Addiction. 2009 December: 104(12):2040-2048. This study finds that THC concentrations persist in whole blood multiple days after drug discontinuation in heavy chronic cannabis users.
Drug Recognition Experts
Testimony from a DRE was improper where the DRE did not personally observe the defendant but instead based his opinion on review of records.
2004 National Highway Traffic Safety Administration (NHTSA) publication targeted to prosecutors. The first section details some of the major problems with prosecuting drug impaired driving cases, such as the lack of any clear correlation between blood drug concentrations and impairment for many drugs (p. 8).