State v. Bell, 429 S.W.3d 524 (Tenn. 2014).

The standardized tests resulted from an evaluation process by the National Highway Traffic Safety Administration (“NHTSA”). David Sandler, Expert and Opinion Testimony of Law Enforcement Officers Regarding Identification of Drug Impaired Drivers, 23 U. Haw. L. Rev. 151, 151 n.2 (2000); Stephanie E. Busloff, Comment, Can Your Eyes Be Used Against You? The Use of the Horizontal Gaze Nystagmus Test in the Courtroom, 84 J. Crim. L. & Criminology 203, 203 (1993) (“Busloff”). In 1984, NHTSA published an instruction manual for training law enforcement officers in the tests determined to be the most effective for evaluating intoxication at roadside: the walk-and-turn, the one-leg stand, and the HGN. Busloff, 84 J. Crim. L. & Criminology at 203, 207. Obviously, the “non-standardized” tests are not included in the battery of tests determined by NHTSA to be the most effective for evaluating intoxication at roadside. See id. at 203 n.1, 207. However, neither party has urged this Court to consider performance on the non-standardized tests differently than that on the standardized tests.
State v. Bell, 429 S.W.3d 524, 527 n.6 (Tenn. 2014)