Working conditions and risk exposure of employees whose occupations require driving on public roads - Factorial analysis and classification.

INTRODUCTION: Several studies of the working conditions of drivers, and in particular on their pace of work, have enabled a better understanding of the risk factors for road accidents that occur during work. However, few studies are available on the risk exposure and working conditions of employees whose occupations involve driving. The purpose of this paper is to identify the different groups of employees occupationally exposed to road risk and to classify them according to working conditions. METHODOLOGY: A Multiple Correspondence Analysis (MCA) was implemented on the 41,727 individuals from the SUMER 2010 survey (Medical Monitoring of Occupational Risk Exposure: SUrveillance Médicale des Expositions aux Risques professionnels) and for 45 variables about working conditions. The analysis used 5 categories of weekly driving exposure as a supplementary variable (variable which is not used to perform the MCA): Non-exposure; Exposed <2 h; Exposed 2-10 hours; Exposed 10-20 hours; and Exposed >20 h. The results of the MCA were used to construct an ascending hierarchical classification. RESULTS: The first factorial axis differentiates between conventional and unconventional work schedules. Axis 2 differentiates modalities corresponding to the working hours of the most recent working week. The third axis chiefly contrasts persons who have rules to follow with those who have none. An ascending hierarchical classification distinguishes 10 clusters of individuals according to working conditions. Four clusters of employees were excessively exposed to occupational driving. Clusters also have distinct demographic, occupational and psychosocial characteristics. CONCLUSION: Analysis of data from the SUMER survey confirms that employees exposed to road risk are particularly affected by atypical work time characteristics, but can be found in all activity sectors and in all types of job.

Pregnant women in vehicles: Driving habits, position and risk of injury.

This study proposed to broadly examine vehicle use by pregnant women in order to improve realism of accident simulations involving these particular occupants. Three research pathways were developed: the first consisted in a questionnaire survey examining the driving habits of 135 pregnant women, the second obtained measurements of 15 pregnant women driving position in their own vehicle from the 6th to the 9th month of pregnancy by measuring distances between body parts and vehicle parts, and the third examined car accidents involving pregnant occupants. Results obtained indicate that between 90% and 100% of pregnant women wore their seat belts whatever their stage of pregnancy, although nearly one third of subjects considered the seat belt was dangerous for their unborn child. The measurements obtained also showed that the position of the pregnant woman in her vehicle, in relation to the various elements of the passenger compartment, changed significantly during pregnancy. In the studied accidents, no correlation was found between the conditions of the accident and the resulting fetal injury. Results reveal that pregnant women do not modify significantly the seat setting as a function of pregnancy stage. Only the distance between maternal abdomen and steering wheel change significantly, from 16 cm to 12 cm at 6 and 9 month respectively. Pregnant women are mainly drivers before 8 months of pregnancy, passengers after that. Car use frequency falls down rapidly from 6 to 9 months of pregnancy. Real crashes investigations indicate a low rate of casualties, i.e. 342 car accidents involving pregnant women for a period of 9 years in an approximately 1.7 million inhabitants area. No specific injury was found as a function of stage of pregnancy.

Benzodiazepine-like hypnotics and the associated risk of road traffic accidents.

The aim of the study was to investigate the association between the use of benzodiazepine or benzodiazepine-like hypnotics and the risk of road traffic accidents. Data from three French national databases were matched: the health-care insurance database, police reports, and the police database of injury-related traffic accidents. A total of 72,685 drivers involved in injury-related road traffic accidents in France, from 2005 to 2008, were included in the study. The risk of being responsible for a traffic accident was higher in users of benzodiazepine hypnotics (odds ratio (OR) = 1.39 (1.08-1.79)) and in the 155 drivers to whom a dosage of more than one pill of zolpidem a day had been dispensed during the 5 months before the collision (OR = 2.46 (1.70-3.56)). No association was found between the use of zopiclone and risk of traffic accidents. Although this study did not find any association between the use of zolpidem as recommended and causation of traffic accidents, the potential risk related to possible abuse of the drug and risky driving behaviors should be further investigated. The results related to benzodiazepine hypnotics are consistent with those of previous studies.

Limits of the quasi-induced exposure method when compared with the standard case-control design. Application to the estimation of risks associated with driving under the influence of cannabis or alcohol.

