Fig. 1From: Validity of oral fluid test for Delta-9-tetrahydrocannabinol in drivers using the 2013 National Roadside Survey DataPercentages of Drivers with Positive and Negative Blood THC at Different Levels of Oral Fluid THC Concentration using the Data of Drivers Aged 16 Years and Older with both Blood and Oral Fluid THC Test Results in the 2013 NRS (n = 4596)Back to article page