The Intoxilyzer breath test machines currently used throughout the country test a sample of deep lung air to measure blood alcohol volume in the breath. The machine can be used with a minimal amount of training and technical skill. It’s not invasive like a blood draw or embarrassing like having to be watched while urinating. Results can be processed quickly, under any circumstance (you are always breathing, but not always needing to urinate), and without any outside technicians.