What are the different sobriety tests?

According to the NHTSA's Appendix A, the best sobriety tests consist of the breathalyzer, horizontal gaze nystagmus (HGN), walk-and-turn (WAT), and the one-leg stand (OLS). The only test that can be safely used alone is the breathalyzer. According to a study conducted in 1998, the HGN accurately identified 88% of individuals with a blood alcohol level of .08, the WAT identified 79% of the individuals, and the OLS had an 83% accuracy rate. Using all three techniques together, provided a combined accuracy rate of 91%. Therefore, if you are sober and you have been pulled over by a police officer, ask for a breathalyzer. You do not want to fall into the 9% that fail the sobriety test when your blood alcohol level is below .08.