Accident reports filled out by police officers are often criticized and described as inaccurate and incomplete sources of data. Yet they contain valuable information and provide the first input of any road safety information system. A recent review of the accident report form, a survey of police practice, crosschecking studies with coroners and insurance claim files, many years of accident report data analysis and comparisons with North American and international trends, have increased our understanding of the value of accident reports as sources of data and as a basis for sound knowledge.

This paper deals with accident underreporting, assessment and use of data coded by police officers and results of data analysis conceming road users. Rates of underreporting, identification of weak areas in the accident report and illustrations of the usefulness of accident data in recent studies are considered.