Report numberRA-2007-110
TitleAccidents with trucks on motorways in a situation of traffic congestion or road works
SubtitlePart 2 – Analysis of the NIS accident database of Flanders of 1991-2002
AuthorsFrank Van Geirt
Jan Vanrie
Published byPolicy Research Centre for Traffic Safety 2002-2006
Number of pages41
Document languageDutch
Work packageOther: Infrastructure and space

Accidents with trucks on motorways in a situation of traffic congestion or road works compose a serious safety hazard for which solutions are presently not available. Following a review of the literature, a number of hypotheses concerning possible causal factors were formulated in the first part of this study. In this part, we analyse the NIS database of traffic accidents to examine whether these hypotheses can be confirmed by empirical data. The focus is therefore on the situation in Flanders.


The dataset used in the current report is based on the NIS database, containing information on accidents between 1991 and 2002. From the latter, 1054 accidents are selected that meet the following requirements: i) it occurred on a motorway, ii) at least one truck was involved, and iii) in condition of congestion or road work. A first analysis of the data confirms the problem: the proportion of this type of accidents, occurring primarily on the major traffic routes, has increased in recent years and the negative impact, in terms of average number of injured and fatalities, outweighs that of other types of accidents. At present, an appropriate comparison with other European accident data is not yet possible due to inconsistencies in data collection and issues of reliability. Harmonizing data collection on a European level is highly desirable. Next, the current dataset is analysed in greater detail, focusing more on respectively environmental factors, the road user and vehicle properties.


Concerning the possible influence of the road environment, the data show that traffic jams and road works do indeed increase the likelihood of a collision for truck drivers. This type of accident also occurs more frequently under normal weather conditions, with a dry road surface and in daylight.


With respect to driver characteristics, we find that the age distribution for this type of collision is slightly skewed towards the higher age groups. Foreign drivers are relatively more vulnerable in situations of traffic congestion than with road works. Based on the available data, fatigue could not be confirmed as an important contributing factor. Use of alcohol is also not frequently observed in these accidents. Concerning the visual capacities of the driver, blinding by the sun seems to be involved relatively more frequently in these situations. The database does not contain any information regarding the factor of distraction. This is also the case for speed. The specific combination of trucks on motorways and traffic jams/road works, however, might be especially dangerous in this respect. The data do confirm that another type of high risk behaviour, driving too close behind the vehicle in front, is in fact an important contributing element.


Finally, the role of vehicle properties is investigated. The analyses of the effect of specific type of trucks reveals the need for more information on the volume of traffic of freight transport. Technical defects are rarely reported, so additional information on these aspects would also be advisable.

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The Policy Research Centre for Traffic Safety carries out policy relevant scientific research under the authority of the Flemish Government. The Centre is the result of a

cooperation between Hasselt University, KU Leuven and VITO, the Flemish Institute for Technological Research.


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