FMCSA study examines driver sleep patterns

by Fred Nix

WASHINGTON, D.C. -Team drivers and sleeper berths may not be as bad for fatigue as some people think.

That, at least, is the conclusion of a new report from the Federal Motor Carrier Safety Administration (FMCSA) in the United States.

The FMCSA study, while confirming that sleep in a sleeper berth is not as good as sleep in a bed (your own or a motel’s), shows something surprising.

Team drivers are far better drivers than single drivers on long trips.

According to the study report, “…team drivers were generally very successful at avoiding circumstances of extreme drowsiness. Conversely, single drivers were greatly affected by drowsiness, which in turn, compromised their ability to safely operate their vehicles.”

The FMCSA has been working on this study of sleeper berths for several years as part of the effort in both Canada and the United States to revise the hours-of-service regulations for truck drivers. The actual contractors for the FMCSA were the Virginia Tech Transportation Institute, the Virginia Tech Department of Industrial and Systems Engineering, and the Harvard Medical School.

The concern with the current hours-of-service regulations is that they are too complex, open to abuse and are not solving the problem of tired drivers.

In fact, U.S. data suggests that fatigue is the cause of, or a contributor to collisions in 17 per cent of the truck-related collisions.

The FMCSA study documented the sleep and driving habits of 30 drivers driving single and 26 drivers driving in teams over a period of time.

These were regular drivers for several U.S.-based for-hire carriers who were recruited for the test by being given one of two specially equipped tractors with monitoring equipment, including four video cameras.

The equipment recorded things such as whether the tractor wandered over the white line on the road, hard braking, how rapidly the driver turned the wheel, the lateral (sideways) acceleration of the tractor; how many times a minute the driver blinked, how rapidly the tractor approached a vehicle in front of it, and other factors.

This information was used to define ‘critical events’- that is, incidences of bad driving.

Critical events were also graded by the researchers, in reviewing the videotapes, in terms of how severe they were.

Critical events caused by other drivers were not used in judging the driver’s performance.

The drivers were paid for participating in the test and, in fact, were also paid a special bonus for wearing fancy headgear when they were sleeping so that their movements could be monitored.

This headgear-nightcap sleep monitoring system-could tell how much REM sleep the drivers were getting.

“REM,” rapid-eye-movement, sleep is known to be the good-quality sleep needed to overcome fatigue.

It is from this information that the FMCSA researchers concluded that sleep in a sleeper berth isn’t as good as sleep in a bed.

The Harvard Medical School analyzed this REM-sleep data and, while the findings are believed to be sound, they admit there were problems in collecting the information for the team drivers using the sleeper berths. Presumably, the motion of the truck introduced a certain amount of “noise” in the data.

But while the quality of sleep the team drivers got in the sleeper berth may not have been as good as that of single drivers, this didn’t seem to affect the performance of the team drivers.

“From the data collected in this study, it was apparent that the team driving operation translates into fewer bouts of drowsiness, fewer critical incidents, and, in general, safer trucking operations,” according to the authors of the report.

Team drivers, on average, had 40.3 critical events while being monitored.

Single drivers had an average of 146 critical events, over three-and-a-half more than their team-driver confreres.

Possibly one factor accounting for this is that team drivers, while not getting the same quality of sleep as single drivers, average almost one hour more sleep a day while on the road than single drivers.

Current regulations in both Canada and the United States make an exception in the hours-of-service rules for drivers in trucks with sleeper berths.

For most drivers there is a mandatory eight-hour off duty period between working shifts.

But for drivers with sleeper berths, the rules allow the eight hours to be taken in two periods, as long as no off-duty period is shorter than two hours.

In the process to revise hours-of-service rules in both countries there have been suggestions that the exemption for hours off for drivers in trucks with sleeper berths should be eliminated.

The National Transportation Safety Board in the U.S., in particular, has argued that this exception is not a good regulation.

The reasoning is that drivers don’t get good quality sleep in a sleeper berth.

Indeed, this thought, is borne out by many drivers who complain that they can’t really recover from fatigue while in the sleeper.

Under the proposed new Canadian hours-of-service rules, agreed to by all provincial transport ministers last fall in Winnipeg, team drivers in trucks with sleeper berths will be allowed to continue the practice of splitting their off-duty time into two shifts.

But, instead of one of these shifts being a minimum of two hours (current rules), the minimum time off will be increased to four hours.

Single drivers will fall under the ordinary hours-of-service rules and have to take 10 hours off in every 24-hour period where one of the off-duty periods is at least eight hours long.


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