| PAS Tests | | | | the Alco-Sensor III or IV. The Alco-Sensor utilizes |
| Preliminary Alcohol Screening devices, commonly | | | | fuel cell technology to detect the presence of |
| referred to as PAS tests, are one of the types | | | | alcohol in a breath sample. This handheld device is |
| of field evidence police officers use in determining | | | | relatively small and is powered by a 9-volt |
| probable cause to make an arrest. Although | | | | battery. It has a mouthpiece tube that the DUI |
| officers don't often reveal this, a person stopped | | | | suspect blows into, and a sample chamber where |
| for a DUI is not obligated to take the PAS test, | | | | the air goes. It determines alcohol concentration |
| as it is a voluntary test and is not subject to the | | | | by measuring the electrical reaction caused by |
| "implied consent" laws. | | | | alcohol oxidation. |
| The most widely used PAS device in California is | | | | |