Fig. 1From: Marijuana use in U.S. teen drivers: a comparison of a road-side survey of reported use and fluid tests for tetrahydrocannabinol (THC)Proportion Testing Positive for THC Within Each Category of Time-Since-Last Used Marijuana and Time-Since-Last-Used Tobacco. Figure Legend 1: The percent positive for THC by time since last used marijuana (shown in solid green) and for time since last used tobacco (shown in blue stripes), National Roadside Survey, 2013–2014Back to article page