The disparities between the quasi-induced exposure (QIE) method and a standard case-control approach with crash responsibility as disease of interest are studied. The 10,748 drivers who had been given compulsory cannabis and alcohol tests subsequent to involvement in a fatal crash in France between 2001 and 2003 were used to compare the two approaches. Odds ratios were assessed using conditional and unconditional logistic regressions. While both approaches found that drivers under the influence of alcohol or cannabis increased the risk of causing a fatal crash, the two approaches are not equivalent. They differ mainly with regards to the driver sample selected. The QIE method results in splitting the overall road safety issue into two sub-studies: a matched case-control study dealing with two-vehicle crashes and a case-control study dealing with single-vehicle crashes but with a specific control group. Using a specific generic term such as "QIE method" should not hide the real underlying epidemiological design. On the contrary, the standard case-control approach studies drivers involved in all type of crashes whatever the distribution of the responsibility in each crash. This method also known as "responsibility analysis" is the most relevant for assessing the overall road safety implications of a driver characteristic.

Are restrained children under 15 years of age in cars as effectively protected as adults?

AIM: To compare the injury distribution between children and adults, injured as restrained car passengers. METHODS: Population based study of data from a French road trauma registry in 1996-2002. Children under 15 years old were compared with adult casualties according to the distribution of serious injuries in three distinct body regions (head, chest, and abdomen) when they were restrained car passengers. A multivariate logistic regression was performed to quantify the risk of AIS2+ injury (Abbreviated Injury Scale of 2 or more). RESULTS: Among the 7568 casualties who were injured as restrained car passengers in car accidents, 1033 were less than 15 years old. Overall, 35.4% of children and 25.2% of adults were unrestrained. For children and adults, the risk of fatality was significantly reduced when they were restrained, but the percentages of children with Injury Severity Score (ISS) > or =16, were not significantly different between restrained and not restrained casualties. Compared to adults, restrained children aged 5-9 were 2.7 times (OR 2.74; 95% CI 1.17 to 6.43) as likely to sustain an AIS2+ abdominal injury, and tended to be more at risk of AIS2+ head injuries, but were less at risk of AIS2+ chest injuries. CONCLUSIONS: Children aged 5-9 years injured in road accidents as restrained car passengers were more likely to sustain an AIS2+ abdominal injury than adults. This emphasises the need to reinforce educational campaigns aimed not only at getting children into restraint systems, but also insisting on their correct use.

[Differences between males and females in traffic accident risk in France]. / Différences entre les hommes et les femmes face au risque routier.

BACKGROUND: In France 7,720 people were killed in traffic accidents in 2001, 75% of which were men; the number of injured people is estimated at 153,945, of which 65% were men. The objective of the study is to describe differences between males and females regarding accidents, and to explain the main reasons for these differences. METHODS: Analysis is conducted from both national police data (2001) and data from the Rhone medical road accident trauma Register (1996-2001). RESULTS: The male/female incidence rate is 3.1 for mortality (95% CI: 3.0-3.3) and 1.7 for morbidity (95% CI: 1.7-1.8). Two-wheel motorised vehicle accidents are very specific to males, which explains part of this overrepresentation. The fatality rate and the severe injuries rate among survivors are higher for males. This is true for every main user group (car users, motorised two-wheelers, cyclists, pedestrians) after adjusting for accident circumstances and age of casualties. Males are more severely injured for all body regions and have more often severe after-effects. CONCLUSIONS: This paper shows the mechanisms leading to this unfavourable outcome for men. They correspond to differences in the number of trips, in the choice of road transport types, and moreover to differences in risk-taking behaviours. Underlying these behaviours, deep-rooted, strong and rather invariant differences between genders are to be found in the values associated with risk-taking on the road.

Experimental investigation and biomechanical analysis of lower limb movements for clutch pedal operation.

Lower limb movements for clutch-pedal operations were investigated and the influence of four parameters (seat height, pedal travel, pedal travel inclination, pedal resistance) was studied using a multi-adjustable experimental seat. Fifteen subjects participated in the experiment: five short females, five average height males and five tall males. A biomechanical model has been proposed to explain how pedal force direction could be controlled. The experimental observations show that the lower limb movement of clutch pedal operation is mainly guided by the geometric constraints imposed by the task and its environment, especially during the depression phase. The results support the hypothesis that movements obey the principle of minimum work and minimum discomfort. Furthermore, it seems that a functional segmentation exists between the distal joint (ankle) and the proximal joints (knee and hip), thus simplifying the control problem, which is due to the redundancy of the human body. It appears that the depression movement is controlled by proprioceptive feedback related to foot displacement and pedal force, from the fact that the deceleration duration during the depression phase increases with the pedal resistance and pedal travel. The minimum pedal resistance and pedal travel are discussed.