HOS 8-2 sleeper rule called good for day drivers, bad night owls

By LYNDON FINNEY
The Trucker Staff

5/25/2008

SPOKANE, Wash. — The current Hours of Service sleeper berth rule is fine if you drive during the day and sleep at night, but it is unequivocally not good if you drive at night and sleep during the day.

That’s the opinion of Dr. Greg Belenky, research professor and director of the Sleep and Performance Research Center at Washington State University, Spokane.

Belenky co-authored a report titled “Split Sleeper Berth Use and Driver Performance: A Review of Literature and Application of a Mathematical Model Predicting Performance from Sleep/Wake History and Circadian Phase,” prepared for the American Trucking Associations and submitted by ATA to the Federal Motor Carrier Safety Administration in response to the comment period for the Interim Final Rule on Hours of Service.

“The model takes what is known about sleep and performance and encapsulates it — especially the relationship between sleep and performance and what we call sleep/wake history, which is how much you’ve slept and when over the last few days,” Belenky said in an interview with The Trucker.

“The 8-2 split [sleeper berth rule] is fine provided you’re driving during the day and sleeping at night, but our model predictions showed that if you drive during night and sleep during the day, it is terrible because you really won’t get adequate sleep,” Belenky said. “If you had to have a one-size-fits-all schedule — a rule which we don’t think is the right idea — then it would be five and five. In other words, if you are driving at night, you would like to get some sleep during the night, at least two, three or four hours. In other words, the ideal thing would be not to drive the whole way through the night, but to be able to take a nap of some sort here and there.”

Belenky said during the study, researchers looked at several regimens.

“Eight and two was terrific if you were working during the day and sleeping at night and five and five probably produced the best overall performance if you didn’t know when you were going to be sleeping or when you were going to be working. We also looked at 5-4-1, 6-3-1, 8-1-1, things like that. They all sustained reasonable levels of performance, but the best was 8-2 if you’re going to be sleeping during the night, but 5-5 gave the most even performance if you were sleeping around the clock. If you’re long haul, 5-5 or 6-4 would probably be best. The research argues for letting the driver manage his or her own affairs within the broader prescriptive shell of 14 on, 10 off, but they ought to be able to divide the 10 off as they saw fit. Ten hours off if you are using a sleeper berth is a nice generous offer for time off, and people ought to be able, if they time things right, to be able to get a decent amount of sleep under those circumstances.”

The so-called 8-2 sleeper berth rule was issued in 2005 after a federal court struck down the Hours of Service rules issued in 2003.

One of the reasons cited for overturning the rule was the court’s finding that FMCSA had not taken into account how the rules impacted the health of drivers.

The 2003 sleeper berth rule said that drivers using a sleeper berth had to take 10 hours off duty, but could split sleeper berth time into two periods provided neither was less than two hours.

The 2005 rule said that drivers using the sleeper berth provision had to take at least eight consecutive hours in the sleeper berth, plus two consecutive hours either in the sleeper berth, off duty, or any combination of the two.

For the most part, motor carriers, associations representing drivers and drivers themselves didn’t like the 8-2 rule because they said it removed flexibility from setting sleep schedules that allowed truckers to drive when they were alert and sleep when they were sleepy.

The court also overturned the 2005 rule, primarily for procedural errors, and late last year, the FMCSA issued the Interim Final Rule, which retained the 8-2 split.

“We are committed to putting into place an HOS regime that improves highway safety by ensuring that drivers have adequate opportunities for rest at the end of each work day and during the work week,” FMCSA administrator John Hill told The Trucker. “The Interim Final Rule for HOS is based on real data that shows it will work to reduce the risk of driver fatigue while improving road safety.

“Safety continues to be the central factor as we go through the HOS rulemaking process. While I cannot comment on the final rule’s disposition, we intend to complete it by the end of the year.”

 There are two big issues determining how someone performs, Belenky said.

“One is how much sleep you’ve been getting and how long you’ve been awake and the other is the time of day, or the circadian rhythm,” he said. “There is a normal circadian rhythm and body temperature with body temperature rising about two degrees in the evening and falling two degrees to the wee hours of the morning. One of the reasons you feel so lousy about 4 in the morning is because your body temperature is low and your performance is down.

“There is a rhythm in alertness that follows the circadian rhythm. Your alertness actually rises over the course of the day counteracting the fall of performance that is a function of time awake. Your performance and alertness actually peak around 10 p.m. So there is the circadian rhythm and performance peaking about 10 in the evening and reaching its minimum at 6 or 8 o’clock in the morning.”

The mathematical model is a two-process model, Belenky said.

“One is degradation in performance relatively linear over time for time awake and the other is a cyclic function of time of day,” he said. “What the combination of working during the day and sleeping at night does is this: as your performance deteriorates over the course of the day, the circadian rhythm boosts you from below and gives you about 16 hours of steady performance. Around 10 p.m., not only have you been awake a long time, but the circadian rhythm goes south, and so you have these combined effects. The circadian rhythm really serves to consolidate sleep during the nighttime period.”

Sleep is least likely in the early to mid-evening hours and most likely in the wee hours of the morning, Belenky said.

In the report submitted to FMCSA, the co-authors said that in 2003 and 2005 when the current rules were written, there were limited studies bearing on the issue of the recuperative value of split sleep.

Now, there are some studies suggesting that if total sleep time is the same it doesn’t really matter if you consolidate or split your sleep, that split or consolidated sleep are just as recuperative providing you don’t split them too much, Belenky said.

“If you’re waking every two or three minutes, that’s different,” he said. “If you got a main sleep of six hours and a nap sleep some other time of the day of two hours and it overall summed to eight hours over a 24-hour period, that’s the equivalent of sleeping eight hours straight. And you could probably get away with one more division. You could probably divide your sleep in three. There’s a certain cost to dividing your sleep because it takes you some time to fall asleep each time. So that’s sort of lost. Jim Fitzpatrick, who was a co-author on the report said: “drive when awake, sleep when sleepy.”

When someone works nights, they are working through their low body temperature.

“So your performance, even if you’re well rested, is going to be impaired for that reason because the circadian rhythm dips in the early morning hours,” Belenky said. “The circadian rhythm determines when there is a sleep-conducive time of day and when it’s almost impossible to sleep. So you’re much more able to fall sleep when you body temperature is falling or low.”

The magic hour is around 10 p.m., he said. That’s when the body temperature starts to fall and it becomes very easy to fall asleep.

“Conversely, your performance is not good,” he said. “When your body temperature is high or rising, it’s hard to fall asleep and your performance is good. So if someone is working at night, they are working through their circadian low and their performance is impaired. Let’s say they try to go asleep at 8 a.m. Initially, since their sleep drive is high because they’ve been up all night, they’ll sleep. But gradually, their body temperature starts to rise and they pay off some of their sleep need, so typically at 1 in the afternoon they’ll awake after only five hours of sleep. And at that point, they are unable to go back to sleep, unless later in the afternoon they can grab an hour or so. So people who work the night shift, whether it’s trucking, nursing, other medical professions, police, commercial aviation, what have you, people who work the night shift are trying to work through this low period and trying to sleep at the wrong time of day.”

(See Eye on Trucking on Page 30 for information on studies about healthcare workers and performance).

Regardless of how long a person has been working nights, their circadian rhythm never changes, Belenky said.

“So the nighttime worker never really re-synchronizes to the schedule so they are perpetually jetlagged is the way to look at it,” Belenky said.