The IAM Policy and Research Division has funded a series of projects over the past few years which have looked in detail at the national accident data on specific issues. A unique aspect of these studies was that they combined accident data for several years. The number of accidents included in the combined data was large enough for more complex and multi-dimensional breakdowns of the data to be carried out than are usually possible. Since 2005, the accident records have included additional information on contributory factors which is designed to provide insights into why and how road accidents happen, to assist in investigating measures aimed at preventing accidents. A total of 77 categories of contributory factor are available. These provide information on the factors which the police officer attending the accident considers may have contributed to the cause of the accident. They are intended to identify the key actions and failures which led directly to the impact. This report presents the results from a small project which has carried out some preliminary analysis of the contributory factors data for the five years that are currently available: 2005 to 2009. The main objective of the project is to analyse and report on contributory factors data for accidents and vehicles to identify the main contributory factors involved for: • drivers and riders in different age groups, men and women • accidents on different types of road • accidents at different times • accident severity. The secondary objectives are: • to identify the role of factors associated with driver error in contributing to road accidents, with a view to focusing on ways to improve the quality of driving • to use this initial analysis to gain an understanding of the potential for the data to be used to support further investigations on specific topics in future, complementing the IAM’s earlier projects based on analysis of the national road accident data. This report presents the results of the initial analysis, with a brief commentary. The focus at this stage is on the eight main groups of factors and the ‘top ten’ individual factors associated with different groups of drivers or accident circumstances (where and when accidents happen). Before that, all of the contributory factors are presented, comparing fatal, serious and slight accidents, to illustrate the full range of information available and the proportion of accidents in which each of the 77 factors is reported. Over the five years (2005-2009) covered by this analysis, there were almost 700,000 accidents which were attended by the police and for which contributory factors were recorded. These are the accidents which are analysed in Sections 2, 3 and 4. They represent about three-quarters of all accidents reported to the police and recorded in the accident database during this five year period. Section 5 presents the contributory factors recorded for cars and motorcycles in accidents which were reported to the police during this five year period and shows how these factors vary with the age of drivers and riders, and the gender of car drivers. The results are summarised in Section 6, along with conclusions on the options for further analysis of the contributory factors data. (Author/publisher)
Samenvatting