Traffic accident reduction by monitoring driver behaviour with in-car data recorders.

People who are aware of being observed tend to modify their behaviour. This phenomenon could potentially be used to encourage individuals to behave more safely when driving if there were means of providing feedback to the drivers about their behaviour on the road. So-called 'vehicle data recorders' offer such a means of providing behavioural feedback by confronting drivers with their recorded driving actions. A field trial of a 'matched experimental/control group design with intervention' was planned with the objective of investigating whether this feedback mechanism would reduce the number of road traffic accidents in everyday driving conditions. In the study, seven experimental vehicle fleets were involved, which varied widely in terms of the kind of transport sector concerned, the type of vehicles used, and the traffic circumstances in which the vehicles are operated. Each fleet was matched with at least one control vehicle fleet, taking into account those relevant traffic safety characteristics. In total, accident and exposure data were collected for 840 vehicles of which 270 equipped with a recorder. During an observation period representing a total of about 3,100 vehicle years, these vehicles were involved in 1,836 road accidents. Analysis of the effects of the use of data recorders in these fleets resulted in an average estimated accident reduction of some 20%. The analysis shows that the actual savings vary depending on the transport sector involved and on the prior level of the fleet's safety record. Further studies are needed to identify the more promising application of such a use of traffic data recorders as a means of reducing road accidents.