report was authored by ATRI’s president & COO Rebecca Brewster and senior research associate Jeffrey Short.

A copy of the report is available via the ATRI website:

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