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Article reviewed: Distribution of road accidents in policemen on
shift-work on Italian highways: the contributing role of sleepiness
Sleep Disorders Center, Department of Neurology, San Raffaele Institute, Milan, Italy
Assess the time distribution of road accidents and
the possible role of sleepiness among Italian highway-
patrol policemen working rotating shifts covering the
Cross-sectional study over a 4-year period.
Italian police shift-work operators on the highway
patrols in the period 1993–1997 who reported having
a trafﬁc accident while on duty (mean age ^ SD
35.5 ^ 9.1 years) from a sample of, on average,
about 600 police every day on the Italian highways.
They worked rapidly rotating shifts each lasting 6 h (4
days working and 1 day off) occurring in the following
order: 19:00 to 01:00 h (1st day), 13:00 to 19:00 h
(2nd day), 07:00 to 13:00 h (3rd day) and 01:00 to
07:00 h (4th day), day off (5th day).
All the reported road accidents (n ¼ 1218) were
analyzed each hour for temporal occurrence and
subject characteristics (noted by time of the day, age
of the policeman at the wheel, working period and
years of shift-work). Data, adjusted for trafﬁc density,
were compared with the same data from the general
population in the same period of time and on the same
Sleep–wake habits of policemen involved in the
accidents were determined from detailed telephone
interviews by trained physicians of the State Police.
Possible relationships between trafﬁc density and
temporal distribution of accidents in the 24-h periods
were analyzed using linear regressions. Group and
cluster analyses were used to evaluate particular
patterns of accident distributions in relation to two
regressors (low and high trafﬁc density). The impor-
tance of fatigue (at the wheel) and sleep homeostasis
were also analyzed by linear regression. Spearman
correlation statistics were calculated with dependent
variables of accidents ascribed to sleepiness both in
shift work policemen and also in the general popula-
tion, at the same time of the day and in the same
Accidents occurring during the day shifts were
signiﬁcantly correlated with the trafﬁc density (from
Sleep Medicine 2 (2001) 561–563
1389-9457/01/$ - see front matter q 2001 Elsevier Science B.V. All rights reserved.
Garbarino S, Nobili L, Beelke M, Balestra V, Carrea P, Ferrillo
F. Med Lav 2000;91:486-493.
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E-mail address: email@example.com (M. Zucconi).