Asleep at the wheel - some
recent scientific papers
Authors
McCartt AT. Rohrbaugh JW. Hammer MC. Fuller SZ.
Institution
Institute for Traffic Safety Management and Research, University at Albany,
State University of New York, 12205-2604, USA. preusser@worldnet.att.net
Title
Factors associated with falling asleep at the wheel among long-distance truck
drivers.
Abstract
Data on the prevalence and hypothesized predictors of falling asleep while
driving were gathered through face-to-face interviews with 593 long-distance
truck drivers randomly selected at public and private rest areas and routine
roadside truck safety inspections. Hypothesized predictor variables related to
drivers' typical work and rest patterns, extent of daytime and night-time
drowsiness, symptoms of sleep disorder, measures of driving exposure, and
demographic characteristics. A sizeable proportion of long-distance truck
drivers reported falling asleep at the wheel of the truck: 47.1% of the survey
respondents had ever fallen asleep at the wheel of a truck, and 25.4% had fallen
asleep at the wheel in the past year. Factor analysis reduced the large set
of predictors to six underlying, independent factors: greater daytime
sleepiness; more arduous schedules, with more hours of work and fewer hours
off-duty; older, more experienced drivers; shorter, poorer sleep on road;
symptoms of sleep disorder; and greater tendency to night-time drowsy driving.
Based on multivariate logistic regression, all six factors were predictive of
self-reported falling asleep at the wheel. Falling asleep was also associated
with not having been alerted by driving over shoulder rumble strips. The results
suggest that countermeasures that limit drivers' work hours and enable drivers
to get adequate rest and that identify drivers with sleep disorders are
appropriate methods to reduce sleepiness-related driving by truck drivers.
Authors
Hakkanen J. Summala H.
Institution
Department of Psychology, University of Helsinki, Finland. hehakkanen@hotmail.com
Title
Sleepiness at work among commercial truck drivers.
Source
Sleep. 23(1):49-57, 2000 Feb 1.
Abstract
Two separate groups consisting of both long-haul (N=184) and short-haul (N=133)
truck drivers were surveyed to examine the frequency of driver
sleepiness-related problems at work during the previous three months and to
assess the incidence of sleep apnea syndrome symptoms. We also aimed to identify
factors likely to predict self-reported difficulties in staying alert in work
driving, dozing off (sometimes referred to as microsleeps) at the wheel and near
misses. The responses suggest that for approximately 13% of the long-haul
drivers the mean driving time per shift exceeded the EEC regulation. About
40% of the long-haul drivers and 21% of the short-haul drivers reported having
problems in staying alert on at least 20% of their drives. Over 20% of the
long-haul drivers also reported having dozed off at least twice while driving.
Near misses due to dozing off had occurred in 17% of these drivers. Factors
indicating sleep apnea syndrome occurred in only about 4% of the long-haul
drivers and in only two short-haul drivers. Work and individual related factors
as well as factors indicating sleep apnea syndrome contributed only slightly to
predicting driver sleepiness-related problems. This suggests that driver
sleepiness-related problems tend to be shared by many of the professional
drivers, rather than being a "specific" and permanent problem for a
smaller portion of drivers. However, difficulties in sleep patterns, such as
having difficulty falling asleep, were infrequent.
Authors
Pierce RJ.
Title
Driver sleepiness: occupational screening and the physician's role [editorial].
Source
Australian & New Zealand Journal of Medicine. 29(5):658-61, 1999 Oct.
Authors
Hakkanen H. Summala H. Partinen M. Tiihonen M. Silvo J.
Institution
Department of Psychology, University of Helsinki, Finland. hehakkanen@hotmail.com
Title
Blink duration as an indicator of driver sleepiness in professional bus drivers.
Source
Sleep. 22(6):798-802, 1999 Sep 15.
Abstract
This study focused on eyeblink duration as a measure of sleepiness in on-road
driving and on the driving performance of professional bus drivers with
polysomnographically confirmed mild obstructive Sleep Apnea Syndrome (OSAS). Ten
bus drivers with OSAS and their matched controls participated in the study. The
Maintenance of Wakefulness Test (MWT) and a monotonous on-road driving task were
completed. Eyeblink duration and frequency and speed control were measured while
driving. Lane-keeping was evaluated by the supervisor in the car. Subsequent to
these tasks, drivers with OSAS received continuous positive airway pressure
treatment (nasal CPAP). After nine weeks of treatment, the tasks were repeated.
