L'effect des mesures de sécurité: Ce que nous avons appris et ce que nous ne savons pas encore. (The effect of traffic safety measures: What we have learnt and what we don't know yet).

A summary of discussions, presented in English and French, expresses disappointment in what is learnt from experience in traffic safety. Dark areas of knowledge are shown, and information of the effectiveness of safety measures is considered too scattered and often of poor quality. A lack of critical overview of evaluation studies and results is regretted.