Safety Performance Indicators
Accidents are final outcomes of a road traffic system. Monitoring the operational conditions of traffic, which means monitoring how road users behave in traffic, can help to explain why road safety risk changes. What do we know about appropriate safety performance indicators? The knowledge about this is communicated in this section on Safety Performance Indicators (SPIs).
It should be kept in mind that SPIs represent more or less ideal measurements of relevant behaviour or characteristics whereas actual practice of data monitoring or data availability does not always live up to this ideal. For two SPIs concerning alcohol and drugs, and speed, the reasons for developing these SPIs are presented and appropriate SPIs are proposed.