The study looked at factors that contribute to road traffic accidents in Europe. They found that alcohol, speeding, and distractions like using a cell phone are the most important factors. These factors are more likely to cause accidents and are common in traffic. The researchers used accident databases to analyze the causes of accidents and found that unadapted speed and inattention were common factors in accidents. Overall, the main factors that lead to road accidents are alcohol, speeding, and distractions.