The motorway operating companies supply the laboratory with all data on motorway accidents: 5000 accidents per year involving corporal injury and material damage only, over about 1000 km from Paris to Perpignan. The processing of the accident data leads to a better understanding of the functioning of safety fences and the aggressive nature of unequipped shoulders. This data is coded and structured for use with the INGRES data base management system and the associated 4th generation language on a VICTOR personal computer connected to a local area network.
The structure of the data in this relational data base brings out the basic features of an accident: general information on the accident, description of the impact and vehicle trajectory or trajectories, information on the road safety equipment involved and on the victims of the accident. The system can be used as (a) a computer-aided input facility (b) for the systematic analysis of accidents and (c) in service evaluation of the safety fences. The data base management system, which is easy to use, allows the user to write out his own specific queries with constant access to the data base. A relation between the accidents and the characteristics of the road is to be established on interconnecting our "accident oriented" data base with a "road safety equipment orientated" one that is now being developed.