High incidence of truck drivers falling asleep at the wheel

A total of one out of three Flemish truck drivers admits to occasionally or regularly dozing off while driving. This alarming finding has emerged from research by the public health department of Ghent University, and received considerable media attention in 2007. The research concluded that one quarter of the truckers surveyed had an increased tendency to fall asleep behind the wheel. Sleeping problems, unhealthy lifestyle and long working hours are the main causes.

Between 2005 and 2007, the Department of Public Health in the Faculty of Medicine and Health Sciences at Ghent University conducted an epidemiological study (in Dutch, 525Kb PDF) on the sleeping and driving habits of Flemish truck drivers.

About the study

Some 474 drivers belonging to 25 transport companies filled in a self-administered questionnaire; the response rate was 31%. The survey included a number of variables on health and driving patterns, as well as three specific modules on sleep habits and disorders:

  • Pittsburgh Sleep Quality Index – surveying overall sleep quality and quantity;
  • Epworth Sleepiness Scale – measuring the propensity to fall asleep;
  • Berlin Questionnaire – probing possible sleep apnea syndrome.

The average age of the drivers surveyed was 42 years. Almost all of the drivers surveyed had a full-time employment contract and 75% of the respondents had more than 10 years of experience as a trucker. Their average monthly professional driving distance was 10,149 kilometres. Overall, one in four drivers conducted their work within Belgium only. The road traffic accident rate averaged 3.66 accidents throughout the entire career of the drivers.

Possible causes

Sleeping problems

More than half of the truckers surveyed suffered from a lack of sleep and slept at least one hour less than necessary. Some 25.5% had a sleep deficit which resulted in an increased probability of falling asleep while driving. Furthermore, one in five truck drivers had an increased risk of developing sleep apnea – a disorder characterised by pauses in breathing during sleep.

Only one quarter of the questioned drivers stated that they started the working week fully rested. Also significant is the fact that one out of three drivers declared that they dozed off occasionally or regularly while driving. A total of 15% of the drivers admitted that this kind of ‘nodding off’ had already resulted in a dangerous traffic situation. For 3.7% of respondents, this dozing behind the wheel had effectively resulted in a traffic accident.

Unhealthy lifestyle

The survey revealed that some 42.3% of the truck drivers were overweight and 26% were obese, one of the recognised causes of sleep problems. Such obesity is a consequence of an unhealthy lifestyle. More than nine out of 10 drivers admitted eating and drinking behind the wheel. Furthermore, 9.2% of the truckers appear to have an alcohol problem, compared with 8% of Flemish men on average. The number of smokers among the truck drivers (46.5%) is also higher than the Flemish average (31.6%).

Work pressure

In general, the drivers work long hours, take too little time off and are often non-compliant with regulations on driving and rest periods. Only a quarter of the respondents take the most effective measures to fight fatigue behind the wheel, that is, stopping the truck to take a nap or to stretch the legs. According to the truck drivers, more autonomy in organising their driving schedule is crucial to prevent fatigue behind the wheel.

Overall, the study concludes that both sleep quality and quantity in the group of truck drivers are low. These poor sleep characteristics are associated with a higher road accident rate. The analysis finds a link between such sleeping problems and the long working hours, difficulties in complying with rest periods, and poor sleep regime within an unhealthy lifestyle. The study concludes that there is considerable room for improvement in sleep education, risk prevention and medical follow-up.

Reactions of social partners

The social partners of the road transport subsector gave different reactions to the media regarding the study, particularly among the employers. The Royal Belgian Federation of Transport and Logistic Service Providers (Fédération Royale Belge des Transporteurs et des Prestataires de Services Logistiques/Koninklijke Federatie van Belgische Transporteurs en Logistieke Dienstverleners, Febetra) questioned the representativeness of the study – comprising only 25 companies – and rejected the research result. Conversely, the Royal Professional Organisation for Flemish Road Hauliers and Logistic Service Providers (Organisation Professionnelle Royale des Entrepreneurs de Transports de Marchandises et des Prestataires de Services Logistiques Flamands/Koninklijke Beroepsorganisatie van de Vlaamse Goederenvervoerders en Logistieke Dienstverleners, SAV) took the findings very seriously and announced that it was setting up a campaign to promote healthier food habits, ways of living and sleep practices among truckers.

The trade unions, for example the socialist Belgian Transport Workers’ Union (Union Belge des Ouvriers du Transport/Belgische TransportarbeidersBond, BTB), used the study as an opportunity to criticise the work pressure and long working hours of truck drivers. Truckers do not have a healthy lifestyle or sufficient relaxation due to long working hours, according to the trade union in a newspaper article on the study. BTB also highlighted the problem of insufficient comfortable and safe parking places where truck drivers could rest.


The study received considerable media attention as the results highlight concerns regarding the safe driving of truck drivers. These concerns are already evident in public opinion, because trucks are often the cause of serious road accidents in Belgium.


Verpraet, R., Epidemiologisch onderzoek naar de slaap- en rijgewoontes bij Vlaamse beroepschauffeurs [Epidemiological study on sleeping and driving habits of Flemish truck drivers], Ghent University, 2007.

De Tijd, 10 April 2007 (newspaper article)

Guy Van Gyes, Higher Institute for Labour Studies (HIVA), Catholic University of Leuven

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