“It is really difficult to exaggerate the importance of traffic accidents as a public health problem”. The doctoral thesis “Induced exposure method and its implementation in traffic accidents in Spain”, presented under the supervision of teachers Lardelli Claret and Luna del Castillo by Javier Moreno Rodríguez in the doctorate curriculum “Epidemiology and Public Health”, imparted by the University of Granada. This study is fruit of a research project financed by the Health Research Fund, whose general aim was to assess the impact of the driver’s characteristics on the risk of suffering a traffic accident in Spain, using the induced exposure method suggested by Cuthbert.
This British mathematician formulated in 1994 a model that measures the relative risks of suffering a traffic accident from the data included in the accident registers for the different driver categories by means of comparing the rate of drivers involved in simple accidents and in multiple accidents. Nevertheless, Cuthbert’s model showed some defects in their methodological developments which have been made up for; this way its validity to analyse the driver’s and car’s features has increased and it can also be used to study environmental conditions.
Results
The modified method has been implemented in a series of cases with drivers with a minimum age of 18 involved in the traffic accidents with casualties registered by the State Traffic Office (DGT) during the period from 1990 to 1999. Some of the most relevant are:
Exceeding the speed limit is the factor with a highest impact on the risk of suffering a traffic accident, regardless the driver’s characteristics and the environmental conditions.
The age is strongly connected with the accident rate; the youngest group, that of the drivers aged between 18 and 24 years old is the one with a highest risk, which gradually decreases as the age increases until the decade between 55 and 64 years old, when it starts to increase moderately.
Men run slightly higher risk in all the age periods, but this relationship is not constant in the different environmental and personal circumstances. The risk rate is higher at night and dusk than during the day, and in this case there is not almost any difference by sex. In conditions of driving uninterruptedly for more than an hour the rate changes, cancelling each other in the young and reversing in older drivers.
With regard to alcohol, included in the variable “psychophysical conditions” of the survey with accidents with casualties based on the register of the DGT, its intake significantly increases the risk of accident, although the inadequate quality of this heterogeneous variable makes rigorous assessment of the results difficult.
Driving with someone else in the car involves a significant risk of suffering an accident in all the age and sex sections, although it is higher for young men. In the same way, the risk of being with someone is higher on the road, where it can be more than twice as high with regard to driving alone than in urban areas.
Driving at night and dusk involves a globally moderate risk with regard to driving by day, although it is different according to the age and sex group, as in young men it can be double and it is null in middle-aged women.
the surface of wet or altered road produces an average increase of risk of about 70 %, and this adverse effect is higher for women than for men.
Alcohol
With regard to the information included in the register of accidents with casualties of the Traffic State Office (DGT) there is not a validity problem with the environmental variables or the age and sex of the driver, and in general with most of the data, except those for the variable called “psychophysical conditions”. From 1993, this variable includes the following categories: 1) Seemingly normal. 2) Alcohol without breath test. 3) Alcohol with positive breath test. 4) Drugs. 5) Sudden illness. 6) Drowsiness. 7) Tiredness. 8) Concern.
According to the author of the thesis, Javier Moreno, “from the structure of the classification we can deduce that in Spain, unlike other countries, the implementation of the breath test is not compulsory for all the drivers involved in a traffic accident, which explains poor rate of drinkers which appears in the register of the DGT, in contrast to numerous studies from other countries. “That is why –Moreno goes on—it is so difficult in practice to assess suitably from the accident register of the DGT the risk of the different personal circumstances included in the variable “psychophysical conditions”, which includes, besides alcohol, other high-risk factors extensively checked in bibliography, such as drowsiness or illegal drug consumption. It would be advisable to separate such different factors, the creation of a specific variable for alcohol is unavoidable”.
Reference: Javier Moreno Rodríguez. Dpt. of Preventive Medicine and Public Health. University of Granada.
Phone number: 649786097.
E-mail: franciscoj.moreno.sspa@juntadeandalucia.es
