Abstract
The paper is intended to summarise the main conclusions from a recent DETR (Department of the Environment, Transport and the Regions) report of current knowledge on the effects of cannabis on driving and accident risk, based on a review of available literature. The main conclusion is that there is insufficient evidence of the accident risk concerning cannabis, and suggests that future research should be directed towards the development of transport policy to deal with unresolved issues in relation to cannabis and driving. It must be recognised that such issues may not be readily resolved given the current ethical, legal and technical impediments of the research domain.