This article originally appeared at https://www.sciencedirect.com/science/article/abs/pii/S0376871615003142 Authors: Rebecca L. Hartman ab, Timothy L. Brown c, Gary Milavetz d, Andrew Spurgin d, Russell S. Pierce e, David A. Gorelick af, Gary Gaffney g, Marilyn A. Huestis a https://doi.org/10.1016/j.drugalcdep.2015.06.015Get rights and content Abstract Background Effects of cannabis, the most commonly encountered non-alcohol drug in driving under the influence cases, are heavily debated. We aim to determine how blood Δ9-tetrahydrocannabinol (THC) concentrations relate to driving impairment, with and without alcohol. Methods…