This paper discusses the implications of Bill C-46 and the new drug-impaired driving law. It examines Canada’s current impaired driving laws, and then reviews the proposed amendments to the Criminal Code in Bill C-46. It discusses prohibited blood-drug concentrations, roadside drug testing, and the challenges associated with testing for marijuana impairment. This paper is part of a collection presented at LESA’s Legalization of Marijuana program in Edmonton on May 17, 2018 and in Calgary on May 24, 2018.