The video reflects changes to drug-driving legislation which came into effect in March of this year, establishing legal limits for the levels of eight 'recreational' drugs and eight legal, prescription medicines. The video was produced with the assistance of The Transport Research Laboratory, whose chief scientist Professor Andrew Parkes set out the complexity of drugs and their potential effect on safe driving: “Different drugs have different effects on different people and the picture for road safety is really complicated. But they all have an effect on driving; none of them makes driving better.”