Prior to treatment the average blink duration in the driving task was
significantly longer and sleep latency in the MWT was significantly shorter for
bus drivers with OSAS than for controls (mean blink duration 82.3 ms; 51.9 ms
and mean sleep latency 23.2 min; 35.4 min), indicating increased daytime
sleepiness. Subsequent to treatment both measures in drivers with OSAS decreased
to the level of the controls. Treatment effects in MWT and blink duration in
on-road driving also correlated significantly. No significant differences
between the groups appeared in average blink frequency or driving performance in
terms of maintenance of speed. No significant lane drifting appeared either.
These results support earlier findings on blink duration as an indicator of
increased sleepiness and have important implications for those involved in the
transport technological industry. The findings also suggest that nasal CPAP
treatment is effective in reducing excessive daytime sleepiness.
Authors
Barach P. David GB. Richter E.
Title
The sleep of long-haul truck drivers [letter; comment].
Comments Comment on: N Engl J Med 1997 Sep 11;337(11):755-61
Source
New England Journal of Medicine. 338(6):390; discussion 391, 1998 Feb 5.
Authors
Maycock G.
Institution
Transport Research Laboratory, Crowthorne, Berkshire, UK.
Title
Sleepiness and driving: the experience of heavy goods vehicle drivers in the UK.
Source
Journal of Sleep Research. 6(4):238-44, 1997 Dec.
Abstract
An interview survey of 996 heavy goods vehicle (HGV) drivers was undertaken. It
was designed to investigate the relationship between HGV drivers' accidents,
daytime sleepiness (measured using the Epworth Sleepiness Scale) and other
relevant physical characteristics. The drivers were sampled randomly at motorway
service areas. The average age was 41.4 y (SD 10.5), they drove an average of
69700 miles annually (SD 36120), and their average score on the Epworth daytime
sleepiness scale was 5.65 (SD 3.31). They reported an average accident liability
of 0.26 accidents in a 3-y recall period. Drivers who reported snoring
regularly whilst sleeping at night or who were obese or who had a noticeably
large collar size had higher accident liabilities than those not exhibiting
these characteristics. Accident liability increased with increasing scores
on the Epworth daytime sleepiness scale. These findings suggest that further
investigation of the mechanisms behind the higher accident rates of some
categories of HGV drivers would be justified in the interests of road safety.
Authors
Mitler MM. Miller JC. Lipsitz JJ. Walsh JK. Wylie CD.
Institution
Scripps Clinic and Research Foundation, La Jolla, Calif. 92037-1205, USA.
Title
The sleep of long-haul truck drivers [see comments].
Comments Comment in: N Engl J Med 1997 Sep 11;337(11):783-4, Comment in: N Engl
J Med 1998 Feb 5;338(6):389; discussion 391, Comment in: N Engl J Med 1998 Feb
5;338(6):389-90; discussion 391, Comment in: N Engl J Med 1998 Feb 5;338(6):390;
discussion 391
Source
New England Journal of Medicine. 337(11):755-61, 1997 Sep 11.
Abstract
BACKGROUND: Fatigue and sleep deprivation are important safety issues for
long-haul truck drivers. METHODS: We conducted round-the-clock
electrophysiologic and performance monitoring of four groups of 20 male truck
drivers who were carrying revenue-producing loads. We compared four driving
schedules, two in the United States (five 10-hour trips of day driving beginning
about the same time each day or of night driving beginning about 2 hours earlier
each day) and two in Canada (four 13-hour trips of late-night-to-morning driving
beginning at about the same time each evening or of afternoon-to-night driving
beginning 1 hour later each day). RESULTS: Drivers averaged 5.18 hours in bed
per. day and 4.78 hours of electrophysiologically verified sleep per day over
the five-day study (range, 3.83 hours of sleep for those on the steady 13-hour
night schedule to 5.38 hours of sleep for those on the steady 10-hour day
schedule). These values compared with a mean (+/-SD) self-reported ideal amount
of sleep of 7.1+/-1 hours a day. For 35 drivers (44 percent), naps augmented the
sleep obtained by an average of 0.45+/-0.31 hour. No crashes or other vehicle
mishaps occurred. Two drivers had undiagnosed sleep apnea, as detected by
polysomnography. Two other drivers had one episode each of stage 1 sleep while
driving, as detected by electroencephalography. Forty-five drivers (56 percent)
had at least 1 six-minute interval of drowsiness while driving, as judged by
analysis of video recordings of their faces; 1067 of the 1989 six-minute
segments (54 percent) showing drowsy drivers involved just eight drivers.
CONCLUSIONS: Long-haul truck drivers in this study obtained less sleep than
is required for alertness on the job. The greatest vulnerability to sleep or
sleep-like states is in the late night and early morning.
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